Geosciences doi: 10.3390/geosciences14030084
Authors: Mélani Berrocal-Casero Ricardo Pimentel Pedro Miguel Callapez Fernando Barroso-Barcenilla Senay Ozkaya de Juanas
Carentonosaurus soaresi was recently described in the uppermost middle Cenomanian (Upper Cretaceous) of Casais dos Carecos (Coimbra, western Portugal) based on a diverse set of new material (cervical and dorsal vertebrae) of the Pythonomorpha lizard. The main morphological characteristics observed in the vertebrae used for the diagnosis of this species are the presence of distinct lateral and subcentral foramina, highly laterally projected paradiapophyses beyond the prezygapophyses, a low subrectangular neural spine ornamented with longitudinal grooves, and dorsal vertebrae displaying a sagittal furrow along the ventral surface. Additional diagnostic details observed both in new material and the previously studied vertebrae are described herein, such as the presence of keels in the zygantrum and zygosphene. These and other important morphological characteristics present in the species soaresi are absent in the genotype Carentonosaurus mineaui and in other known Squamata, allowing for the definition of the new genus Segurasaurus.
]]>Geosciences doi: 10.3390/geosciences14030083
Authors: Samir Samaoui Ayoub Aabi Abdellah Boushaba Belkasmi Mohammed Abdellah Nait Bba Abderrahim Essaifi Lahssen Baidder Othmane Lamrani
The Ougnat Massif of the eastern Anti-Atlas (Morocco) hosts barite and sulfide vein-type deposits of vital economic importance. With over 150 mineralized structures reported in the Ougnat Massif, the ore-bearing ones are predominantly composed of barite, quartz, calcite, and minor portions of sulfides. The mineralized veins are driven by NW-SE and NE-SW to E-W oblique-slip opening faults that cross both the Precambrian basement and its Paleozoic cover. The mineralized structures occur as lenses and sigmoidal veins that follow stepped tension fracture sets oblique to the fault planes. These geometries and kinematic indicators of these structures point to a predominantly normal-sinistral opening in a brittle-ductile tectonic setting. The S isotopic compositions of barite from the Ougnat Massif (+10.8 to +19.5‰) fall mostly within the range of δ34S values of Late Triassic to Jurassic seawater, thus suggesting that some of the SO2− in barite comes from seawater sulfate. This range of δ34S values also corresponds approximately to the hydrothermal barite context. The 87Sr/86Sr ratios of barite, which range from 0.710772 to 0.710816, lie between the radiogenic strontium isotopic compositions of deposition by hydrothermal solutions, and also coincide with the non-radiogenic isotopic signature of Triassic to Jurassic seawater. Based on a fluid inclusions study, the ore-forming fluids were a mixture of two or more fluids. A deep hot fluid with an average temperature of 368 °C leached the granodiorites and volcanic-sedimentary complex of the Ouarzazate Group. This fluid provided the hydrothermal system with most of the Ba, radiogenic Sr, and some of the dissolved S. A second, shallow fluid with an average temperature of 242 °C was derived from Late Triassic to Jurassic seawater. The barite mineralization of the Ougnat Massif constitutes a typical example of vein-type mineralization that occurred along the northern margin of the West African Craton and regionally tied to the central Atlantic opening.
]]>Geosciences doi: 10.3390/geosciences14030082
Authors: Fred Prata Stefano Corradini Riccardo Biondi Lorenzo Guerrieri Luca Merucci Andrew Prata Dario Stelitano
Ground-based infrared cameras can be used effectively and safely to provide quantitative information about small to moderate-sized volcanic eruptions. This study describes an infrared camera that has been used to measure emissions from the Mt. Etna and Stromboli (Sicily, Italy) volcanoes. The camera provides calibrated brightness temperature images in a broadband (8–14 µm) channel that is used to determine height, plume ascent rate and volcanic cloud/plume temperature and emissivity at temporal sampling rates of up to 1 Hz. The camera can be operated in the field using a portable battery and includes a microprocessor, data storage and WiFi. The processing and analyses of the data are described with examples from the field experiments. The updraft speeds of the small eruptions at Stromboli are found to decay with a timescale of ∼10 min and the volcanic plumes reach thermal equilibrium within ∼2 min. A strong eruption of Mt. Etna on 1 April 2021 was found to reach ∼9 km, with ascent speeds of 10–20 ms−1. The plume, mostly composed of the gases CO2, water vapour and SO2, became bent over by the prevailing winds at high levels, demonstrating the need for multiple cameras to accurately infer plume heights.
]]>Geosciences doi: 10.3390/geosciences14030081
Authors: Salomé C. Custódio Maria Helena Henriques Emmaline M. Rosado-González Nuno M. Vaz Artur A. Sá
The “Atlantic Geopark” Project corresponds to the first stage of a broad project addressing a future application to the Global Geopark Network of a territory located in Portugal: “The Atlantic Geopark: 600 million of geological history”. It covers six central littoral and rural municipalities (Cantanhede, Figueira da Foz, Mealhada, Mira, Montemor-o-Velho, and Penacova), which display special and singular geodiversity, and it includes geological heritage with international relevance representing the opening and closing of the Rheic Ocean, the formation and breakup of Pangea, and the opening of the North Atlantic Ocean. Besides the geological heritage, here presented through the description and characterization of six geological sites (one per municipality) which served as anchors for the development of the project currently underway, the territory also provides other geoheritage resources related to uses of the local geological features. These resources hold significance in bolstering an application to the Global Geopark Network soon. They encompass partially artificial elements such as road excavations, agricultural soils, and quarries, as well as entirely artificial elements such as interpretation centers and museums. These elements serve as tangible representations of the various ways in which the Earth and local communities interact.
]]>Geosciences doi: 10.3390/geosciences14030080
Authors: Fredy Alberto Huamán-Mamani Cris Katherin Palomino-Ñaupa María del Mar Orta Cuevas Santiago Medina-Carrasco
Ignimbrite rock is a volcanic material located in the Arequipa region (Peru), and for centuries, it has been used as a construction material, giving a characteristic light pastel, white to pink color to the city of Arequipa, with white being the most common. In the present study, the potential use of three types of Arequipa raw materials (ignimbrite rock powder, calcined clay powder, and demolition mortar powder) as the main source of new binders or the manufacture of environmentally friendly mortars, without the addition of ordinary Portland cement (OPC) is discussed. In this work, an in-depth characterization of the materials used was carried out. The proposed fabrication route for geopolymeric materials was considered for the manufacture of binders and mortars using an alkaline solution of NaOH with values between 12 and 18 molar, as a trigger for the geopolymerization process. Geopolymeric mortars were obtained by adding a controlled amount of fine sand to the previously prepared mixture of binder raw material and an alkaline solution. Conventional OPC and geopolymeric mortars manufactured under the same conditions were mechanically evaluated by uniaxial compression tests at a constant compression rate of 0.05 mm/min and under normal conditions of temperature and atmosphere, where the most optimal values were obtained for 15 molar alkaline solutions of ignimbrite without the addition of aggregates, with values of compressive strength of 42 MPa and a modulus elastic of 30 GPa. The results revealed a significant increase in the maximum strength and modulus of elasticity values when the volumetric fractions of OPC are completely replaced with geopolymeric binders in the study conditions of this work, demonstrating the enormous potential of the ignimbrite rock and construction waste studied, as raw material of alternative mortar binders without the addition of OPC. With this work, the ignimbrite rock, of great value in the region and also found in other areas of the Earth’s geography, was characterized and valued, in addition to the calcined clay and demolition mortar of the region.
]]>Geosciences doi: 10.3390/geosciences14030079
Authors: Evandro Balbi Fabrizio Marini
Linear geo-textures are widely recognized on synthetic scaled images of planetary surfaces and consist of elongated alignments of tonal contrasts. When these linear patterns are clustered in azimuthal sets and organized in domains occurring on specific terranes, they reflect the structural grain of the crust and provide clues on the stress trajectories. In this way, the geostatistical analysis of lineament domains represents a useful tool to highlight the geotectonic settings of planetary surfaces. In this work, we applied a lineament domain analysis to better frame the tectonic evolution of the Claritas Fossae (CF) area on Mars, the origin of which is still debated, and both dip–slip and strike–slip tectonics have been described in the literature. A twofold approach was followed that included the identification of a linear pattern with manual and automatic approaches. The automatic method confirmed and validated the results of the manual detection. The statistical analysis of the identified lineaments showed their clustering in two domains that persisted on different terranes separated by the regionally sized scarp associated with the CF. This scarp is the surface manifestation of the CF crustal fault. The spatial distribution of the two domains and their constant angular relationship of about 30° allowed relating one domain to the main CF fault and the other domain to the extensional deformation associated with the fault kinematics. Our results suggest that the CF frames well within a regional setting characterized by right–lateral kinematics with about 20% transtension. Temporal constraints derive from the ages of the terrains where the two domains develop. On this basis, we propose that a first tectonic event occurred in the Noachian age followed by a reactivation occurring after the emplacement of the Late Hesperian lavas.
]]>Geosciences doi: 10.3390/geosciences14030078
Authors: Wellynne Carla de Sousa Barbosa Antonio José Teixeira Guerra Gustavo Souza Valladares
Soils have an important task in maintaining vegetation cover and natural resources on Earth and are indispensable to societies. However, the accelerated soil erosion has become an environmental problem related to land settlement for agricultural practices and forestry and is linked to population growth. This study aimed to evaluate soil erosion in a watershed downstream of Parnaíba river, northwest of Piauí state, in the Brazilian Cerrado using geotechnology products and tools in order to understand the soil loss and map the potential erosion and actual erosion through qualitative and quantitative results to support the management and planning of the watershed in an effective and efficient way. As a modeling tool, this research used the Revised Universal Soil Loss Equation (RUSLE). The potential erosion ranged from very low to very high. The soil loss obtained by the integration of natural physical factors with land use (anthropic action) resulted in soil loss corresponding to the category slight (0–0.01 t.ha−1.year−1) to extremely high (>100 t.ha−1.year−1). The areas with the greatest soil loss were identified in land uses linked to pasture, exposed soil, and cultivated land. It was also possible to identify erosion features in the field, indicating the need to implement soil conservation practices.
]]>Geosciences doi: 10.3390/geosciences14030077
Authors: Petr Semenov Anfisa Pismeniuk Anna Kil Elizaveta Shatrova Natalia Belova Petr Gromov Sergei Malyshev Wei He Anastasiia Lodochnikova Ilya Tarasevich Irina Streletskaya Marina Leibman
Climate-induced changes contribute to the thawing of ice-rich permafrost in the Arctic, which leads to the release of large amounts of organic carbon into the atmosphere in the form of greenhouse gases, mainly carbon dioxide and methane. Ground ice constitutes a considerable volume of the cryogenically sequestered labile dissolved organic carbon (DOC) subjected to fast mineralization upon thawing. In this work, we collected a unique geochemical database of the ground and glacier ice comprising the samples from various geographic locations in the Russian Arctic characterized by a variety of key parameters, including ion composition, carbon-bearing gases (methane and carbon dioxide), bulk biogeochemical indicators, and fluorescent dissolved organic matter (DOM) fractions. Our results show that interaction with solid material—such as sediments, detritus, and vegetation—is likely the overriding process in enrichment of the ground ice in all the dissolved compounds. Terrigenous humic-like dissolved organic matter was predominant in all the analyzed ice samples except for glacier ice from Bolshevik Island (the Severnaya Zemlya archipelago) and pure (with low sediment content) tabular ground ice from western Yamal. The labile protein-like DOM showed no correlation to humic components and was probably linked to microbial abundance in the ground ice. The sum of the fluorophores deconvoluted by PARAFAC strongly correlates to DOC, which proves the potential of using this approach for differentiation of bulk DOC into fractions with various origins and biogeochemical behaviors. The pure tabular ground ice samples exhibit the highest rate of fresh easily degradable DOM in the bulk DOC, which may be responsible for the amplification of permafrost organic matter decomposition upon thawing.
]]>Geosciences doi: 10.3390/geosciences14030076
Authors: Olivia Nesci Rosetta Borchia Laura Valentini
The ancient Duchy of Urbino (Marche and Emilia-Romagna Regions, Italy) is known for its spectacular landscapes linked to a unique geological history. This area owns an unexpected cultural resource, which concerns using its landscapes in art. Some great Renaissance artists, including Piero della Francesca, Raphael, and Leonardo, were so impressed by the landscapes that they reproduced them in their most famous paintings. This paper summarizes research concerned with their identification, employing a multidisciplinary method that has enabled the recognition of many morphologies. This contribution provides the scientific community with information on the methodology and regional and national projects developed in this area to enhance its cultural landscapes. Starting from the geological description of the territory, the research focuses on famous works by three great Renaissance artists, providing evidence and morphological details related to the recognition of places: “Nativity” by Piero della Francesca, “Madonna Litta” by Leonardo da Vinci, and “Knight’s Dream” by Raphael. Finally, it is proposed to make these landscapes a timeless resource through their inclusion in UNESCO’s cultural heritage. This contribution is addressed to representatives of the administration, conservation, and enhancement of artistic and landscape heritage to stimulate new perspectives for research, education, and tourism within the cultural heritage of this area.
]]>Geosciences doi: 10.3390/geosciences14030075
Authors: Valentina Nikolova Veselina Gospodinova Asparuh Kamburov
Accurate data mapping and visualization are of crucial importance for the detection and monitoring of slope morphodynamics, including erosion processes and studying small erosional landforms (rills and gullies). The purpose of the current research is to examine how the flight geometry of unmanned aerial systems (UASs) could affect the accuracy of photogrammetric processing products, concerning small erosion landforms that are a result of slope wash and temporary small streams formed by rain. In October 2021, three UAS flights with a different geometry were carried out in a hilly to a low-mountain area with an average altitude of about 650 m where erosion processes are observed. UAS imagery processing was carried out using structure-from-motion (SfM) photogrammetry. High-resolution products such as photogrammetric-based point clouds, digital surface models (DSMs) and orthophotos were generated. The obtained data were compared and evaluated by the root mean square error (RMSE), length measurement, cloud-to-cloud comparison, and 3D spatial GIS analysis of DSMs. The results show small differences between the considered photogrammetric products generated by nadir-viewing and oblique-viewing (45°—single strip and 60°—cross strips) geometry. The complex analysis of the obtained photogrammetric products gives an advantage to the 60°—cross strips imagery, in studying erosional terrains with slow slope morphodynamics.
]]>Geosciences doi: 10.3390/geosciences14030074
Authors: Xuewei Zhang Chong Xu Lei Li Liye Feng Wentao Yang
The Taihang Mountains are a critical mountain range and geographical boundary in eastern China. Landslide disasters are particularly common in this region and usually cause serious casualties and property damage. However, previous landslide inventories in the region are limited and lack comprehensive landslide cataloguing. To address this gap, the northern half of the Taihang Mountain Range was selected for this study. A landslide database for the area was constructed using multi-temporal high-resolution optical imagery from the Google Earth and human–computer interactive visual interpretation technology. The results indicate that at least 8349 landslides have occurred in the Taihang Mountain Range, with a total landslide area of about 151.61 km2. The size of the landslides varies, averaging about 18,159.23 m2, with the largest landslide covering 2.83 km2 and the smallest landslide only 5.95 m2. The significance of this study lies in its ability to enhance our understanding of the distribution of landslides in the northern half of the Taihang Mountains. Furthermore, it offers valuable data references and supports for landslide assessment, early warning systems, disaster management, and ecological protection efforts.
]]>Geosciences doi: 10.3390/geosciences14030073
Authors: Soujan Ghosh Sudipta Sasmal Sovan K. Maity Stelios M. Potirakis Masashi Hayakawa
This study examines the response of the thermal channel within the Lithosphere–Atmosphere–Ionosphere Coupling (LAIC) mechanism during the notable earthquake in Crete, Greece, on 27 September 2021. We analyze spatio-temporal profiles of Surface Latent Heat Flux (SLHF), Outgoing Longwave Radiation (OLR), and Atmospheric Chemical Potential (ACP) using reanalysis data from the National Oceanic and Atmospheric Administration (NOAA) satellite. Anomalies in these parameters are computed by removing the background profile for a non-seismic condition. Our findings reveal a substantial anomalous increase in these parameters near the earthquake’s epicenter 3 to 7 days before the main shock. The implications of these observations contribute to a deeper understanding of the LAIC mechanism’s thermal channel in seismic events.
]]>Geosciences doi: 10.3390/geosciences14030072
Authors: Lev V. Eppelbaum
Global warming firstly influences the permafrost regions where numerous and rich world hydrocarbon deposits are located. Permafrost thawing has caused severe problems in exploring known hydrocarbon deposits and searching for new targets. This process is also dangerous for any industrial and living regions in cold regions. Knowledge of permafrost’s ice and unfrozen water content is critical for predicting permafrost behavior during the water–ice transition. This is especially relevant when ice and permafrost are melting in many regions under the influence of global warming. It is well known that only part of the formation’s pore water turns into ice at 0 °C. After further lowering the temperature, the water phase transition continues, but at gradually decreasing rates. Thus, the porous space is filled with ice and unfrozen water. Laboratory data show that frozen formations’ mechanical, thermal, and rheological properties strongly depend on the moisture content. Hence, porosity and temperature are essential parameters of permafrost. In this paper, it is shown that by combining research in three fields, (1) geophysical exploration, (2) numerical modeling, and (3) temperature logging, it is possible to estimate the porosity of permafrost in situ. Five examples of numerical modeling (where all input parameters are specified) are given to demonstrate the procedure. This investigation is the first attempt to quantitatively analyze permafrost’s porosity in situ.
]]>Geosciences doi: 10.3390/geosciences14030071
Authors: John D’Angelo Zeyu Zhao Yifan Zhang Pradeepkumar Ashok Dongmei Chen Eric van Oort
Existing methods for estimating formation boundaries from well-log data only analyze the formation along the wellbore, failing to capture changes in the 3D formation structure around it. This paper presents a method for real-time 3D formation boundary interpretation using readily available well logs and seismic image data. In the proposed workflow, the mean formation boundary is estimated as a curve following the well path. 3D surfaces are then fitted through this boundary curve, aligning with the slopes and features in the seismic image data. The proposed method is tested on both synthetic and field datasets and illustrates the capabilities of accurate boundary estimation near the well path and precise representation of boundary shape changes further away from the well trajectory. With this fully automated geological interpretation workflow, human bias and interpretation uncertainty can be minimized. Subsurface conditions can be continually updated while drilling to optimize drilling decisions and further automate the geosteering process.
]]>Geosciences doi: 10.3390/geosciences14030070
Authors: Vladimir I. Kaftan Alexei D. Gvishiani Alexander I. Manevich Boris A. Dzeboev Viktor N. Tatarinov Boris V. Dzeranov Alina M. Avdonina Iliya V. Losev
This paper analyzes and reviews the rapid uplifts of the Earth’s crust in the Caucasus that occurred over the last century. The uplifts were registered by precise repeated state leveling and reflected on officially published maps of vertical movements of the Earth’s crust. This study summarizes information on the region’s vertical movements over more than a century. The present study describes the technology for creating maps of recent vertical movements of the Earth’s crust using precision leveling data. This paper summarizes cases of recording uplifts of the Earth’s surface in other regions of the world in connection with seismic activity. The authors carried out intercomparison of vertical movements with tectonics, seismicity, and geophysical fields, which discovered their apparent mutual correspondence. This indicates the deep tectonic nature of the observed uplifts of the Earth’s crust. Spatial and temporal agreement with the distribution of strong earthquakes showed a natural relationship. It has been shown that strong earthquakes are confined to the boundaries of zones of rapid uplift. They occur predominantly in areas of transition between uplifts and subsidence. The results obtained demonstrate the role of the study and observations of vertical movements of the Caucasus in assessing periods and areas of increased seismic hazard.
]]>Geosciences doi: 10.3390/geosciences14030069
Authors: Dimitra Boundi Dimitrios Papanikolaou Giulia Bosio Chiara Montemagni
Late Cretaceous metamorphic events are known in Crete and the Cyclades from klippen above the External Hellenides. This work extends their occurrence to the North Aegean area within the tectonic units of the Internal Hellenides. New 40Ar/39Ar white mica ages from garnet-bearing micaschists of the Upper Metamorphic Unit of Skyros Island, cropping out in the Skyrian Olympus Mountain, document a Late Cretaceous tectono-metamorphic evolution. Several mica generations have been distinguished using electron probe microanalyses and were dated using the 40Ar/39Ar method: a relict mica older than 96 Ma, followed by a foliation-forming mica of about 88–84 Ma and alteration phases ≤ 68 Ma were recognized. This Cretaceous tectono-metamorphic evolution falls between the closure of the internal Axios/Vardar oceanic basin in the Late Jurassic–Early Cretaceous, and the closure of the external Pindos–Cyclades oceanic basin in the Early Cenozoic. The position of the Upper Metamorphic Unit of Skyros was probably within the evolving Hellenic volcanic/magmatic arc during the continuous subduction of the African plate beneath the European plate. The present tectonic position of the units bearing the Late Cretaceous metamorphic event is the result of the Cenozoic tectonic emplacement onto the more external units across the Hellenides from the Pelagonian to the Pindos–Cyclades domain.
]]>Geosciences doi: 10.3390/geosciences14030068
Authors: Zhonghai Wu Mengmeng Hu
Active faults are generally defined as faults that have moved in the past and will continue to be active in the future. They are expected to cause deformation and potential disasters if they are localized close to human activities. The definition and classification of active faults are important bases for evaluating the risk. This paper summarizes and compares the history, status, and progress of their definition and classification schemes used in representative countries and regions, as well as in some relevant standards, in active fault mapping, in the construction of spatial databases, and in some other aspects. It is concluded that the current geodynamic setting, existing technical means, geological operability, application purpose, and social acceptability of active faulting hazard in a specific area comprehensively determine the selection of the definition and classification. The key parameter in defining active faults is the time limit. It usually involves four time scales, i.e., Neotectonic (post-Neogene), Quaternary, Late Quaternary, and Holocene. The definition using a short time scale, such as Late Quaternary and Holocene, is usually suitable for the plate boundary zone, which has a high strain rate, but active faults in the intraplate deformation region and stable continental region should be defined with a long time scale, such as the Quaternary and Neotectonics. In addition, the magnitude standard can determine the activity intensity of active faults, which most generally includes three classes, namely, M ≥ 5.0 damaging earthquakes, M ≥ 6.0 strong earthquakes, and M ≥ 6.5 earthquakes that may produce surface displacement or deformation. The M ≥ 5.0 earthquake is generally applicable to regional earthquake prevention and risk mitigation in many countries or regions, but the M ≥ 6.5 earthquake magnitude benchmark is generally used as the standard in rules or regulations regarding active fault avoidance. The most common classification schemes in many countries or regions are based on fault activity, which is reflected mainly by the fault slip rate and fault recurrence interval (FRI), as well as by the last activation time. However, when determining the specific quantitative parameters of the different activity levels of faults, it is necessary to comprehensively consider the differences in activity and ages of the faults in the study region, as well as the amount and validity of existing data for the purpose of classifying different active levels of faults effectively.
]]>Geosciences doi: 10.3390/geosciences14030067
Authors: Beverly Yang Lindsey J. Heagy Josephine Morgenroth Davide Elmo
Technological advancements have made rock engineering more data-driven, leading to increased use of machine learning (ML). While the use of ML in rock engineering has the potential to transform the industry, several methodological issues should first be addressed: (i) rock engineering’s use of biased (poor quality) data, resulting in biased ML models and (ii) limited rock mass classification and characterization data. If these issues are not addressed, rock engineering risks using unreliable ML models that can have potential real-life adverse impacts. This paper aims to provide an overview of these methodological issues and demonstrate their impact on the reliability of ML models using surrogate models. To take full advantage of the benefits of ML, rock engineers should make sure that their ML models are reliable by ensuring that there are sufficient unbiased data to develop reliable ML models. In the context of this paper, the term sufficient retains a relative meaning since the amount of data that is sufficient to develop reliable a ML models depends on the problem under consideration and the application of the ML model (e.g., pre-feasibility, feasibility, design stage).
]]>Geosciences doi: 10.3390/geosciences14030066
Authors: Barry J. Hibbs Christopher J. Eastoe Mercedes Merino
In arid regions characterized by large variations in groundwater salinity, the data derived from irrigation and domestic water supply wells may exhibit bias, reflecting an overall lower salinity than the true aquifer distribution. This bias stems from the decommissioning, non-use, or disrepair of wells that are frequently sources of higher salinity readings, rendering them unavailable for sampling. Baseflow-fed streams, agricultural drains, seeps, springs issuing into agricultural drains, and randomly located test hole samples tend to manifest higher averages and ranges of salinity when compared to supply wells. Agricultural drain flows, springs, and test holes, if sampled following recommended guidelines, are less susceptible to such bias. This study presents a case of groundwater bias identified through an initial water well sampling program in El Paso (Texas, USA). Subsequent rounds of sampling, incorporating drain samples, spring samples, and test hole samples, revealed a more comprehensive understanding of the salinity dynamics. The dataset not only highlights the existence of bias but also provides evidence for a combined geological and agricultural origin of salinity. Additionally, it demonstrates that drain sampling in an earlier study did not accurately depict a primary salinity source due to incomplete analysis of the data. Recommendations are outlined to mitigate bias, emphasizing the importance of sample control from baseflow-fed drains, springs, water wells, and test hole samples. The study also infers the upwelling of saline groundwater from deeper formations in the study area, contributing to a more comprehensive understanding of groundwater salinity dynamics.
]]>Geosciences doi: 10.3390/geosciences14030065
Authors: Giovanna Lucia Piangiamore Alessandra Maramai
The past offers important lessons with regard to facing the future with greater awareness. In this context, school plays a key role in spreading knowledge of natural phenomena and in promoting behavior change. Together with researchers, teachers can be strong allies to build more resilient future citizens. The Istituto Nazionale di Geofisica e Vulcanologia (INGV) school training activities provide tools to prepare for the next earthquake and/or tsunami. Approximately 5000 students, from both middle schools (ISCED 2) and high schools (ISCED 3), were involved in active learning activities based on a flipped-up approach during specific online scientific events during the pandemic. Online lab activities were conducted during European Researchers’ Night (“Earthquakes: history teaches us the future: researchers for a day with experimentation in didactics for ESL”) and during both World Water Day 2021 and World Earth Day 2021 (“Tsunamis: history teaches us the future researchers for a day with experimentation in didactics for ESL”). These two Episodes of Situated Learning (ESL) experiences triggered students’ interest, favoring remote learning, developing life skills, and focusing on historical seismic studies of both past earthquakes and tsunamis.
]]>Geosciences doi: 10.3390/geosciences14030064
Authors: Kristijan Grabar Jasmin Jug Anja Bek Stjepan Strelec
The increasing occurrence of landslides worldwide causes many human casualties and huge socio-economic losses. Therefore, the fastest and most accurate characterisation of landslides is important. The objective of this study is to compare how well the flat dilatometer (DMT) test and the piezocone penetration (CPTU) test can find the depth of a sliding zone. Inclinometers were used to measure horizontal changes in the soil to ensure the depth of the sliding zone was correct. The coincidence of the results of in situ static probes, and the displacements of the inclinometers is a sure confirmation of the depth of the sliding zone. In the example of Bedekovčina and Kravarsko landslides, in situ static probes were used to obtain values of input parameters on the sliding zone for parametric sensitivity analysis of parameters. Sensitivity analysis was performed by plotting the relationship between the above parameters and the vertical effective stress σ′vo on the sliding zone. The sensitivity analysis of the parameters of 11 tested samples shows that for the parameters of the obtained DMT probe, a higher sensitivity of the parameters is obtained, closer to the values concerning the expected range, and a minor standard deviation. The parameter Kd obtained by dilatometer probing is the best indicator of the depth of the sliding zone. The literature value Kd = 1.8–2.0 on the sliding zone in this paper is extended to the range Kd = 1.8–2.5, and its detection sensitivity is influenced by over-consolidation in shallow soil layers. In general, the research results show that the dilatometer probe has an advantage over the piezocone penetrometer test for the needs of landslide characterisation.
]]>Geosciences doi: 10.3390/geosciences14030063
Authors: Mohan Pan Ting Yang Ba Manh Le Yuhang Dai Han Xiao
Magmatism on continental lithospheres induced by mantle plumes is more complex compared to oceanic intraplate volcanism owing to the heterogeneous nature of continental crustal and lithospheric structures. Substantial evidence points to the deep-oriented Hainan mantle plume beneath the Lei–Qiong region, the southernmost of the South China block. In this study, we present a detailed shear wave velocity model of the crust and uppermost mantle in the Lei–Qiong volcanic region, derived from 3-year seismic data (2016–2018) from 34 stations and the use of the ambient noise tomography method. An evident columnar low-velocity anomaly was imaged in the crust and uppermost mantle beneath the Wushi Sag (WSS), Beibu Gulf, potentially suggesting that the center of either one branch or the entirety of the Hainan mantle plume impacts the crust here. This low-velocity anomaly is overlaid by a local Moho deepening, indicative of underplating beneath the existing crust. The Maanling–Leihuling Volcanic Field (MLVF) in northern Hainan Island, previously considered the center of the hotspot, does not exhibit such distinct velocity anomalies. Instead, subtle lower crustal anomalies beneath the MLVF are linked with the upper mantle low-velocity zone beneath the WSS. Additionally, the high-conductivity bodies beneath the MLVF indicate lateral magma transport. Earthquake swarms and deep-seated seismic events beneath the WSS further support the presence of magmatic processes. This study indicates that in the Lei–Qiong region, the interaction of the continental crust with the mantle plume centered in the WSS results in magma exhibiting both vertical ascent and lateral migration, leading to a dual low-velocity shear wave pattern in the upper crust, which significantly influences the surface volcanic activity.
]]>Geosciences doi: 10.3390/geosciences14030062
Authors: Bojana Aleksova Tin Lukić Ivica Milevski Dušan Puhar Slobodan B. Marković
This comprehensive study investigates the intricate interplay between geodiversity, geohazards, and anthropogenic influences within the Kratovska Reka catchment—an area distinguished by its remarkable geosites. Kratovska Reka, spanning a length of 17.3 km, serves as the left tributary to Kriva Reka. The watershed of Kratovska Reka, covering an area of 68.5 km2, is situated on the northwestern inclines of the Osogovo Mts in North Macedonia. Despite harboring exceptional geodiversity, the area lacks protective measures for its myriad geosites. Evaluating susceptibility to geohazards, including excessive erosion, landslides, and flash floods, this research identifies heightened risk zones, particularly in the valley of Kratovska Reka and its tributaries. A multi-hazard model reveals that 56.07% of the basin is vulnerable to geohazards. The study correlates lithological composition, relief features, and morphometric characteristics with geohazards, emphasizing the significance of paleovolcanic relief in resisting excessive erosion. Human-induced factors, notably deforestation and inappropriate land use, amplify geohazards. This research underscores the urgent need for geosite protection and sustainable land management to mitigate geohazards’ impacts. Additionally, it explores the correlation between land use practices and geodiversity, emphasizing the importance of responsible land management in safeguarding the geological and geomorphological values of the researched area.
]]>Geosciences doi: 10.3390/geosciences14030061
Authors: Jeffrey S. Perez Deo Carlo E. Llamas Daniel Jose L. Buhay Ryan Christian C. Constantino Crystel Jade M. Legaspi Kristine Dionne B. Lagunsad Rhommel N. Grutas Marc Marion Y. Quimson
On 15 January 2023, a shallow, moderate earthquake with a magnitude (Mw) of 4.7 and a depth of one kilometer struck the northern part of Leyte Island in the central Philippines. Originating along the northern Leyte segment of the Philippine Fault, a well-established creeping fault, the earthquake caused significant geologic, structural, and socio-economic impacts despite its low magnitude. Probable surface rupture and landslides were reported, leading to a comprehensive field investigation. Our investigation revealed an ~8 km discontinuous surface rupture along the northern Leyte segment of the Philippine Fault, with a maximum left-lateral displacement of 2 cm. This was the first documented occurrence of such a phenomenon associated with an earthquake of a magnitude less than 6, particularly along a creeping fault segment. The maximum ground shaking felt was reported on the PHIVOLCS Earthquake Intensity Scale (PEIS) to be VI (very strong), equivalent to a Modified Mercalli Intensity (MMI) of VI along the fault strike. However, strong motion accelerographs recorded a peak ground acceleration (PGA) of 0.407 g, equivalent to PEIS VIII (very destructive), attributed to local site amplification influenced by subsurface geology. In the area where the local site amplification occurred, limited liquefaction was observed on marshlands with recent and alluvial deposits. Two landslides were observed in the mountainous area west of the fault. Structural damages were noted in areas with PEIS VI intensity and areas transected by the surface rupture. Despite the earthquake’s low magnitude, the event documented significant impacts, including surface ruptures, liquefaction, landslides, and severe structural damage. The peculiarities of this event are attributed to the shallowness of the earthquake source, and local site conditions, including geology, geomorphology, and soil properties, contributed to the severity of the impacts. Moderate in size, this earthquake emphasizes the importance of documenting moderate-sized earthquakes as a tool and guide for medium- and long-term earthquake risk assessment and resiliency.
]]>Geosciences doi: 10.3390/geosciences14030060
Authors: Federico Spagnoli Teresa Romeo Franco Andaloro Simonepietro Canese Valentina Esposito Marco Grassi Erik Delos Biscotti Patrizia Giordano Giovanni Bortoluzzi
High-definition bathymetry mapping, combined with the measurement of dissolved benthic fluxes and water column biogeochemical properties, allows for a description of new biogeochemical processes around the Panarea Volcanic island. Investigations focused on the CO2 releases from the bottom sea on the east of the Panarea volcanic complex provided insights into the geological setup of the marine area east and south of the Panarea Island. Between the Panarea Island and the Basiluzzo Islet lies a SW-NE-stretching graben structure where a central depression, the Smoking Land Valley, is bounded by extensional faults. Abundant acidic fluids rich in dissolved inorganic Carbon are released on the edges of the graben, along the extensional faults, either diffusely from the seafloor, from hydrothermal chimneys, or at the center of craters of different sizes. The precipitation of iron dissolved in the acidic fluids forms Fe-oxyhydroxides bottom sea crusts that act as a plug, thus preventing the release of the underlying gases until their mounting pressure generates a bursting release. This process is cyclic and results in intermittent gas release from the bottom, leaving extinct craters and quiescent chimneys. The measurement of dissolved benthic fluxes allowed us to estimate the volcanic DIC venting at 15 Mt of CO2 over the past 10,000 years. The fluxes are not distributed homogeneously but rather concentrate along fractures and fault planes, which facilitate their rise to the seafloor. The acidic fluids released affect the chemical properties and structure of the water column through the formation of layers with a lower pH under the pycnocline, which can limit volcanic CO2 release to the atmosphere. Further and continuous monitoring and investigation of the area are needed in order to complete a thorough picture of the variations in fluid releases through time and space. The importance of such monitoring lies in the development of a new method for detecting and quantifying the diffusive dissolved benthic fluxes on a volcanic sea bottom affected by hydrothermal seeps.
]]>Geosciences doi: 10.3390/geosciences14030059
Authors: Takashi Kimura
This study investigated the size–frequency distribution of 512 landslides triggered by heavy rain in July 2018 on Omishima Island, western Japan. Since the island has undergone rapid land use and land cover changes in recent decades, this study statistically examined the impact of past land cover changes on the shape of, and local variability in, the size–frequency distribution using the inverse gamma model. The possible influence of rainfall conditions was also examined. The landslides were classified based on the severity of anthropogenic disturbance and rainfall using a 56-year (1962–2018) land cover trajectory map and hourly rainfall distribution data. The results indicated that the land cover change (mainly forest conversion into farmland and its abandonment) affected the size and frequency of landslides that occurred decades after the disturbance. Although all landslide groups had similar small rollovers (location of probability peak; 0.042–0.075 × 10−3 km2), the scaling exponents of the negative power-law decay were lower for landslides in secondary forest and newly developed farmland (ρ = 1.084–1.231) than in old forest and farmland (ρ = 2.504–2.611). This difference is considered significant compared to general exponent values (ρ = 2.30 ± 0.56), suggesting that farmland development after 1962 caused widespread slope instability, leading to an increase in the proportion of large landslides. By contrast, no clear correlations with rainfall intensity were found, primarily due to complex localised variations in rainfall conditions.
]]>Geosciences doi: 10.3390/geosciences14030058
Authors: Alessandro Croce Giorgio Gatti Antonio Calisi Laura Cagna Donata Bellis Marinella Bertolotti Caterina Rinaudo Antonio Maconi
Asbestos is a term that includes six fibrous mineral phases related to different lung diseases, including asbestosis, lung cancer, and Malignant Pleural Mesothelioma (MPM). Since the last century, these minerals have been widely studied under their mineralogical/chemical and physical aspects with in vivo and in vitro studies to understand the mechanisms of their carcinogenicity. There are several techniques described in the literature, as optical and electron microscopies, for the identification of coated (asbestos bodies, ABs) and uncoated fibers, but only micro-Raman spectroscopy permits a sure characterization of these minerals—and of the related phases—directly in the histological sections of pulmonary parenchyma without any manipulation. In this case, the risk of the loss of associated inorganic phases from asbestos bodies (ABs) and fibers (e.g.: iron or carbonaceous micro-particles) is avoided. Asbestos bodies are produced by the activity of alveolar macrophages with degradation/inactivation of asbestos fibers. Inside the alveolar macrophages, organic and inorganic material settles on the foreign fibers forming an iron-rich proteic and carbonaceous coating. In this study, Variable Pressure Scanning Electron Microscopy with annexed Electron Dispersive Spectroscopy (VP-SEM/EDS) and micro-Raman spectroscopy were applied to the characterization of the phases in the ABs. Characterization of carbonaceous materials (CMs), observed in pristine asbestos phases in previous works, was therefore performed, addressing the micro-Raman laser beam on different points of the asbestos bodies, and Raman mappings on ABs were carried out for the first time. Coupling the data obtained by VP-SEM/EDS and micro-Raman spectroscopy, it was possible to collect information about the iron and carbonaceous phases adhered to the fibers, probably lost during the classical tissue digestion procedures. Information about both mineral and carbonaceous components might be useful to understand the whole structure of “asbestos bodies” and the inflammogenic and carcinogenic effects of the asbestos phases coupled to CMs, that might derive from cigarette smoke or from environmental pollution; this study might be useful to deepen also the possible detrimental role of ABs in the tissues.
]]>Geosciences doi: 10.3390/geosciences14030057
Authors: Sergey Krivoshchekov Andrey Botalov
At present, the study of the oil and gas potential of poorly explored areas of oil and gas basins in the Russian Federation is of great importance due to the possibility of discovering large hydrocarbon accumulations in them. The Vychegda Trough in the north of the Volga–Ural basin is considered to be one of such areas. The research is devoted to the assessment of the oil and gas potential of the Vychegda Trough based on the concept of “petroleum systems”, which is widely used in oil and gas geology. A comprehensive analysis of geological and geophysical, petrophysical and geochemical data was carried out, and modern technologies for studying the oil and gas potential of sedimentary basins were applied: paleotectonic, paleogeographic reconstructions and basin modeling. The results of the research allowed us to determine a sufficiently high potential for the discovery of hydrocarbon accumulations and to identify three potential petroleum systems in the basin section: Riphean, Vendian and Devonian–Permian.
]]>Geosciences doi: 10.3390/geosciences14030056
Authors: Emmanouil Manoutsoglou Ekaterini S. Bei
Sanctuaries devoted to Asclepius were established and operated for almost a thousand years in various Greek and Roman cities throughout the Mediterranean region. The Asclepieion sanctuary in Lentas (formerly known as Ancient Lebena) in Crete was famous for receiving water from a sacred spring. In Ancient Lebena, Levinaion was a famous centre for hydrotherapy, physiotherapy, and a psychiatric hospital. In the present paper, we aim to assess the hydrochemical status of this sacred spring that holds a prominent position in archaeological and historical studies. The main objectives of this study are: Initially, to present supervisory evidence (archaeological, geological, hydrochemical) of an area that was a water resource management model for many centuries, carrying out therapeutic work. The second objective is to present and compare hydrochemical data in the last century, i.e., from 1915 to 2021. The third objective is to highlight and warn of an incipient saltwater intrusion in the area along the Lentas coast. The fourth objective is to propose an alternative and sustainable form of water resources management in the region that requires the study and rational utilization of the sporadic small water springs in the region. Our study focuses on a basic hydrochemical analysis of spring and borehole water in the remains of Levinaion in the Lentas region, and their comparison with sparse historical data of the sacred spring water, aiming to interpret the impact of the changes in the spring water resources that occurred in recent decades due to urban modernization. Our results highlight (i) visible fluctuations in chemical composition of borehole water samples; (ii) a neutral to alkaline pH in borehole waters and an alkaline pH in spring waters; (iii) undetectable arsenic in Lentas borehole water, unlike historical data of Lentas spring water; (iv) low values of dissolved radon in Lentas borehole water and the spring water of Kefalovrysa; and (v) a timeless constant and hypothermic nature of the water of both the sacred spring and borehole of Lentas, and also of the Kefalovrysa spring. The recorded historical data, i.e., from 1915 to 1957, due to the absence of substantial anthropogenic activity in the area, can be used as reference values (natural background levels, NBLs) for the Lentas area. Our findings emerge with the need to bring again the flowing spring water of the sacred spring of Lentas in its original form through sustainable management and re-discover its beneficial therapeutical effects.
]]>Geosciences doi: 10.3390/geosciences14030055
Authors: Lit Yen Yeo Fredrik Phangkawira Pei Gee Kueh Sue Han Lee Chung Siung Choo Dongming Zhang Dominic Ek Leong Ong
Pipe jacking is a trenchless technology used to install buried pipelines, such as sewer lines in wastewater management systems. Existing mechanistic approaches based on geomaterial strength parameters (i.e., friction angle and apparent cohesion) can provide an estimation of the potential jacking forces during construction. However, extracting intact rock cores for strength characterisation is challenging when dealing with highly weathered ‘soft rocks’ which exhibit RQD values of zero. Such was the case for a pipe jacking drive traversing the highly weathered lithology underlying Kuching City, Malaysia. Furthermore, mechanistic approaches face limitations during construction when jacking forces are dependent on operation parameters, such as jacking speed and lubrication. To address these knowledge gaps, the primary objectives of this study are the development of rock strength parameters based on in situ pressuremeter testing for the purpose of estimating jacking forces. Furthermore, this study investigates the influence of various pipe jacking operation parameters, with a particular focus on their impact on jacking forces in weathered ‘soft rocks’. To achieve this, a novel deep learning model with an attention mechanism is introduced. The proposed methods of rock strength parameters derived from pressuremeter testing and the utilisation of deep learning will help to provide insights into the key factors affecting the development of jacking forces. This paper successfully shows the use of in situ pressuremeter testing in developing Mohr–Coulomb (MC) parameters directly from the site. In addition, the developed deep learning model with an attention mechanism successfully highlights the significance of pipe jacking operation parameters with an accuracy of 88% in predicting the jacking forces.
]]>Geosciences doi: 10.3390/geosciences14020054
Authors: Maciej Gniewosz Agnieszka Stopkowicz Marek Cała
The hazards of gaseous geodynamic phenomena and rockbursts are among the most challenging to assess and classify. This perception arises from both a review of the literature and an examination of available instructions and regulations in underground mining facilities. The hazard of gaseous geodynamic phenomena in Polish copper ore mines only appeared in 2009, whereas these phenomena occur and are commonly described in other mining countries. In Polish copper ore mines, due to the room and pillar system in fields with lengths of about 460 m, very often parallel to neighboring fields, which together give a length of about 900 m, it is difficult to identify the location of gas traps due to the large size of the area. This paper presents an analysis of the influence of the velocity of the excavation on the possibility of escalating or reducing the described mining hazards. An analysis of the impact of excavation velocity on the state of gaseous geodynamic and roof fall hazards was conducted for two mining fields. For the considered mining fields, the hypothesis was formulated that an excavation velocity greater than or equal to 17 m/month positively influences a reduction in both gaseous geodynamic and roof fall hazards.
]]>Geosciences doi: 10.3390/geosciences14020053
Authors: Paolo Paronuzzi Dario Fedrigo Alberto Bolla
This work investigates the rainfall infiltration process within homogeneous and stratified colluvial deposits caused by short (1–3 h) and intense (40–90 mm/h) rainfall, using both analytical and numerical infiltration modelling. The findings of the investigation demonstrate that the classic Green–Ampt model can be employed effectively to study homogeneous colluvial covers with permeability equal to or lower than kw = 10−5 m/s and that are subject to a 1 h rainfall with intensity I ≥ 45–50 mm/h. In these circumstances, a top-down saturation front forms within the colluvial deposit, leading to the saturation of a 70–100 cm-thick layer. This critical condition occurs every 5–10 years in the mountain area of the Friuli Venezia Giulia Region (NE Italy), which corresponds to a lower return period of critical hydrologic events when compared with other mountain basins in the Alps due to the higher initial degree of saturation characterising colluvial covers in this area (70–95%). When analysing stratified colluvial covers, the Dagan–Bresler approximate model, as well as the numerical modelling, emphasised the strong influence that abrupt variations in the permeability of the various soil layers have on the infiltration process at depth. In particular, the presence of a top organic soil horizon that is rich in macro-pores and is characterised by a higher permeability (k = 10−4 m/s) actually reduces the possibility of surficial ponding, which is the basic condition of the “piston” models. The highly permeable top soil allows for a rapid downward infiltration up to contact with the underlying colluvial material, which is less permeable (k = 10−5 m/s). Therefore, a perched water table forms starting from the organic soil–colluvium interface, originating pore–water overpressures within the colluvial deposit, with maximum values in the order of 5–10 kPa.
]]>Geosciences doi: 10.3390/geosciences14020052
Authors: Mohammad Ezazi Ebrahim Ghorbani Ali Shafiei Ebrahim Sharifi Teshnizi Brendan C. O’Kelly
Hydraulic fracturing (HF) is the primary choice for stimulating petroleum reservoirs. Rock tensile strength and brittleness are crucial parameters required for screening candidate reservoirs and in designing successful HF operations. However, in situ and laboratory determinations of the hydraulic tensile strength (HTS) of rock can prove problematic. Alternatively, the HTS could be estimated from the rock brittleness once a reliable relationship has been established between them. Accordingly, this paper investigates the correlations between the HTS, as measured using laboratory hydraulic fracture tests, and ten strength-based brittleness indices (BIs) selected from the research literature. The primary inputs for computing these BIs are uniaxial compressive strength (UCS) and the Brazilian tensile strength (BTS), which are typically measured for most projects using standard laboratory rock mechanics tests or obtained from log data. For the purposes of this experimental investigation, intact rock core samples were obtained from a carbonate–dolomite formation in Iran, comprising eight distinct geomechanical units, with measured values of UCS, BTS, and HTS ranging 29.7–162.2, 1.93–12.23, and 7.20–20.63 MPa, respectively. The measured HTS was found to directly correlate with the UCS, BTS, and Young’s modulus, and inversely correlated with the rock porosity. Seven of the ten investigated BIs correlated with the measured HTS over 69% (R2 ≥ 0.69). In particular, the BI expressions developed by Yagiz and Gokceoglu, Ghadernejad et al., and Khandelwal et al. exhibited relatively strong correlations with the measured HTS (producing R2 values of 0.94, 0.87, and 0.86, respectively), suggesting that these three HTS–BI correlations could be used to provide preliminary HTS estimates for the investigated carbonate–dolomite formation in Iran. This work adds to a database that can be expanded to include other geographical regions for providing useful information about the selection of a suitable site or reserve for conducting HF operations.
]]>Geosciences doi: 10.3390/geosciences14020051
Authors: Anselme Muzirafuti
Tabular Middle Atlas of Morocco holds the main water reservoir that serves many cities across Morocco. Dolomite and limestone are the most dominant geologic formations in this region in which water resources are contained. The recent studies conducted to evaluate the quality of this water suggest that it is very vulnerable to pollutants resulting from both anthropogenic and natural phenomenon. High and very high-resolution satellite imagery have been used in an attempt to gain a better understanding of this karstic system and suggest a strategy for its protection in order to reduce the impact of these phenomenon. Based on the surface reflectance of land cover benchmarks, the karstic system has been horizontally delineated, as well as regions with intense human activities. Using band combination in the portion of the infrared, shortwave infrared, and visible parts of the electromagnetic spectrum, we identified bare lands which have been interpreted as carbonate rocks, clay minerals, uncultivated fields, basalts rocks, and built-up areas. Other classes such as water and vegetation have been identified. Carbonate rocks have been identified as areas with a high rate of water infiltration through their fracture system. Using a Sobel operator filter, these fractures have been mapped and their results have revealed new and existing faults in two major fracture directions, NE-SW and NW-SE, where NE-SW is the preferable pathway for surface water infiltration towards the groundwater reservoir, while the NW-SE direction drains groundwater from the Cause to the basin of Saiss. Over time, the infiltration of surface water through fractures has contributed to a gradual erosion of the carbonate rocks, which in turn developed karst landforms. This karst system is vulnerable due to the flow of pollutants in areas with shallow sinkholes. Using GDEM imagery, we extracted karst depressions, and their analysis shows that they are distributed along the fracture system and many of them were located on curvilinear or linear axes along the NE-SW fracture direction. We found also dolines scattered in areas with a high intensity of fractures. This distribution has been validated by both on-the-ground measurements and very high-resolution satellite images, and depressions of different forms and shapes dominated by dolines, poljes, lapiez, and avens have been identified. We also found many water springs with a highly important water output, such as the Ain Maarrouf water spring. The aim of this study is to enhance the understanding of the hydrogeological system of TMA, to improve the existence of the fracture database in the Cause of Agourai, and to establish a new morpho-structural picture of the Ain Maarrouf water spring.
]]>Geosciences doi: 10.3390/geosciences14020050
Authors: Thomas Martin Hearn
This paper presents a study of global Rayleigh wave attenuation and group velocity at a period of around 20 s using data from the International Seismological Centre (ISC) bulletin. Rayleigh waves at this period are sensitive to the crustal structure beneath continents and the uppermost mantle beneath oceans. Tomographic imaging reveals strong continental-ocean contrasts due to this. Oceanic group velocities are high but vary with seafloor depth, while oceanic attenuation shows mid-ocean ridges. Subduction zone regions display high attenuation but little velocity reduction, indicating scattering attenuation. Low attenuation regions are associated with the Earth’s major cratonic regions, but there are no associated velocity changes. This implies that intrinsic attenuation is low and scattering dominates. Cratonic crustal scatterers have been annealed. A new surface wave magnitude scale is constructed that is valid from near-source to near-antipode distances.
]]>Geosciences doi: 10.3390/geosciences14020049
Authors: Ilaria Spassiani Matteo Taroni
A seismic hazard can be quantified by using probabilities. Modern seismic forecasting models (e.g., Operational Earthquake Forecasting systems) allow us to quantify the short-term variations in such probabilities. Indeed these probabilities change with time and space, in particular after strong seismic events. However, the short-term seismic hazard could also change during seismic swarms, i.e., a sequence with several small-/medium-sized events. The goal of this work is to quantify these changes, using the Italian Operational Earthquake Forecasting system, and also estimate the variations in the Gutenberg–Richter b-value. We focus our attention on three seismic swarms that occurred in Central Italy in October–November 2023. Our results indicate that short-term variations in seismic hazard are limited, less than an order of magnitude, and also that b-value variations are not significant. Placing our findings in a more general context, we can state that according to currently available models and catalogs, the occurrence of seismic swarms does not significantly affect the short-term seismic hazard.
]]>Geosciences doi: 10.3390/geosciences14020048
Authors: Chrysanthos Botziolis Nicolina Bourli Elena Zoumpouli Penelope Papadopoulou Nikolaos Dimopoulos Andriana Kovani Panagiotis Zelilidis Diamantina Christina Aspioti George Iliopoulos Avraam Zelilidis
This study delves into the sedimentation mechanisms governing mud deposits in shallow marine and tidal environments, with a particular focus on elucidating the versatile therapeutic applications of these muds. This research provides valuable insights for optimizing the selection of mud as a cosmetic resource that can positively influence human health and well-being by utilizing a comprehensive analysis involving CaCO3, TOC, grain size, and statistical parameters across six outcrops situated on the Kefalonia and Corfu islands. The research reveals that the CaCO3 content of mud deposits on both islands is comparable. Despite the average value (26.71%) significantly exceeding the recommended value (10%) for optimal plasticity, no discernible impact on the mechanical behavior and plasticity of the clay was observed, rendering it a neutral quality criterion. Notably, the TOC content is higher on Corfu Island, suggesting its potential superiority for mud therapy. However, all samples exhibit a TOC content (<0.77%) considerably below the threshold required (2–5%) for material maturation in mud therapy. Consequently, an enrichment of samples with organic matter is imperative. The application of statistical parameters, analyzed through graphical methods, facilitated the creation of various bivariate diagrams, offering insights into the prevailing environmental conditions during deposition. Linear and multigroup discriminant analyses categorize two sediment types: a unimodal type, characterized by mud grain-size dominance, deposited in a shallow water environment, and a bi-modal type, featuring mud and sand content, deposited in a tidal-affected environment. This classification underscores the potential of shallow marine muds (Kefalonia Island) for therapeutic use, given their optimal grain size. In contrast, the tidal mud (Corfu Island), while also suitable for mud therapy, necessitates processing as a cosmetic product to minimize sand content, as coarser fractions may induce skin irritations or injuries.
]]>Geosciences doi: 10.3390/geosciences14020047
Authors: Samuel Erzuah Ingebret Fjelde Aruoture Voke Omekeh
Minerals are the chief constituents of rocks and have varied properties, such as the surface area, surface charge, site density, etc. Hence, numerous interactions are bound to occur in a reservoir during rock–fluid (i.e., rock, crude oil and brine) interactions. This study seeks to assess the role of the mineralogical composition in the wettability of sandstone rocks (SRs) and mineral mixture (MM) using both surface complexation modeling (SCM) and a flotation test. From the considered sandstone rocks, both the experimental results and the simulated counterparts revealed that the SRs were preferentially hydrophilic. For the MM, when the mass fraction of the hydrophobic mineral was increased, the affinity of the MM became slightly hydrophobic, and vice versa. For the dominant sandstone reservoir rock minerals with predominantly negatively charged surfaces, negligible oil adsorption took place due to the interfacial repulsive forces at the oil–brine and mineral–brine interfaces. For the MM with low calcite content, the wetting preference was influenced by the mineral with a prominent surface area. Our developed model portrayed that the main mechanism of oil adhesion onto sandstone minerals was divalent cation bridging. Nonetheless, adhesion of carboxylate (>COO−) onto the illite, montmorillonite and calcite sites also took place, with the latter being more pronounced.
]]>Geosciences doi: 10.3390/geosciences14020046
Authors: Alexander Fekete Beate Rhein
The floods in 2021 in Germany laid bare the need to better integrate volunteers into official disaster management. An online survey with 1767 valid interviews after the floods in July 2021 reveals the shared experiences of professional and non-professional groups. Communication and coordination problems are the main results of the survey analysis. Overall satisfaction was a bit lower for the volunteers than for the professionals. The behavior of the superiors could have been more satisfactory. The preparation and opportunity for reflection could have been better after the operation. The information provision before and during the flood operation could have been more satisfactory. Worries were higher about elderly persons, and misinformation was a perceived danger. Problems experienced in the flood operations ranged from psychological stress to hygiene, self-endangerment, assignment of tasks, and misinformation, both from the media and official sources. Infrastructure-related problems included electricity, water, communication lines, roads, and rail. The suggestions for improvements ranged from communication and information about warnings and behavior to persons that transfer knowledge between organizations, digital exchange platforms, and exchange between countries.
]]>Geosciences doi: 10.3390/geosciences14020045
Authors: Joan Cecilia Casila Howard Lee Andres Soufiane Haddout Katsuhide Yokoyama
Following the eruption of the Taal Volcano in January 2020 and its continuous signs of unrest in the preceding years, this study delves into the investigation of sediment transport in the Pasig River, Philippines. The historical data of total suspended solids (TSS) and arsenic indicated a notable increase starting from the year 2020. The field measurements were conducted in February and March of 2022, two years after the eruption. Due to the observed homogeneity in the river’s mixing, a refined 1D sediment transport model was developed. In this study, HEC-RAS modeling software was employed. The calibration process using the Laursen transport function yielded an impressive R2 value of 0.9989 for the post-eruption model. This predictive accuracy underscores the robustness of the developed model. The study’s scope was further expanded by creating a model for February 2020, incorporating water quality data gathered by the Pasig River Coordinating and Management Office. The model simulation results showed peak TSS values of 120.63 mg/L and 225.15 mg/L in February 2022 and February 2020, respectively. The results of the study highlight the probable impact of geological events on sediment dynamics within the Pasig River, which could help manage and sustain ongoing river improvements.
]]>Geosciences doi: 10.3390/geosciences14020044
Authors: Sudan Shakya Christoph Schmüdderich Jan Machaček Luis Felipe Prada-Sarmiento Torsten Wichtmann
Supervised machine learning (ML) techniques have been widely used in various geotechnical applications. While much attention is given to the ML techniques and the specific geotechnical problem being addressed, the influence of sampling methods on ML performance has received relatively less scrutiny. This study applies supervised ML to the strain-dependent slope stability (SDSS) method for the prediction of the factor of safety (FoS) using hypoplasticity. It delves into different sampling strategies for training the ML model, emphasizing predictions of soil behavior in lower stress ranges. A novel sampling method is introduced to ensure a more representative distribution of samples in these ranges, which is challenging to achieve through traditional sampling approaches. The ML models were trained using traditional and modified sampling methods. Subsequently, slope stability analyses using SDSS were conducted with ML models trained from six different sampling methods. The results illustrate the impact of sampling methods on the FoS. Besides a noticeable improvement in predictions of shear stresses within the lower stress ranges, a decisive effect on the overall FoS was observed as well.
]]>Geosciences doi: 10.3390/geosciences14020043
Authors: Karin Goldberg Lucas Goldberg Da Rosa
The complex controls on the accumulation of organic-rich rocks remain elusive, despite their economic importance as source rocks and unconventional reservoirs, partially due to the multitude of factors that may impact production and preservation of organic matter in sediments. The complexity of Earth systems is comparable to the intricacies of Economics, and application of statistical and econometrics methods and models to analyze geological data may assist interpretation of the processes controlling organic burial. Chemical indices calculated for mudrock datasets from modern sediments and the Woodford Formation were used as proxies for detrital input, primary productivity, redox conditions, and upwelling, and a series of statistical analyses were run to test whether these methods were useful to discriminate different depositional conditions and establish the controls on total organic carbon (TOC) in the sediments. Model results showed that chemical proxies reliably predict not only TOC but also indicate correlations between indices. Our results suggest that detrital input, primary productivity and bottom-water anoxia are relevant drivers of organic content in the sediments, but the first two appear to have a more significant role in organic burial, illustrating the usefulness of these methods to assess depositional parameters in organic-rich rocks.
]]>Geosciences doi: 10.3390/geosciences14020042
Authors: Emilia Damiano Maria Assunta Fabozzi Paolo Maria Guarino Erika Molitierno Lucio Olivares Roberto Pratelli Marco Vigliotti Daniela Ruberti
In northern Campania (Southern Italy), the historic center of many towns is characterized by the widespread presence of cavities in the subsoil, excavated over the centuries for quarrying tuff blocks for buildings, along with cathedrals, churches and chapels. A singular feature of these places of worship is, in fact, the presence of a wide and frequently connected network of underground cavities and tunnels, which were used for hydraulic, religious or connecting purposes. The cavity network is often unknown, abandoned or even buried, thus representing a risk for their susceptibility to sinkholes. Such elements are important as cultural heritage of inestimable value and as attractors for tourism; for this reason, the multidisciplinary study conducted on a place of worship in the Caserta area is illustrated herein: the Cloister of Sant’Agostino, in Caserta (XVI century CE). A geological and geotechnical characterization of the subsoil was performed at first. A laser scanner survey of the accessible cavities and the external churchyard was carried out. The resulting 3D model of the underground sector allowed for a clear understanding of the room size, their location, the levels and the path of the corridors. To understand the extension and layout of the crypts, Electrical Resistivity Tomography (ERT) surveys were undertaken in the surrounding areas. The analysis of the ERT measurements revealed some anomalies that could be ascribed to unknown structures (crypts). Finally, numerical methods were applied to estimate the stress state of the soft rocks and the potential areas of crisis, with preliminary assessments of the influence of the presence of cavities on the stability of the subsoil. The results allowed us to improve the knowledge of the study site and provide useful data for the planning of future targeted investigations, underlining how integrated research between applied disciplines can provide indispensable support both in the management and mitigation of geological risks in urban areas and in the sustainable reuse of hypogea.
]]>Geosciences doi: 10.3390/geosciences14020041
Authors: Victoria Ershova Andrei Prokopiev Daniel Stockli
Provenance study plays an important role in paleogeographic and tectonic reconstructions. Detrital zircons are commonly used to identify sediment provenance; however, a wide range of detrital zircon ages in clastic rock often represent a fingerprint of reworked older terrigenous successions rather than ages of magmatism and metamorphism in the provenance area. This study focuses on the provenance of detrital rutile grains in the Triassic–Jurassic sandstones from Franz Josef Land and shows the importance of multiproxy approaches for provenance studies. Trace element data demonstrate that most rutile grains were sourced from metapelitic rocks, with a subordinate population having a metamafic origin. The Zr-in-rutile thermometer and U-Pb geochronology suggest that detrital rutile grains were predominantly derived from rocks that underwent amphibolite facies metamorphism during the Paleozoic era, with a predominance of the Carboniferous–Permian ages. Therefore, we suggest that the provenance area for the studied sandstones on Franz Josef Land has a similar geological history to the Taimyr region and Severnaya Zemlya archipelago. We propose that this crustal domain extends across the Kara Sea and forms the basement to the north and east of FJL, representing a proximal provenance for the studied Mesozoic terrigenous rocks. This domain experienced both Middle–Late Ordovician and Carboniferous–Permian metamorphism. The comparison of U-Pb dating and the geochemistry of rutile, U-Th/He, and U-Pb dating of zircons showed that detrital rutiles are the powerful toll in provenance restoration and can give additional constrains when a provenance area locates within collisional-convergent settings.
]]>Geosciences doi: 10.3390/geosciences14020040
Authors: Mandip Banjara Amrit Bhusal Amrit Babu Ghimire Ajay Kalra
Land use and land cover (LULC) change is one of the primary contributors to hydrological change in urban watersheds and can potentially influence stream flow and flood volume. Understanding the impacts of LULC change on urban hydrological processes is critical to effective urban water management and minimizing flood risks. In this context, this study aims to determine the impacts of LULC change on hydrological response in a fast transitioning watershed for the predicted years of 2050 and 2080. This research employs the hybrid land use classification technique, Cellular Automata–Markov (CA–Markov) model to predict land use changes, utilizing land use data from 2001, 2013, and 2021. Additionally, it incorporates a calibrated, event-specific hydrologic model known as the Personal Computer Storm Water Management Model (PCSWMM) to assess alterations in hydrological responses for storm events of various magnitudes. The findings indicate a transition of the watershed into an urbanized landscape, replacing the previous dominance of agriculture and forested areas. The initial urban area, constituting 11.6% of the total area in 2021, expands to cover 34.1% and 44.2% of the total area by 2050 and 2080, respectively. Due to the LULC changes, there are increases in peak discharge of 5% and 6.8% and in runoff volume of 8% and 13.3% for the years 2050 and 2080 for a 100-year return period storm event. Yet, the extent of these changes intensifies notably during storm events with lower return periods. This heightened impact is directly attributed to the swift urbanization of the watershed. These results underscore the pressing necessity to regulate LULC change to preserve the hydrological equilibrium.
]]>Geosciences doi: 10.3390/geosciences14020039
Authors: Davide Pistillo Emanuele Colica Sebastiano D’Amico Daniela Farrugia Federico Feliziani Luciano Galone Roberto Iannucci Salvatore Martino
Different engineering geological and geophysical investigations were performed at the Sopu promontory in the island of Gozo (Malta), involved in an impressive lateral spreading process due to the superimposition of a stiff limestone (ULC) on a ductile clay (BC). The applied techniques include: traditional geological and engineering geological surveys, unmanned aerial vehicles (UAV) survey, electrical resistivity tomography (ERT) survey, ground-penetrating radar (GPR) investigations, single-station seismic ambient noise measurements, and array seismic ambient noise measurements. The integration of the obtained results allowed us to reconstruct a subsoil model of the promontory that includes features related to the local geology of the slope and to the landslide process, as well as to define a conceptual model that describes the main evolution phases of the expansion process. The presence of back-tilted rock blocks with no features of polarization of Rayleigh waves evidenced the different failure mechanism of the rigid UCL plateau at the Sopu promontory with respect to the Selmun promontory, located in the close island of Malta, where the lateral spreading due to the same geological setting tends to produce unstable rock blocks with a toppling mechanism. This result encourages further future observations and analyses of this topic.
]]>Geosciences doi: 10.3390/geosciences14020038
Authors: Yao Li Roberto Alves Sai Vanapalli Gilson Gitirana
The soil–water characteristic curve (SWCC) is widely used as a tool in geotechnical, geo-environmental, hydrology, and soil science fields for predicting and interpreting hydro-mechanical behaviors of unsaturated soils. Several previous studies focused on investigating the influence of initial water content, stress history, temperature, and salt content on the SWCC behavior. However, there is still limited understanding to be gained from the literature on how we can systematically incorporate the influence of complex thermo-hydro-mechanical-chemo (THMC) effects into interpreting and predicting the behavior of unsaturated soils. To address that knowledge gap, in this study, the coupled influence of temperature, initial stress state, initial density, soil structure, and chemical solution effects was modeled using established SWCC equations from the literature. The methodology for incorporating the coupled effects of these influential factors is presented herein. Furthermore, we evaluated the SWCC models proposed in this study, enabling us to provide a comprehensive discussion of their strengths and limitations, using the published SWCC data from the literature. The developments outlined in this paper contribute toward facilitating a rigorous approach for analyzing the THMC behaviors of unsaturated soils.
]]>Geosciences doi: 10.3390/geosciences14020037
Authors: Debayan Ghosh Aritra Banerjee Anand J. Puppala Prince Kumar
Climate change is known to cause alterations in weather patterns and disturb the natural equilibrium. Changes in climatic conditions lead to increased environmental stress on embankments, which can result in slope failures. Due to wetting–drying cycles, expansive clayey soil often swells and shrinks, and matric suction is a major factor that controls the behavior. Increased temperature accelerates soil evaporation and drying, which can cause desiccation cracks, while precipitation can rapidly reduce soil shear strength. Desiccated slopes on embankments built with such soils can cause surficial slope failures after intense precipitation. This study used slope stability analysis to quantify how climate-change-induced extreme weather affects embankments. Historic extreme climatic events were used as a baseline to estimate future extremes. CMIP6 provided historical and future climatic data for the study area. An embankment was numerically modeled to evaluate the effect on slope stability due to the precipitation change induced by climate change. Coupled hydro-mechanical finite element analyses used a two-dimensional transient unsaturated seepage model and a limit equilibrium slope stability model. The study found that extreme climatic interactions like precipitation and temperature due to climate change may reduce embankment slope safety. The reduction in the stability of the embankment due to increased precipitation resulting from different greenhouse gas emission scenarios was investigated. The use of unsaturated soil strength and variation of permeability with suction, along with the phase transition of these earthen embankments from near-dry to near-saturated, shows how unsaturated soil mechanics and the hydro-mechanical model can identify climate change issues on critical geotechnical infrastructure.
]]>Geosciences doi: 10.3390/geosciences14020036
Authors: Anthony R. Fiorillo Paul J. McCarthy Grant Shimer Marina B. Suarez Ryuji Takasaki Tsogtbaatar Chinzorig Yoshitsugu Kobayashi Paul O’Sullivan Eric Orphys
The Nanushuk Formation (Albian–Cenomanian) crops out over much of the central and western North Slope of Alaska, varying from ≈1500 to ≈250 m thick from west to northeast. The Nanushuk Formation records an inter-tonguing succession of marine and nonmarine conglomerate, sandstone, mudstone, and coal. These rock units comprise the Kukpowruk and Corwin formations of the former Nanushuk Group, respectively. Work presented here is centered in the foothills of the DeLong Mountains along the Kukpowruk River, from an area west of Igloo Mountain in the Coke Basin to the Barabara Syncline, approximately 80 km to the north. A radiometric date recovered from a tuff in our study area suggests a Cenomanian age for at least some of these rocks. Outcrops along the Kukpowruk River contain a well-preserved fossil flora previously recovered from marine, marginal marine, and terrestrial sediments. Our own work focuses on detailed measured sections of terrestrial rocks, interpretation of sedimentary facies and facies associations, and documentation of fossil vertebrates. Eight facies associations are identified in the study area that together are interpreted to represent meandering fluvial and upper delta plain environments. Plant fossils are common and include standing tree trunks up to 58 cm in diameter at some locations. Approximately 75 newly discovered tracksites, and a heretofore unknown, rich fossil vertebrate ichnofauna, are present. The ichnofaunal assemblage includes evidence of small and large theropod dinosaurs (including birds) and bipedal and quadrupedal ornithischian dinosaurs. Approximately 15% of the dinosaur ichnofauna record is represented by fossil bird tracks. Wood fragments from the Nanushuk Formation were analyzed for their carbon isotopic composition to relate δ13C to mean annual precipitation. Samples averaged −26.4‰ VPDB, suggesting an average MAP of 1412 mm/year. This record of increased precipitation in the Nanushuk Fm. during the mid-Cretaceous provides new data that supports global precipitation patterns associated with the Cretaceous Thermal Maximum. This work provides an important framework for much-needed further paleoecological and paleoclimatic analyses into greenhouse conditions in the terrestrial Cretaceous Arctic during this important window in time.
]]>Geosciences doi: 10.3390/geosciences14020035
Authors: Mathieu Nguyen Jean-Baptiste Thomas Ivar Farup
We explored imaging methods to perform in situ field measurements of physical correlates of the visual appearance of snow. Measurements were performed at three locations in Norway between February and March 2023. We used a method to estimate the absorption and scattering coefficients of snow using only one measurement of reflectance captured by the Dia-Stron© TLS850 translucency meter. We also measured the sparkle indicators (contrast and density of sparkle spots) from digital images of snow. The contrast of sparkle spots can be defined as the median value of all the pixels identified as sparkle spots by an algorithm, and the density of sparkle spots is the number of sparkle spots in a selected area of the image. In the case of the sparkle of the snow surface, we found that there is a potential to use the sparkle indicators for classifying the grain types, but it requires a larger data set coupled with expert labelling to define the type of snow. For the absorption and scattering properties, the measurements confirm the fact that snow is a weakly absorptive and highly scattering material when modelling light interactions in the snow. No correlation between the optical properties and sparkle could be found in our data.
]]>Geosciences doi: 10.3390/geosciences14020034
Authors: Yusheng Jiang Zaid Alajlan Claudia Zapata Xiong Yu
Geotextile offers numerous benefits in improving pavement performance, including drainage, barrier functionality, filtration, and reinforcement. Wicking geotextile, a novel variant in this category, possesses the intrinsic ability to drain water autonomously from soils. This paper details the development and application of a comprehensive multiphysics model that simulates the performance of wicking geotextile within a pavement system under freezing climates. The model considers the inputs of various environmental dynamics, including the impact of meteorological factors, groundwater levels, ground heat, and drainage on the pavement system. The model was firstly validated using field data from a long-term pavement performance (LTPP) road section in the cold region. It was subsequently applied to assess the impacts of wicking geotextile if it was installed on the road section. The model simulated the coupled temporal and spatial variations in soil moisture content and temperature. The simulation results demonstrated that wicking geotextile would create a suction zone around its installation location to draw water from surrounding soils, therefore reducing the overall unfrozen water content in the pavement. The results also showed that the installation of wicking geotextile would delay the initiation of frost heave and reduce its magnitude in cold region pavement.
]]>Geosciences doi: 10.3390/geosciences14020033
Authors: Mei Li Hongzhu Yan Yongxian Zhang
In this study, 117,718 ionospheric perturbations, with a space size (t) of 20–300 s but no amplitude (A) limit, were automatically globally searched via software utilizing ion density data measured by the DEMETER satellite for over 6 years. The influence of geomagnetic storms on the ionosphere was first examined. The results demonstrated that storms can globally enhance positive ionospheric irregularities but rarely induce plasma variations of more than 100%. The probability of PERs with a space size falling in 200–300 s (1400–2100 km if a satellite velocity of 7 km/s is considered) occurring in a geomagnetically perturbed period shows more significance than that in a quiet period. Second, statistical work was performed on ion PERs to check their dependence on local time, and it was shown that 24.8% of the perturbations appeared during the daytime (10:30 LT) and 75.2% appeared during the nighttime (22:30 LT). Ionospheric fluctuations with an absolute amplitude of A < 10% tend to be background variations, and the percentages of positive perturbations with a small A < 20% occur at an amount of 64% during the daytime and 26.8% during the nighttime, but this number is reversed for mid–large-amplitude PERs. Large positive PERs with A > 100% mostly occurred at night and negative ones with A < −100% occurred entirely at night. There was a demarcation point in the space size of t = 120 s, and the occurrence probabilities of day PERs were always higher than that of nighttime ones before this point, while this trend was contrary after this point. Finally, distributions of PERs according to different ranges of amplitude and space scale were characterized by typical seasonal variations either in the daytime or nighttime. EIA only exists in the dayside equinox and winter, occupying two low-latitude crests with a lower Np in both hemispheres. Large WSAs appear within all periods, except for dayside summer, and are full of PERs with an enhanced amplitude, especially on winter nights. The WN-like structure is obvious during all seasons, showing large-scale space. On the other hand, several magnetically anomalous zones of planetary-scale non-dipole fields, such as the SAMA, Northern Africa anomaly, and so on, were also successfully detected by extreme negative ion perturbations during this time.
]]>Geosciences doi: 10.3390/geosciences14020032
Authors: Juan Antonio Ramos-Sánchez Sergio A. Díaz René Sebastián Mora-Ortiz Gabriel Polanco-Sotomayor Francisco Magaña-Hernández
Seismic risk management in urban areas requires accurate prediction of the expected seismic hazard. The seismic design standards in the world provide the seismic design spectra (DS). These are crucial for estimating seismic forces on a structure, are typically derived from theoretical models in deterministic or probabilistic seismic hazard studies, especially for bedrock soils. Characterizing soil dynamic amplification frequencies or periods is necessary to establish site-specific design spectra (DSsite). Geotechnical and geophysical studies, along with environmental vibration records, determine soil stratigraphy characteristic features and their dominant frequency or period. These parameters improve our understanding of seismic wave behavior from bedrock to surface soil during earthquakes. This article details the utilization of geotechnical, geophysical studies, and environmental vibration records to estimate DSsite in accordance with Mexican seismic regulation and examines the cost–benefit aspects of using the Dssite in optimizing the structural design of a medium-rise steel building in southeastern Mexico, characterized by soft soil and a moderate seismic hazard. The case study demonstrates an 18% cost savings in the structural elements of the building by employing the DSsite with more rational spectral ordinates for study site.
]]>Geosciences doi: 10.3390/geosciences14020031
Authors: Chang Zhong Xiaoyin Tang Jiaqi Wang
The eastern Qaidam Basin (EQB), along with its surrounding orogenic belts, witnessed complicated tectonic movements in the period from the late Paleozoic to the early Mesozoic. As strategic succeeding strata, the Carboniferous strata (CST) in the EQB have gradually become a research hotspot in recent years. However, the question of how tectonism controlled the tempo-spatial evolution of the CST has yet to be studied. To resolve these issues, we collated statistics related to unconformities, seismic interpretation, and basin modeling in this study. The results show that the structure of the CST was mostly controlled by NNE-striking faults, namely the Zongjia and Ainan Fault, in the period from the Carboniferous to the Triassic time. During the Carboniferous time, the sedimentation of the CST was controlled by medium-high angle potential normal faults. The CST experienced two stages of tectonic subsidence and subsequent burial: the highest average subsidence and burial rate of 45 m/Ma and 12 m/Ma occurred at 340~285 Ma, decreasing to 15 m/Ma and 7.5 m/Ma between 305 Ma and 250 Ma. However, the maximum burial (~5500 m) took place at ~250 Ma. From the end of the late Permian to the late Triassic (254~195 Ma), the overall exhumation rate of the CST has averaged 38.71 m/Ma, and 75 m/Ma in the southern margin of the Huobuxun Depression. The CST near the piedmont margins of the EQB suffered essential denudation at 254~195 Ma, resulting in small amounts of the residual CST. In these areas, the CST were deformed with a steepening dip during this time and were characterized by the combinations of syncline-anticlinal asymmetric folds with the high-angle interlimb. These findings indicated that the tempo-spatial evolution of the CST was possibly influenced by the sedimentary and tectonic transition, and was a combined response to Paleo-Tethys Ocean subduction, and arc-continental collisions since the late Paleozoic to early Mesozoic periods.
]]>Geosciences doi: 10.3390/geosciences14020030
Authors: Stine Detjens Sonja B. Grimm Aslı Oflaz Dennis Wilken Tina Wunderlich Wolfgang Rabbel Berit V. Eriksen
The Lieth Moor area, located in the district of Pinneberg, Schleswig-Holstein, Germany, is a hotspot of Late Palaeolithic settlement activity. The exceptional abundance of archaeological sites is commonly attributed to the presence of a large palaeolake. However, in the Weichselian Late glacial, there were numerous large lakes in Schleswig-Holstein. Thus, a well-founded explanation for the find concentration in Lieth Moor is still lacking, and forming a research desideratum until today. To improve our understanding of this Late Pleistocene landscape and its appeal to hunter–gatherer groups of that time, we conducted a large-scale archaeogeophysical study focusing on a possible ford of the potential palaeolake. We employed Ground-Penetrating Radar and Electromagnetic Induction measurements, supplemented by existing legacy drill-probing data, to identify and map limnic gyttja (organic lake mud) sediments and their spatial distribution within the area. The findings of our study indicate that during the Late Pleistocene to Early Holocene, the Lieth Moor area comprised a cluster of small ponds rather than a continuous lake. These ponds likely interconnected during periods of increased water levels. The presence of dry islands within the region corresponds with archaeological evidence, suggesting that Late Palaeolithic communities visited some of these islands. The absence of the previously postulated palaeolake places the known findings within a completely new palaeoenvironmental context: instead of the previously suspected ford, we assume that the proximity to the Elbe Palaeovalley played a decisive role in the repeated habitation of Lieth Moor. This area, rich in fresh water and fish, along with the dune chain situated to the west, serving as both a vantage point and windbreak, presented an ideal location for awaiting animals migrating along the river Elbe and/or as a resting place within the settlement system of mobile hunter–fisher–gatherer groups.
]]>Geosciences doi: 10.3390/geosciences14020029
Authors: Andrés Cristóbal Xurxo Rigueira Ignacio Pérez-Rey Xian Estévez-Ventosa María Pazo Maria Lia Napoli Brais X. Currás Leandro R. Alejano
The mechanical behavior of block-in-matrix materials is heavily dependent on their block content. This parameter is in most cases obtained through visual analyses of the ground through digital imagery, which provides the areal block proportion (ABP) of the area analyzed. Nowadays, computer vision models have the capability to extract knowledge from the information stored in these images. In this research, we analyze and compare classical feature-detection algorithms with state-of-the-art models for the automatic calculation of the ABP parameter in images from surface and underground outcrops. The outcomes of this analysis result in the development of a framework for ABP calculation based on the Segment Anything Model (SAM), which is capable of performing this task at a human level when compared with the results of 32 experts in the field. Consequently, this model can help reduce human bias in the estimation of mechanical properties of block-in-matrix materials as well as contain underground technical problems due to mischaracterization of rock block quantities and dimensions. The methodology used to obtain the ABP at different outcrops is combined with estimates of the rock matrix properties and other characterization techniques to mechanically characterize the block-in-matrix materials. The combination of all these techniques has been applied to analyze, understand and try, for the first time, to model Roman gold-mining strategies in an archaeological site in NW Spain. This mining method is explained through a 2D finite-element method numerical model.
]]>Geosciences doi: 10.3390/geosciences14020028
Authors: Franziska Glueer Anne-Sophie Mreyen Léna Cauchie Hans-Balder Havenith Paolo Bergamo Miroslav Halló Donat Fäh
While geodetic measurements have long been used to assess landslides, seismic methods are increasingly recognized as valuable tools for providing additional insights into subsurface structures and mechanisms. This work aims to characterize the subsurface structures of the deep-seated gravitational slope deformation (DSGSD) at Heinzenberg through the integration of active and passive seismic measurements. Seismic techniques can hereby deliver additional information on the subsurface structure and mechanisms involved, e.g., the degree of rock mass degradation, the resonant frequencies of the potentially unstable compartments, and the local fracture network orientations that are influenced by wavefield polarization. By employing advanced methods such as H/V analysis, site-to-reference spectral ratios, polarization analysis, surface wave analysis, and the joint multizonal transdimensional Bayesian inversion of velocity structures, we establish a comprehensive baseline model of the landslide at five selected sites. This baseline model shall help identify potential changes after the refilling of Lake Lüsch, which started in 2021. Our results reveal the rupture surface of the DSGSD at various depths ranging from 30 m at the top to over 90 m in the middle of the slope. Additionally, we estimate key parameters including the shear wave velocities of the different rock masses. The 2D geophysical profiles and rock mass properties contribute to the understanding of the subsurface geometry, geomechanical properties, and potential water pathways. This study demonstrates the significance of integrating seismic methods with traditional geodetic measurements and geomorphologic analysis techniques for a comprehensive assessment of landslides, enhancing our ability to monitor and mitigate hazardous events.
]]>Geosciences doi: 10.3390/geosciences14020027
Authors: Cristina Di Salvo Giancarlo Ciotoli Marco Mancini Stefania Nisio Francesco Stigliano
This work aims to describe, classify, and analyze the occurrence of selected natural multi-hazards, specifically pluvial floods and sinkholes, affecting a district in the urban area of Rome, Italy. The procedure is based on a robust geological, geomorphological, and hydrogeological analysis performed using data collected and archived for the scope. The susceptibility is calculated based on geo-hydrological and geomorphological factors, as well as the occurrence of flooding and sinkholes. The areas prone to each single hazard were combined and put into the context of multi-hazard assessment by overlaying the susceptibility with buildings and population data. The resulting map shows that 50% of buildings (6215 inhabitants) are in an area of multi-hazard susceptibility; among these, 25% are in the highest multi-hazard classes (4 and 5). These areas are named “multi-hazard hotspots” because they are affected by many hazards with associated higher impacts. This study demonstrates that a comprehensive approach that combines the examination of geology, hydrogeology, modifications to historical morphology, and the occurrence of geological disasters is effective for mapping geohazards in urban areas and identifying locations with multiple hazards. A multi-hazard hotspot map can be used as a tool for planning actions aimed at reducing the vulnerability and exposure level of the urban population.
]]>Geosciences doi: 10.3390/geosciences14010026
Authors: Majd Ahmad Richard Ray
In geotechnical engineering, dynamic soil models are used to predict soil behavior under different loading conditions. This is crucial for many dynamic geotechnical problems related to earthquakes, train loading and machine foundation design. Researchers agree that under dry or drained conditions, cohesionless soils increase in stiffness with each loading cycle. Soil models that simulate the dynamic behaviors of soils are often coupled with the Masing criteria. Such models neglect the impact of stiffening during cyclic loading, leading to an underestimation in the shear modulus (G). This study investigates the stiffening behavior by conducting laboratory tests on three types of Danube sands using the Resonant Column-Torsional Simple Shear device (RC-TOSS). The increase in the dynamic shear modulus with an increasing number of cycles is substantial, especially for samples with low density. Sometimes, the dynamic shear modulus doubles when loaded at high stress levels for more than 50 cycles. A new model is introduced to simulate the stiffening behavior of dry sand when subjected to cyclic torsional loading. Modifications are proposed for the Ramberg–Osgood and Hardin–Drnevich models and for the Masing criteria to overcome the limitations that accompany these models due to the influence of stiffening caused by repetitive loading being ignored. This model can be implemented in finite element and finite difference software to solve dynamic geotechnical problems.
]]>Geosciences doi: 10.3390/geosciences14010025
Authors: Balázs Bradák Motoharu Okumi
A theory about a young, evolving “stealth ocean” under the ancient-looking surface of Mimas, the moon of Saturn, triggered us to revisit the icy satellite and develop a revised geological map based on Cassini images. The re-mapping of Mimas’s surface aimed to fill the decades-long gap that grew since the publication of the first Voyager image-based pioneering map, and it provided an up-to-date synthetic interpretation of revised and newly discovered features. Despite the map being in its early stage of introduction, it already showed some key features that may play significant roles in the reconstruction of Mimas’s (surface) evolution. The Herschel crater, formed by a global-scale impact, undoubtedly left additional marks, including fault scarps, stair-step faults, and post-impact surface transformation, through mass movements around the crater wall and the peak. Smaller craters left various scars on the surface, including asymmetric craters, whose morphology and allocation we used to reconstruct the regional topographic changes on the surface of Mimas. In addition to the impact-related features, which dominated the surface of the icy satellite, groups of weak, quasi-parallel running linear features, such as undifferentiated lineaments, grooves/through, and ridges, were also observed. The appearance and pattern of those lineaments overlapped with the allocation of various modeled global nonlinear tidal dissipations, supporting the existence of theoretical subsurface stealth oceans.
]]>Geosciences doi: 10.3390/geosciences14010024
Authors: Mohamed M. Awad Ibrahim Eltaleb Mohamed Y. Soliman
Underwater electrical shockwave can be used as a waterless, chemical-free, and environmentally friendly fracturing technique. A detailed experimental study was performed to develop a correlation between the optimum energy required to generate a shockwave that could be used in fracturing rock samples with the wire weight and diameter as independent factors. In addition, the effect of the water volume on the Underwater Electrical Wire Explosion (UEWE) was investigated to quantify the effect of the wellbore fluid volume in the fracturing process. The effect of increasing the discharge energy on the current waveform rising rate, peak amplitude, and fracturing geometry was investigated. A baseline for implementing the shockwave fracturing method on cement and limestone samples was defined to be used in future work. The results show that the water volume has a significant effect on the results of the experiment. A correlation was developed that defined the optimum minimum energy required to burn a certain wire weight with consideration to the wire diameter. Using the optimum required energy or higher will increases the current peak amplitude with the same current waveform rise rate, which leads to higher energy deposition into the wire and prevents the premature breakdown of the wire. The generated shockwave was used to successfully fracture cement and limestone cubic samples.
]]>Geosciences doi: 10.3390/geosciences14010023
Authors: Vyacheslav Zhemchuzhnikov Aitbek Akhmetzhanov Kenzhebek Ibrashev Gauhar Akhmetzhanova
This article examines the geotectonic and sedimentary features of the Upper Devonian–Carboniferous–Permian deposits of the North Caspian basin, represented by deposits of marine Paleozoic-isolated carbonate platforms formed during the subsidence of the basement on the passive continental margin. The top is covered by thick salt-bearing Kungurian deposits from the end of the Early Permian epoch. The formation of carbonate platforms is associated with a major tectonic restructuring of the basin at the turn of the Caledonian and Hercynian eras, when the Paleo-Tethys Ocean was formed and isolated carbonate islands began to grow in an open marine environment. The central part of the depression experienced a long and gradual subsidence that spanned the entire Paleozoic era and the beginning of the Mesozoic era. In the south and east, from the Devonian to the Permian periods, barriers were formed in the form of island carbonate massifs that separated the North Caspian basin from the Paleo-Tethys Ocean. During the formation of the salt-bearing basin, these barriers limited water exchange and ensured a one-way influx of sea water from the open ocean. As a result, at the end of the Permian period, thicker salts accumulated; however, during the collision of the continental massifs, an invasion of many kilometers of redbeds occurred. They initially stopped salt accumulation; however, gradually, in the north of the Caspian Sea during Roadian times, the salt accumulation continued. The post-Roadian time is associated with the influx of large quantities of redbed sediments, which caused gravitational instability in the underlying salt, and salt tectonics began with the formation of domal structures.
]]>Geosciences doi: 10.3390/geosciences14010022
Authors: Luciano Telesca Nino Tsereteli Tamaz Chelidze Vincenzo Lapenna
A spectral analysis of the time dynamics of seismicity occurring in the Enguri area of Georgia from 1978 to 2021 is performed by means of Schuster’s spectrum analysis, periodogram analysis, and empirical mode decomposition. The results of our analysis suggest that earthquakes around the reservoir (within a 50 km radius from the center of the dam) may be due to changes in water level, featured by the yearly cycle of loading and unloading operations of the reservoir. It is observed that the impacts of water fluctuations are more pronounced in shallower strata (down to 10 km) than deeper ones (down to 20 km); this could indicate that earthquakes occurring at deeper levels may primarily result from tectonic forces, whereas those at shallower depths may be predominantly triggered by reservoir-induced factors.
]]>Geosciences doi: 10.3390/geosciences14010021
Authors: Vladimir V. Silantiev Yaroslav M. Gutak Marion Tichomirowa Alexandra Käßner Ruslan V. Kutygin Lyubov G. Porokhovnichenko Eugeny V. Karasev Anastasia S. Felker Aleksandr S. Bakaev Maria A. Naumcheva Milyausha N. Urazaeva Veronika V. Zharinova
The Kuznetsk Basin (Kuzbass) is one of the largest coal basins in Siberia and a reference area for the ancient Angaraland continent. The proximity of the Kuzbass and Siberian Platform caused their biotic similarities in the Late Palaeozoic. However, due to biota endemism, the Kuzbass Upper Palaeozoic does not correlate directly with the International Chronostratigraphic Chart (ICC). This paper discusses radioisotopic (CA-ID-TIMS) dating of zircons from a volcanic tuff located in the Starokuznetsk Formation (Fm). This level matches the interval of the Balakhonka/Kolchugino (B/K) floral change in Kuzbass, i.e., the gradual replacement of cordaitoid-dominated wet forests (Balakhonka flora) with more arid fern–pteridosperm–cordaitoid assemblages (Kolchugino flora). New age (276.9 ± 0.4 Ma) directly correlates the Starokuznetsk Fm with the Upper Kungurian of the ICC. We compared the Kuzbass data with data of the Western Verkhoyanie, where Middle Permian ammonoids (Sverdrupites assemblage) occur in strata recording the B/K floral change. The available (ICC) and new datings indicate the lag between the B/K floral change in low (Kuzbass) and high (Verkhoyanie) latitudes of Angaraland. The B/K floral change in the Kuzbass began in the early Late Kungurian and was completed by the end of this age. In contrast, the B/K floral change in Verkhoyanie began at the end of the Late Kungurian and was completed in the Late Wordian. The delay in the floral changes at different latitudes of Angaraland suggests that existing interregional correlations need further improvement.
]]>Geosciences doi: 10.3390/geosciences14010020
Authors: Mandip Subedi Rajan KC Keshab Sharma Jibendra Misra Apil KC
On 3 November 2023, a moment magnitude (MW) 5.7 (Local Magnitude, ML6.4) earthquake struck the western region of Nepal, one of the most powerful seismic events since 1505 in the region. Even though the earthquake was of moderate magnitude, it caused significant damage to several masonry buildings and caused slope failures in some regions. The field reconnaissance carried out on 6–9 November by the study team, following the earthquake, conducted the first-hand preliminary damage assessment in the three most affected districts—Jajarkot; West Rukum; and Salyan. This study covers the observed typical structural failures and geotechnical case studies from the field study. To have a robust background understanding, this paper examines the seismotectonic setting and regional seismic activity in the region. The observations of earthquake damage suggest that most of the affected buildings were made of stone or brick masonry without seismic consideration, while most of the reinforced concrete (RC) buildings remained intact. Case histories of damaged buildings, the patterns, and the failure mechanisms are discussed briefly in this paper. Significant damage to Khalanga Durbar, a historical monument in Jajarkot, was also observed. Medium- to large-scale landslides and rockfalls were recorded along the highway. The motorable bridge in the Bheri River suffered from broken bolts, rotational movement at the expansion joint, and damage to the stoppers. The damage observations suggest that, despite the existence of building codes, their non-implementation could have contributed to the heavy impact in the region. This study highlights that the local population faces a potential threat of subsequent disasters arising from earthquakes and earthquake-induced landslides. This underscores the necessity for proactive measures in preparedness for future disasters.
]]>Geosciences doi: 10.3390/geosciences14010019
Authors: Kamar Aljundi Ana Vieira José Lapa António Figueiredo Rafaela Cardoso
Shallow Geothermal Energy (SGE) exchanges heat with the ground. In continuous, long-term operation, the initial temperature field can be disturbed, and subsurface thermal changes can be developed. In this paper, the thermal impact of a SGE system under a Mediterranean climate is handled. Temperature monitoring was conducted on 15 investigation boreholes equipped with a total of 92 thermal sensors placed at specific depths. Investigation boreholes were drilled 1–2 m from SGE system borehole heat exchangers installed in a university building. The analysis handles a one-year monitoring period of SGE system operation. Temperature depth profiles, reaching up to 140 m depth, were registered with a 10 min time step, resulting in a large amount of data. Ground thermal conductivity was estimated experimentally and semi-empirically, allowing us to obtain, using a numerical model, the initial undisturbed ground temperature profiles and compare them with the monitored values. Climate data were recorded by the university meteorological station. Globally, the measured and computed data were coherent, and a non-negligible impact of the SGE system operation in the first year was observed. The building orientation as well as the nearby departments had significant impacts on the shallow ground temperature. Maximum ground temperature changes observed at depths higher than 10–20 m, ranging from 2 to 3 °C as observed in different boreholes, indicate that the system is operating efficiently.
]]>Geosciences doi: 10.3390/geosciences14010018
Authors: Luca Maria Puzzilli Valerio Ruscito Sergio Madonna Francesco Gentili Livio Ruggiero Giancarlo Ciotoli Stefania Nisio
The occurrence of sinkhole phenomena in Italy is a prevalent and very uncertain class of geological hazards that pose a significant threat to human infrastructure and individuals. These events are characterized by their unpredictability and the challenges associated with their accurate forecasting. Both natural and anthropic factors influence the occurrence of these events; therefore, accurate identification of the above factors is critical for effective proactive and predictive efforts. The work presented in this paper refers to a collapse that occurred in a volcanic region in northern Latium (central Italy) on 31 January 2023. The area has been monitored using drones since the early stages of the sinkhole’s formation and has continued to date. Then, the collapse and the neighboring area were examined via geophysical and geochemical investigations to identify potential underlying factors. Geophysical and geochemical data were combined to provide a preliminary hypothesis on the collapse’s genesis. The obtained data indicate that the structural collapse can be attributable to the fluctuation in groundwater levels as well as the development of instabilities along its banks, leading to a growth in its dimensions.
]]>Geosciences doi: 10.3390/geosciences14010017
Authors: Marco Rosone Clara Celauro
Scaly clays are structurally complex clay formations found throughout the world. Their typical fissured structure, the low shear strength and the high swelling potential often make them unsuitable for earthworks in road and railway infrastructure. This research has attempted to extend the possibilities of using this geomaterial in this field after appropriate lime treatment. A laboratory test programme was carried out to evaluate the response of the treated geomaterial to typical loads acting on road infrastructures. Unconfined and confined compression tests as well as cyclic triaxial tests, in undrained conditions, were carried out to investigate the static and dynamic mechanical behaviour. The results show that lime treatment induces significant improvements in the geomechanical properties and limits the swelling behaviour upon saturation of the geomaterial. Dynamic tests showed that, after only 28 days of curing, the treated scaly clay became insensitive to the damaging cyclic loading caused by vehicular traffic. The collected results show that the scaly clay can be properly used as a subgrade and embankment layer in road and railway construction with limited economic and environmental costs, after accurate treatment with lime. These results are significant for researchers and practitioners to increase sustainability in the construction of linear infrastructures involving excavations in scaly clays and to avoid landfill, which in some cases represented the only option.
]]>Geosciences doi: 10.3390/geosciences14010016
Authors: Isabel Teixeira Clara Vasconcelos
Studies highlight researchers’ concerns about how science should be taught today. It is recognised that teachers have difficulty involving and motivating students to learn about different complex topics, such as geology. Schools must promote skills development to develop citizens who can be active and informed in society. One way of undertaking this is to use active methodologies such as educational games, in which students play an essential role in developing activities. Games encourage changes in conceptions regarding the relevance of this scientific topic that is often undervalued by students. Games have gained space in recent years in several disciplines, and it is essential that this tool is thought out and planned within a consistent pedagogical proposal. This educational resource is used to increase motivation for learning, as well as enhance and strengthen the effects of learning. An intervention plan can be framed within game-based teaching. Teachers have been underrepresented in the game-based learning literature, with more emphasis on games’ effects. However, the pedagogical issue of games has been particularly relevant in recent decades. The current investigation used a survey given to geology teachers (n = 112) from public and private middle and secondary schools in Portugal. Its purpose was to assess teachers’ perceptions regarding game-based teaching and its potential to promote active learning. Our sample ages ranged from 24 to 64 years (average of 48.9 years old); 81.3% were women and 18.8% were men. The analysis of the results seems to confirm that although they do not always use games to promote learning in geology, most teachers still recognise their potential to motivate, enhance, and reinforce the learning of geological content, with digital games being the preferred option. They emphasise the importance of teacher training in this area and the inclusion of game applications in school textbooks to approach different geology-related themes. Our results seem to indicate some lack of consistency in teachers’ opinions on the impact of games on student learning.
]]>Geosciences doi: 10.3390/geosciences14010015
Authors: Cataldo Godano Nicola Alessandro Pino
Here, we characterize the statistical behaviour of the Mt. Vesuvius seismicity using distinct available catalogues. Our analysis confirms that for this area, the GR distribution exhibited two scaling regimes of the b-value, not commonly observed for the standard frequency-magnitude distribution of earthquakes. By assuming a physical cause, we tested four different hypotheses for the source of the break in the scaling: finite size effect, depth variations in the b-value, radial dependence in the b-value, and different b-values for swarm and non-swarm events. None of the above reasons are able to explain the observation. Thus, we investigated the possibility of some pitfalls in magnitude estimation. Based on our analysis, we suggest there is a bias in the duration magnitude the catalogues are based on. This is due to the arbitrary extrapolation to smaller magnitudes of a linear regression derived for earthquakes with m≥3.0. When a suitable correction is applied to the estimated magnitude, the GR distribution assumes the usual shape, with a b-value closer to that usually observed in volcanic areas. Finally, the analysis of the time variation of some statistical parameters reveals that the state of the volcano appears to be stationary over the entire analysed period, possibly with only a slight decrease in the b-value, indicating a small reduction in differential stress.
]]>Geosciences doi: 10.3390/geosciences14010014
Authors: Kaiyue Luo Alim Samat Jilili Abuduwaili Wenbo Li
As a transboundary river with rich and unique wetland types, the Irtysh River faces various challenges and threats from human activities and climate change, which affect area, type, and function of wetland. To accurately obtain information on the spatial and temporal distribution of wetlands in this basin, this study compares and evaluates the consistency and accuracy of a total of eleven remote sensing (RS) based land use/land cover (LULC), and wetland products. The information extraction effect of each RS product was examined through methods such as wetland area and type description, thematic map comparison, and similarity coefficient and Kappa coefficient calculations, which can reflect the wetland distribution characteristics and differences among the RS products in the Irtysh River Basin. The results show that although there is a consensus among the products in the major wetland distribution areas, there are still obvious deviations in detail depiction due to differences in factors such as data sources and methods. The products of Global 30 m Wetland Fine Classification Data (GWL_FCS30) and Global 30 m Land Cover Data (GLC_FCS30-2020) released by the Institute of Space and Astronautical Information Innovation (ISAI) of the Chinese Academy of Sciences (CAS) have a clear advantage in extracting spatial morphology features of wetlands due to the use of multi-source data, while the Esri Global 10 m Land Cover Data (ESRI_Global-LULC_10m) and products such as the global 10 m land cover data (FROM_GLC10_2017) from Tsinghua University have higher classification consistency. Moreover, data resolution, classification scheme design, and validation methods are key factors affecting the quality of wetland information extraction in the Irtysh River Basin. In practical terms, the findings of this study hold significant implications for informed decision-making in wetland conservation and management within the Irtysh River Basin. By advancing wetland monitoring technologies and addressing critical considerations in information extraction, this research effectively bridges the gap between remote sensing technology and practical applications, offering valuable insights for regional wetland protection efforts.
]]>Geosciences doi: 10.3390/geosciences14010013
Authors: Etsuo Uchida Takumi Yokokura
Research was conducted on plutonic rocks, previously referred to as the Hai Van granitic rocks, distributed in Da Nang and Quang Nam provinces in Central Vietnam. The granitic rocks in Da Nang Province have low magnetic susceptibilities and have geochemical signatures typical of S-type. Additionally, a negative Eu anomaly suggests that the source rock is an organic matter-bearing sedimentary rock. The granitic rocks were likely formed during the collision between the Indochina and South China blocks. In contrast, plutonic rocks in Quang Nam Province have high magnetic susceptibilities and have geochemical signatures of I-type. No Eu anomaly was observed, and they are adakitic rocks in nature. Based on these findings, the plutonic rocks in Quang Nam Province are distinctly different from the Hai Van granitic rocks in Da Nang Province, but they are Van Canh plutonic rocks. The Hai Van granitic rocks in Da Nang Province and the Van Canh plutonic rocks in Quang Nam Province are located in the Truong Son Fold Belt. The Van Canh plutonic rocks are located farther away from the Song Ma Suture Zone than the Hai Van granitic rocks. The Van Canh plutonic rocks were generated due to the subduction of the hot Song Ma Ocean beneath the Indochina Block. The Hai Van granitic rocks are understood to have been generated in a compressional field where the Song Ma Ocean was pushing against the Indochina Block; however, the Van Canh plutonic rocks are supposed to have been generated in an extensional field, like in a back-arc-like environment generated by the subduction of the Song Ma Ocean beneath the Indochina Block.
]]>Geosciences doi: 10.3390/geosciences14010012
Authors: Konstantinos Louvaris Maria Psychogiou Maria V. Triantaphyllou Assimina Antonarakou
This paper presents an initial study of teachers’ perspectives and practices on students’ assessment methods regarding the subject of Geology-Geography taught in junior secondary education in Greece. While the application of descriptive assessment is recorded in other European countries, the main focus of the research is the current situation in Greece, as well as the willingness of science teachers to adopt an alternative form of evaluation and the definition of the respective circumstances. The methodology that was followed in this research included questionnaires that were sent to science teachers. Their answers were processed with the IBM SPSS 23 statistical software. The results reveal that most teaching staff surveyed positively acknowledge the need for an effective appraisal system. Their views and opinions on how student assessment contributes to the overall educational procedure were also recorded during the survey. Statistical analysis of the raw data shows that the views and opinions of teaching staff were not differentiated due to their level of experience or their level of education but only due to their field of specialization. The analysis also points to a range of additional factors that impact teaching staff’s preferences and perceptions of the effectiveness of different student appraisal and evaluation approaches. Such factors create skepticism among teachers towards alternative assessment methods, such as descriptive assessment. While this is preliminary research, it raises important issues regarding effective evaluation methods that would promote students’ development.
]]>Geosciences doi: 10.3390/geosciences14010011
Authors: Nikolaos Gerogiannis Eirini Aravadinou Paraskevas Xypolias
New, detailed geological/structural mapping and field-based structural analysis were carried out to investigate the deformation pattern of well-preserved high-pressure rocks of the Blueschist Unit exposed in SE Syros (Cyclades, Greece). Geological mapping revealed the occurrence of extensive alternations between different rock groups, as well as interfingering patterns in map-scale that are possibly the result of folding. The earlier ductile deformation phase recognized in the mapped area is associated with the development of a penetrative foliation, which was formed at eclogite/blueschist-facies conditions under peak metamorphism. The subsequent main deformation phase occurred under blueschist facies conditions synchronous with the early stages of exhumation of the high-pressure rocks. This phase is mainly associated with the formation of WNW-trending folds and a pervasive axial planar foliation linked with ESE-directed shearing. The main deformation ceased under blueschist-facies conditions, and exhumation of the rocks to greenschist-facies conditions took place under very weak and localized deformation. Greenschist retrogression observed in the southwestern part of the mapped area seems to be controlled by fluids, rather than by intense deformation and formation of major syn-greenschist shear zones.
]]>Geosciences doi: 10.3390/geosciences14010010
Authors: Adamantios Kilias
In this paper, the Hellenic orogenic belt’s main geological structure and architecture of deformation are presented in an attempt to achive a better interpretation of its geotectonic evolution during Alpine orogeny. This study was based not only on recent research that I and my collaborators conducted on the deformational history of the Hellenides but also on more modern views published by other colleagues concerning the Alpine geotectonic reconstruction of the Hellenides. The structural evolution started during the Permo–Triassic time with the continental breaking of the supercontinent Pangea and the birth of the Neotethyan ocean realm. Bimodal magmatism and A-type granitoid intrusions accompanied the initial stages of continental rifting, followed by Triassic–Jurassic multiphase shallow- and deep-water sediment deposition on both formed continental margins. These margins were the Apulian margin, containing Pelagonia in the western part of the Neotethyan Ocean, and the European margin, containing continental parts of the Serbo-Macedonian and Rhodope massifs in the eastern part of the Neotethyan ocean. Deformation and metamorphism are recorded in six main deformational stages from the Early–Middle Jurassic to the present day, beginning with Early–Middle Jurassic Neotethyan intra-oceanic subduction and ensimatic island arc magmatism, as well as the formation of a suprasubduction oceanic lithosphere. Compression, nappe stacking, calc-alkaline magmatism, and high-pressure metamorphic events related to subduction processes alternated successively over time with extension, orogenic collapse, medium- to high-temperature metamorphism, adakitic and calc-alkaline magmatism, and partial migmatization related to the uplift and exhumation of deep crustal levels as tectonic windows or metamorphic core complexes. A S- to SW-ward migration of dynamic peer compression vs. extension is recognized during the Tertiary Alpine orogenic stages in the Hellenides. It is suggested that all ophiolite belts in the Hellenides originated from a single source, and this was the Neotethyan Meliata/Maliac-Axios/Vardar ocean basin, parts of which obducted during the Mid–Late Jurassic on both continental margins, Apulian (containing Pelagonia) and European (containing units of the Serbo-Macedonian/Rhodope nappe stack), W-SW-ward and E-NE-ward, respectively. In this case, the ophiolite nappes should be considered far-traveled nappes on the continental parts of the Hellenides associated with the deposition of Middle–Late Jurassic ophiolitic mélanges in basins at the front of the adjacent ophiolite thrust sheets. The upper limit of the ophiolite emplacement are the Mid–Upper Jurassic time(Callovian–Oxfordian), as shown by the deposition of the Kimmeridgian–Tithonian Upper Jurassic sedimentary carbonate series on the top of the obducted ophiolite nappes. The lowermost Rhodope Pangaion unit is regarded as a continuation of the marginal part of the Apulian Plate (External Hellenides) which was underthrust during the Paleocene–Eocene time below the unified Sidironero–Kerdylia unit and the Pelagonian nappe, following the Paleocene–Eocene subduction and closure of a small ocean basin in the west of Pelagonia (the Pindos–Cyclades ocean basin). It preceded the Late Cretaceous subduction of the Axios/Vardar ocean remnants below the European continental margin and the final closure of the Axios/Vardar ocean during the Paleocene–Eocene time, which was associated with the overthrusting of the European origins Vertiskos–Kimi nappe on the Sidironero–Kerdylia nappe and, subsequently, the final collision of the European margin and the Pelagonian fragment. Subsequently, during a synorogenic Oligocene–Miocene extension associated with compression and new subduction processes at the more external orogenic parts, the Olympos–Ossa widow and the Cyclades, together with the lower-most Rhodope Pangaion unit, were exhumed as metamorphic core complexes.
]]>Geosciences doi: 10.3390/geosciences14010009
Authors: Dmitry Zozulya Lyudmila N. Morozova Kåre Kullerud Ayya Bazai
In this paper we present textural and compositional data for columbite group minerals (CGMs) and associated Nb-Ta-Sn oxides from lithium-beryllium-tantalum pegmatite deposits of the Kolmozero–Voronja belt, NW Russia, with the aim of deciphering these characteristics for minerals from deposits with different mineral signatures and lithium ore grade. Minerals from four deposits, including two of world-class (Kolmozero and Polmostundra), are examined. The main controlling factors for CGM compositional ranges are the diversity and rate of magmatic fractionation, hydrothermal overprint and mineral paragenesis, following the specific geochemical signature of the different pegmatite deposits. CGM from Kolmozero include several mineral species (columbite-(Fe), columbite-(Mn), tantalite-(Fe), and tantalite-(Mn)), showing large compositional variations, mainly controlled by Nb-Ta fractionation (Ta/(Ta + Nb) = 0.16–0.70; Mn/(Mn + Fe) = 0.45–0.63). Textural patterns are various (oscillatory, homogeneous, and patchy); spongy domains and overgrowing Ta-rich rims are also observed somewhere. This indicates the involvement of numerous magmatic and hydrothermal processes. The Polmostundra CGMs are represented by columbite-(Fe) with Ta/(Ta + Nb), ranging from 0.05 to 0.39; some crystals are homogenous, and others present normal, oscillatory, mottled and reverse-zoning patterns. The Okhmylk CGMs are irregular normal, patchy and homogeneous columbite-(Fe) and columbite-(Mn), with Ta/(Ta + Nb) = 0.09–0.24 and Mn/(Mn + Fe) = 0.29–0.92, indicating the suppressed magmatic fractionation and iron drop due to precipitation of Fe minerals. Columbite-(Fe) and columbite-(Mn) from the Be-Ta Shongui deposit are less evolved, with Ta/(Ta + Nb) = 0.07–0.23 and Mn/(Mn + Fe) = 0.31–0.55. The minerals are characterized by progressive normal, oscillatory, homogeneous and irregular reverse patterns. Associated pyrochlore minerals occur both as early magmatic (Kolmozero) and late hydrothermal (Polmostundra, Okhmylk). Cassiterite is found only in the Okhmylk dykes, and is apparently of hydrothermal origin. CGM from Li pegmatites have impurities of Ti (0.01–0.05 apfu) and W (up to 0.02 apfu), whereas CGM from Be pegmatites contains elevated Ti (up to 0.09 apfu). The mineral system analysis presented here is relevant for exploration.
]]>Geosciences doi: 10.3390/geosciences14010008
Authors: Mauro Palo Francesco Scotto di Uccio Matteo Picozzi Gaetano Festa
A pilot study employing a template-matching approach on the detection of repeating earthquakes (or repeaters) in a small volume of the Irpinia fault (Southern Italy) is presented here. A catalog of repeaters nucleating over about a decade with local magnitudes ranging between ML 0.4 and ML 1.7 is generated. The events nucleate at depths of about 11 km over a fault patch with a size of about 600 m. Assuming a constant stress drop for all repeaters, the yearly coseismic slip rate of the patch is estimated in the range of 1–4.8 mm with a mean value of about 3.4 mm, which is close to the fault slip rate estimated by geodetic approaches. Given the mechanical properties of the medium in the source region of the repeaters revealed by previous tomographic studies, and in particular the high Vp/Vs ratio (close to 1.95), it is postulated that these events are fluid triggered, consistently with the mechanism proposed for the generation of most of the microseismicity in the area. The encouraging outcomes of this study suggest to focus future measurement campaigns on this area and open perspectives to extend this approach to other segments of the Irpinia fault to reveal small-scale frictional properties in an area capable to generate M7 earthquakes.
]]>Geosciences doi: 10.3390/geosciences14010007
Authors: Ekaterina V. Levashova Sergey G. Skublov Dmitry A. Zamyatin Qiuli Li Dmitry S. Levashov Xianhua Li
The zircon from the pegmatite of the Adui granitic massif displays the unique the rare earth element (REE) distribution spectrum with the tetrad effect in REE fractionation. The tetrad effect often occurs in granitoid rocks, but it is rarely encountered in minerals, e.g., zircon. Fluid saturated with volatiles, water and trace elements is a factor responsible for the tetrad effect in the zircon. The detailed isotopic-geochemical study of the zircon has revealed several zones differing in internal structure (in the back-scattered electron (BSE) image), composition and REE distribution. The zones indicate changes in the crystallization environment provoked by the evolution of the pegmatite-forming melt. They occur as the gradually growing changes in composition from the unaltered zones that are light-colored in BSE to the altered zones that are dark-colored in BSE. The unaltered zones are consistent in composition and geochemical features with magmatic zircons. The high content of trace (U, Th, REE) and volatile elements (F, Cl) in water suggests its crystallization from the fluid-saturated magmatic melt. The altered zircon zones occur as recrystallized zones with high content of non-formula elements (Y, Ca, Sr, Nb, P), a non-differentiated REE distribution spectrum and an absent Ce anomaly. These features are consistent with those of hydrothermal-metasomatic zircon.
]]>Geosciences doi: 10.3390/geosciences14010006
Authors: Olga Bjelotomić Oršulić Matej Varga Sefa Yalvac
A destructive Mw = 6.2 earthquake struck NW Croatia on 29 December 2020, ranking among the most hazardous events in the country in the last century. This study assesses the impact of the earthquake on the permanent geodetic stations of the Croatian national positioning system. Using a novel approach, we combined positioning station data with satellite radar data for the first time in a geodynamic study across Croatia. The analysis involved collecting daily solutions data from 11 nearby network stations as well as multi-temporal satellite images before and after the earthquake. The results reveal a significant co-seismic shift, with the Sisak reference station experiencing the largest displacement of 5 cm to the southeast. Stations up to 100 km from the epicenter exhibited horizontal shifts between 1 and 2.5 cm and vertical shifts between 2 and 4 cm. Satellite images confirmed the co-seismic effects on the permanent stations. The study establishes a strong correlation between geodetic and geological findings, suggesting that vertical displacements result from superficial deposit consolidation in the river plains due to the earthquake shaking, while positional displacement reflects tectonic block movements along the activated strike-slip fault system. The late 2020 earthquake may have further relaxed the accumulated strain on the Mt. Medvednica thrust fault system, which had ruptured in early 2020 with a lower magnitude than expected.
]]>Geosciences doi: 10.3390/geosciences14010005
Authors: Osman Orhan Mahmud Haghshenas Haghighi Vahdettin Demir Ergin Gökkaya Francisco Gutiérrez Djamil Al-Halbouni
The endorheic Konya Basin is a vast aggradational plain in Central Anatolia, Türkiye. It occupies a significant portion of Konya Province, covering approximately 50,000 km2. The basin is subjected to intense groundwater withdrawal and extensive agricultural activities with excessive irrigation. These activities have led to human-induced hazards, such as sinkholes and regional land subsidence. Although sinkhole occurrence mainly occurs in the Karapınar area, land subsidence is primarily observed in the central sector of Konya city, with 2 million inhabitants, as well as in various parts of the basin. This study focuses on determining the extent and rate of land subsidence throughout the basin, understanding sinkhole formation, and unraveling their relationship with anthropogenic activities. For this purpose, Interferometric Synthetic Aperture Radar (InSAR) analysis of Sentinel-1 data from 2014 to 2022 was conducted to identify and assess land subsidence. We also used the land cover data and groundwater-level information to better understand the spatial and temporal patterns of land subsidence and sinkhole occurrence. Additionally, the land cover data were used to resolve spatial–temporal variations in the cultivated area and urbanization, which are the main factors governing groundwater exploitation in the region. Our study identified widespread subsidence zones with rates as high as 90 mm/y. Groundwater overexploitation to sustain extensive agricultural operations is the main cause of the high rate of land subsidence. Additionally, it was discovered that the number of sinkholes has substantially increased due to anthropogenic influences, currently amounting to as many as 660.
]]>Geosciences doi: 10.3390/geosciences14010004
Authors: Julianna Martin Jeff B. Langman
Restoration of open-pit mines may utilize waste rock for landscape reconstruction, which can include the construction of backfill aquifers. Weathering and contaminant transport may be different in backfill aquifers compared to the surrounding aquifer because of newly available mineral surfaces and transportable nano- to micro-scale particles generated during mining. Waste rock from the Cordero Rojo open-pit coal mine in the Powder River Basin was exposed to benchtop leachate experiments for 20 weeks at temperatures of 5 °C and 20 °C. Collected leachate was analyzed for Eh, pH, specific conductance, alkalinity, and cation and anion concentrations as unfiltered and 0.45-μm and 0.2-μm filtered concentrations. During the experiment, leachate Eh and pH substantially varied during the first 55 days, which corresponds to a period of high specific conductance (>1000 µS/cm) and alkalinity (>200 mg/L). Correspondingly, anion and cation concentrations were the largest during this early weathering stage, and the filter fractions indicated multiple forms of transported elements. After this early weathering stage, column leachate evolved towards a weathering equilibrium of neutral, oxidizing, and low solute conditions indicated by positive Eh values, pH near 7, and specific conductance <500 μS/cm. This evolution was reflected in the decline and stabilization or non-detection of metal(loid) concentrations reflective of a shift to primarily bulk aluminosilicate weathering when coal- and salt-associated elements, such as arsenic, cadmium, and selenium, were not detected or at minimal concentrations. Over the course of the experiment, the solute trend of certain elements indicated particular weathering processes—cadmium and nanoparticle transport, selenium and salt dissolution, and arsenic and pyrite oxidation. The mining of overburden formations and use of the waste rock for backfill aquifers as part of landscape reconstruction will create newly available mineral surfaces and nanoparticles that will weather to produce solute concentrations not typically found in groundwater associated with the original overburden.
]]>Geosciences doi: 10.3390/geosciences14010003
Authors: Sisay S. Mekonen Scott E. Boyce Abdella K. Mohammed Markus Disse
Groundwater resource management requires understanding the groundwater basin’s hydrogeology and would be improved with the development of a three-dimensional hydrogeologic framework model (HFM). A wide range of methods and software exist to quantify the extent, structure, and properties of geologic systems. However, most geologic software is proprietary and cost-prohibitive for use in developing countries. GemPy is a Python-based, open-source (no-cost) tool for generating three-dimensional geological models. This study uses available data and GemPy to develop the Kobo Valley Hydrogeologic Framework Model (KV-HFM), a three-dimensional HFM for Kobo Valley in northern Ethiopia, which is part of the East African Rift System. The KV-HFM is a conceptual model that comprises the hydrostratigraphy, structural features, and hydraulic properties of the Kobo Valley groundwater system. The limited data described the extent and altitude of the hydrostratigraphic units using the GemPy implicit potential–field interpolation. The KV-HFM showed the existence of an east-to-west, structural-based groundwater divide composed of volcanic rock and clay. This divide splits the catchment into two groundwater systems with limited interconnected flow. This study illustrates the use of open-source software for developing an HFM using sparse, existing geologic data.
]]>Geosciences doi: 10.3390/geosciences14010002
Authors: Elisavet-Isavela Koutsoupaki Dimitris Sotiriadis Nikolaos Klimis Ioannis Dokas
Fragility curves of retaining walls constitute an efficient tool for the estimation of seismic risk and can be utilized for prevention from potential damage or for immediate decision-making. In this work, fragility curves for cantilever retaining walls of three different heights are proposed, considering cohesionless soil materials. The seismic response of the soil-wall system, in terms of permanent vertical ground displacement of the backfill soil and permanent horizontal displacement of the wall’s base, is estimated by conducting non-linear time history analyses, through the 2D finite element simulation method. Five initial conditions are investigated regarding the value of the global factor of safety (FS) under static conditions. An initial value of FS equal to 1.5 is considered for dry conditions. If the presence of the water table is taken into account, the corresponding FS drops to values ranging from 1.4 to 1.1. Parameters that characterize seismic intensity are evaluated based on criteria, in order to identify the intensity measures that best correlate with the system’s response. Three damage states are adopted, corresponding to minor, moderate, and extensive damage. The approach of combined damage criteria is also investigated. Finally, fragility curves are derived demonstrating the degree of dependency on initial conditions.
]]>Geosciences doi: 10.3390/geosciences14010001
Authors: Vladimir Kutcherov Olga Sivalneva Alexandr Buzilov Alexandr Postnikov
The ring structure of Siljan, located in the central part of Sweden, is considered by many researchers to be a meteorite (impact) crater. Impact craters are among the most complex geological objects on the Earth. The origin and formation of these structures still raises many questions. To find answers to these questions we need reliable geological information about the structure of the crater and the composition of the rocks. Information about the thickness and geological structure of the Siljan Ring area sedimentary cover will help to understand the process of the Siljan Ring structure’s formation as well as other similar geological formations on the Earth. Here, we present the results of laboratory studies of sedimentary rock samples taken from four exploration wells drilled in the vicinity of the Siljan Ring crater, which made it possible to compile their detailed lithological description. The laboratory studies included a structural analysis of the samples, and a texture and mineralogical analysis in thin sections. A structure analysis was carried out visually, while structural and mineralogical analyses were carried out on thin sections using a polarizing microscope and a scanning electron microscope. The main components of the rocks (minerals and fragments), along with their ratio and secondary transformations, were determined. The results of the structural analysis of the samples, and the textural and mineralogical analysis of the rocks in thin sections, showed that the sediments’ composition in the sedimentary cover near the Siljan Ring structure changes in different areas in accordance with their facies and stratigraphic characteristics. Furthermore, a change in the thickness of the sections and the succession sequences of rock units was established. A change of this nature is presumably caused by tectonic disturbances of an endogenous or impact source.
]]>Geosciences doi: 10.3390/geosciences13120389
Authors: Lucien F. Montaggioni Bernard Salvat Edwige Pons-Branchu Bertrand Martin-Garin Arnaud Dapoigny Éric Brunaud Gilbert Poli Miri Tatarata
Assumptions about the fate of low-lying coral reef islands (atolls) facing global warming are poorly constrained, due to insufficient information on their depositional history. Based on the U/Th dating of 48 coral clasts, the chronostratigraphic analysis of excavated sections through rim islets (motu) at the windward and leeward sides of Fakarava Atoll (Tuamotu, French Polynesia) reveal that the deposition of coral detritus started approximately 2000 years ago. Most of these deposits lie on conglomerate pavements or reef flat surfaces, and are about 4500 to 3000 years old. The islet expansion at the windward sites seems to have operated coevally across the reef rim, from the ocean-facing shore lagoonwards. Meanwhile, well-developed, continuous, elongated, vegetated islets mostly occur along the windward, northeast to southeast coast, and isolated islets, vegetated or not, associated with the dense networks of conglomerates, are common on the leeward, partly submerged, western rim. Islet accretion on the windward rim sides is believed to have been mainly triggered by winter storms and occasional cyclonic events, whilst the leeward atoll parts were most likely shaped by distant-source swells from mid to high latitudes. The projections of the accelerated sea level rise in the future suggest that the long-term islet stability at Fakarava could be altered because the islets have accreted under the conditions of the falling sea level.
]]>Geosciences doi: 10.3390/geosciences13120388
Authors: Ilsa Rosianna Eka Djatnika Nugraha Hirofumi Tazoe Heri Syaeful Adi Gunawan Muhammad I Gde Sukadana Frederikus Dian Indrastomo Ngadenin Fadiah Pratiwi Agus Sumaryanto Sucipta Hendra Adhi Pratama Deni Mustika Leli Nirwani Nurokhim Yasutaka Omori Masahiro Hosoda Naofumi Akata Shinji Tokonami
Mamuju is an area of high natural radiation in Indonesia with high natural radiation levels (average 613 nSv h−1). Mamuju is anomalous due to its high average 238U and 232Th concentrations of 22,882 and 33,549 Bq kg−1, respectively, in laterite and rock. High natural radionuclide concentrations of 238U, 232Th, and 40K have also been reported in soil samples from several locations in Mamuju, including Botteng, Northern Botteng, Takandeang, Ahu, and Taan. High radiation levels are related to radioactive mineral occurrences in the Adang volcanic complex, comprised of phonolitoid and foiditoid lithologies. According to the International Atomic Energy Agency (IAEA), uranium deposits can be classified into several types, among them a volcanic-related deposits, which include three sub-types: stratabound, structure-bound, and volcano-sedimentary deposits. This study aims to characterize volcanic rock deposit sub-types in the Mamuju area based on uranium radioisotope measurements. The uranium isotopes were measured using a tandem quadrupole inductively coupled plasma mass spectrometer combined with chemical separation by extraction chromatography using UTEVA resin. The analytical results for the 234U/238U ratios are used to determine the formation characteristics of minerals in each deposit sub-type based on mineral formation age, post-formation processes, and disturbances that affected the formation processes. Based on geochronological calculations using 234U/238U mineralization age, the deposits in the Mamuju area are 0.914–1.11 million years old and are classified as recent mineralization. These data have important implications for tracing uranium source rocks in the Mamuju area and may explain the anomalously high radiation levels in the Mamuju area.
]]>Geosciences doi: 10.3390/geosciences13120387
Authors: Dimitrios Nikolopoulos Ermioni Petraki Muhammad Rafique Aftab Alam Demetrios Cantzos Panayiotis Yannakopoulos
This paper reports kHz EM observations recorded by the Kardamas station in Ilia, Greece a few days before four near-field earthquakes occurred within a 24 km radius, with epicentral depths below 29 km. This work investigated the fractal features hidden in the EM observations via power-law analysis. All EM signals exhibited characteristic fractal epochs with organisation in space and time. A significant number of accurate fractal segments were delineated in the majority of the EM observations. A significant number of fractal areas corresponded to predictable Class I fBm category with 1 ≤ b ≤ 3 (0 ≤ H ≤ 1). Numerous persistent key-periods are reported with 2 < b ≤ 3 (0.5 ≤ H ≤ 1) which are deemed as signs of impeding earthquakes according to the literature. Numerous segments were found with strong persistent b-values in the range (2.3 ≤ b ≤ 3) (0.65 ≤ H ≤ 1) and b-values corresponding to switching between antipersistency and persistency with (1.7 ≤ b < 2.3) (0.35 ≤ H < 0.65). These are deemed as the most significant precursory signs. Interpretations are given via the asperity model.
]]>Geosciences doi: 10.3390/geosciences13120386
Authors: Lorenzo Milan Maria Lia Napoli Monica Barbero Marta Castelli
In this research article, we propose a practical methodology for evaluating the affecting potential of detachment areas in rockfalls. Our innovative approach combines an assessment of the visibility of rockfall source areas, with reference to specific rockfall scenarios and elements at risk, considering the rockfall Susceptibility Index to Failure (SIF) of these areas. The result is the characterization of source areas through a rockfall Source Affecting Index (SAI), which considers both the morphology of the slope and the geostructural conditions of the rock walls. This information can be very useful since it aids in optimizing more in-depth analyses, as well as the placement of monitoring instruments or stabilization systems. The proposed methodology has been implemented in the open-source software QGIS through the development of an easy-to-use plugin named Ranking of the Affecting Potential of Detachment Areas in Rockfalls, or “RADAR”. RADAR is designed to be used in conjunction with QPROTO, a well-known QGIS plugin for preliminary rockfall susceptibility/hazard analyses based on a visibility analysis and a simplified mechanical method. To demonstrate the effectiveness of the proposed approach, an application to a case study located in the Western Alps (Bardonecchia, Italy) is presented and discussed in the paper.
]]>Geosciences doi: 10.3390/geosciences13120385
Authors: Jaime Cuevas-González Davinia Díez-Canseco Javier Elez Carlos Pérez-Mejías Hai Cheng Juan Carlos Cañaveras
The search for a continuous continental record of interglacial periods in semi-arid regions is problematic due to the absence of stable and continuous sedimentary systems over time in this type of climate. In this work, a relatively stable basin is described and analyzed during the last interglacial period in a semi-arid region of the western Mediterranean. For this purpose, a geomorphological, stratigraphic and sedimentological study has been carried out, with dating through 230Th. A semi-endorheic Pleistocene section has been identified, with two units that correspond to a fluvial-lacustrine system (unit P1) and an alluvial system (unit P2). Unit P1 has been dated to the MIS 5e interglacial episode. A framework for future studies is described, in which the Aljezares Pleistocene basin can be considered as a possible source of paleoenvironmental and paleoclimatic information in semi-arid regions from the last interglacial period.
]]>Geosciences doi: 10.3390/geosciences13120384
Authors: Felix Schmid Jorge Leandro
As climate change increases the occurrences of extreme weather events, like flooding threaten humans more often. Hydrodynamic models provide spatially distributed water depths as inundation maps, which are essential for flood protection. Such models are not computationally efficient enough to deliver results before or during an event. To ensure real-time prediction, we developed a feature-informed data-driven forecast system (FFS), which interpreted the forecasting process as an image-to-image translation, to predict the maximum water depth for a fluvial flood event. The FFS combines a convolutional neural network (CNN) and feature-informed dense layers to allow the integration of the distance to the river of each cell to be predicted into the FFS. The aim is to ensure training for the whole study area on a standard computer. A hybrid database with pre-simulated scenarios is used to train, validate, and test the FFS. The FFS delivers predictions within seconds making a real-time application possible. The quality of prediction compared with the results of the pre-simulated physically-based model shows an average root mean square error (RMSE) of 0.052 for thirty-five test events, and of 0.074 and 0.141 for two observed events. Thus, the FFS provides an efficient alternative to hydrodynamic models for flood forecasting.
]]>Geosciences doi: 10.3390/geosciences13120383
Authors: Artur Boháč Emil Drápela
Bohemian Switzerland is a national park in Northern Czechia famous for its sandstone rocks, which were affected by a massive fire in 2022. Specific geomorphology of the region affected the spreading of the fire and complicated its extinguishing. The fire directly or indirectly damaged several geosites in Bohemian Switzerland. The catastrophe brought a possibility of showing the unique connection between geoheritage and present climate change and increasing awareness about the problems. The text is focused on field education of geography, striving to strengthen environmental awareness among students through educating their teachers. The research is based on desk research, field observation and didactic principles application. The causes of the fire were complex, including physical geographical (drought and bark beetle calamity within climate change) and human geographical phenomena (mass tourism and tourist misbehavior, inappropriate forestry practices). The teachers we worked with reached similar conclusions at the end of our course. Our fieldwork educational concept proved viable and was appreciated by them mainly thanks to the incorporation of research-based learning and the absence of unnatural emphasis on climate change. Climate change is a politicized topic, bringing controversies to the classrooms in the peripheral region. The approach we proposed is anchored in inquiry-based methods and touches on the issue indirectly.
]]>Geosciences doi: 10.3390/geosciences13120382
Authors: Abdellah Khouz Jorge Trindade Pedro Pinto Santos Sérgio C. Oliveira Fatima El Bchari Blaid Bougadir Ricardo A. C. Garcia Eusébio Reis Mourad Jadoud Tarik Saouabe Said Rachidi
Floods are natural disasters that often impact communities living in low-lying areas in the northern and central parts of Morocco. In this study, our aim was to create a flood susceptibility map using three methods; the hierarchy process (AHP) frequency ratio model (FR) and the weights of evidence (WoE) model. We extensively examined the area identified by these approaches using a hydraulic analysis software called HEC-RAS (version 6.3.1). Our analysis focused on the Essaouira watersheds in Morocco, where we identified around 197 flood locations. Out of these, we randomly selected 70% for modeling purposes while the remaining 30% were used for validation. Ten factors that influence floods were considered, such as slope, elevation, proximity to rivers, drainage density, stream order, land use patterns, rainfall data, lithology (permeability level) index (TWI), and curvature. We obtained these factors from data sources. Finally, we generated a flood susceptibility map and evaluated its accuracy by calculating the area under the curve (AUC). The validation results confirmed that all three models were robust and effective with an AUC of 90. Moreover, the research uncovered a trend of vulnerability with the most susceptible area being in close proximity to the city of Essaouira along the Oued Ksob. A detailed analysis using HEC-RAS was conducted at this identified location, pinpointing the village of Diabat as highly exposed. These findings hold significance for flood management, empowering decision makers, scholars, and urban planners to make informed choices and implement strategies that can minimize the impact of floods in susceptible regions while minimizing potential damages.
]]>Geosciences doi: 10.3390/geosciences13120381
Authors: Russell Rogers Markus Pracht
In a pilot study, hyperspectral image analysis was applied to four boreholes from the North Midlands Block in Ireland. The selected holes are extremely well characterised lithologically and have a detailed micropalaeontology accurately constraining stratigraphic positions. Hyperspectral facies were defined using features extracted from the hyperspectral data and compared with existing litho- and biostratigraphic logs and samples. These were able to distinguish changes in the lithologies of the cores and were useful for defining unbiased lithological contacts and for regional correlations.
]]>Geosciences doi: 10.3390/geosciences13120380
Authors: Mourani Sinha Mrinmoyee Bhattacharya M. Seemanth Suchandra A. Bhowmick
Probabilistic models for long-term estimations and deep learning models for short-term predictions have been evaluated and analyzed for ocean wave parameters. Estimation of design and operational wave parameters for long-term return periods is essential for various coastal and ocean engineering applications. Three probability distributions, namely generalized extreme value distribution (EV), generalized Pareto distribution (PD), and Weibull distribution (WD), have been considered in this work. The design wave parameter considered is the maximal wave height for a specified return period, and the operational wave parameters are the mean maximal wave height and the highest occurring maximal wave height. For precise location-based estimation, wave heights are considered from a nested wave model, which has been configured to have a 10 km spatial resolution. As per availability, buoy-observed data are utilized for validation purposes at the Agatti, Digha, Gopalpur, and Ratnagiri stations along the Indian coasts. At the stations mentioned above, the long short-term memory (LSTM)-based deep learning model is applied to provide short-term predictions with higher accuracy. The probabilistic approach for long-term estimation and the deep learning model for short-term prediction can be used in combination to forecast wave statistics along the coasts, reducing hazards.
]]>Geosciences doi: 10.3390/geosciences13120379
Authors: Vincenzo Guerriero
This technical note illustrates a linear regression algorithm based on the Maximum Likelihood Estimation (MLE), with a related Excel spreadsheet and VBA program, adapted to the case of fracture aperture data sets in which sampling of the smallest values is problematic. The method has been tested by means of Monte Carlo simulations and exhibits significantly better convergence against Least Squares criterion (LSM). As the method is conceptually simple and, following the indications illustrated here, the relative spreadsheet can be easily designed, it may be routinely used, instead of the Least Squares, in fracture analysis. Furthermore, the proposed method, with the appropriate modifications, might be potentially extended to other cases in geology and geophysics, in which significant biases at the lower limits of the sampling scale occur.
]]>Geosciences doi: 10.3390/geosciences13120378
Authors: Mohammad Wasif Naqvi Diwakar Kc Liangbo Hu
Debris flows characterized by their rapid velocity and composition of water, mud, soil, and boulders, have the potential to inflict significant harm and present hazards to human life, infrastructure, and the natural surroundings. Numerical simulations provide a cost-effective approach for investigating different scenarios, hence boosting comprehension of flow dynamics and interactions. However, accurate modelling of these flows typically face difficult challenges arising from inherent modeling constraints and insufficient historical event data. The primary objective of the present study is to conduct numerical modeling and sensitivity analysis of the debris flow event that occurred in the Pitztal Valley, Austria in August of 2009, based on a multi-phase model for debris flows. The validation of the simulation results involves the comparison with the observed deposition patterns in the field. Various validation factors are employed to evaluate the accuracy of the simulated deposit and demonstrate a satisfactory level of precision in predicting deposition patterns. A sensitivity analysis is also conducted to examine the influence of in situ conditions on the effects of debris flow. The results demonstrate that numerical modelling can play an important role in engineering hazard assessment by analyzing the existing model’s effectiveness in simulating both historical and projected debris flow events.
]]>Geosciences doi: 10.3390/geosciences13120377
Authors: Igor S. Peretyazhko Elena A. Savina
Melted rocks (clinkers and paralavas) of the Mongolian combustion metamorphic (CM) complexes were formed during modern and ancient (since the Quaternary) wild-fires of brown coal layers in the sedimentary strata of the Early Cretaceous Dzunbain Formation. According to XRD, Raman spectroscopy, and SEM-EDS data, cordierite, sekaninaite, indialite, ferroindialite, silica polymorphs, mullite, Fe-mullite, anhydrous Al-Fe-Mg silicate spinel (presumably new mineral), and other phases were identified. It has been established that isomorphic impurity of potassium in the cordierite-group minerals does not correlate with their crystal structure (hexagonal or orthorhombic). Indialite and ferroindialite retained their hexagonal structure in some fragments of the CM rocks, possibly due to the very fast cooling of local zones of sedimentary strata and the quenching of high-temperature K-rich peraluminous melt. Clinkers, tridymite–sekaninaite, and cristobalite–fayalite ferroan paralavas were produced by partial melting of Fe-enriched pelitic rocks (mudstone, siltstone, and silty sandstone) in a wide temperature range. The formation of mullite, Fe-mullite, and Al-Fe-Mg silicate spinel in clinkers developed from dehydration–dehydroxylation and incongruent partial melting of Fe-enriched pelitic matter (Al-Mg-Fe-rich phyllosilicates, ‘meta-kaolinite’, and ‘meta-illite’). Large-scale crystallization of these minerals in the K-rich peraluminous melts occurred, presumably, in the range of T > 850–900 °C. The subsurface combustion of coal layers heated the overburden pelitic rocks from sedimentary strata to T > 1050 °C (judging by the formation of cordierite-group minerals) or locally till the melting point of detrital quartz grains at T > 1300 °C and, possibly, till the stability field of stable β-cristobalite at T > 1470 °C. Ferroan paralavas were formed during the rapid crystallization of Fe-rich silicate melts under various redox conditions. From the analysis of the liquidus surface in the Al2O3–FeO–Fe2O3–SiO2 major-oxide system, it follows that the least high-temperature (<1250 °C) and the most oxidizing conditions occurred during the crystallization of mineral assemblages in the most-enriched iron silicate melts parental for cristobalite–fayalite paralava.
]]>Geosciences doi: 10.3390/geosciences13120376
Authors: Mohammad Hakim Rezayee Ahamd Qasim Akbar Torabaz Poyesh Ezatullah Rawnaq Khair Mohammad Samim Hideki Mizunaga
The Panjshir Fe-Polymetallic ore deposit is a valuable geological resource in Afghanistan, rich in iron and multiple essential metallic minerals, with substantial potential for industrial development. The exploration phase faces challenges related to the complex geological settings, high variability of mineral compositions, and the need for advanced geophysical techniques to accurately locate and assess valuable metallic resources. Considering the strong magnetic characteristics exhibited by Fe-Polymetallic elements, geomagnetic data were employed to analyze and map the likely prospectivity of Fe-Polymetallic deposits within the study area. Multi-scale edge detection techniques were employed to accurately map the boundaries of magnetic bodies by utilizing the upward continued analytical signal amplitude. The presence of a fault system on the geological map confirmed the structural information derived from our edge detection techniques. Advanced magnetic data inversion techniques were employed to create a three-dimensional representation of the distribution of magnetic bodies linked to Fe-Polymetallic deposits. In our efforts to reduce the impact of remnant magnetization in the study area, we adopted a comprehensive strategy by employing both magnetic susceptibility and magnetization vector inversion techniques. The use of a sparse and blocky norm regularization [0,1,1,1] is well-suited for magnetic susceptibility inversion, while a blocky norm [0000,0000,0000] is the appropriate choice for magnetization vector inversion in our study. Ultimately, the zones characterized by a high magnetic susceptibility and a high magnetization amplitude are considered promising areas for potential Fe-polymetallic occurrences.
]]>Geosciences doi: 10.3390/geosciences13120375
Authors: Ana C Hernández Jorge Sanjurjo-Sánchez Carlos Alves Carlos A. M. Figueiredo
The Barbanza Peninsula (Galicia, NW Spain) is located on the west coast of Galicia. It is a narrow tongue of terrain with an area of 416 km2 and a high altitudinal gradient, with the top having a maximum height of more than 600 m at a distance of less than 5 Km from the sea. As a result of this, there is a significant rainfall gradient (from 900 to more than 3300 mm per year). In the peninsula, there are valuable historical buildings built with granite rock that show variable decay patterns. In this work, we have considered 14 of them, located in several parts of the peninsula, and we have studied their deterioration patterns. Some of them are close to the sea, with sea salt being a possible cause of decay, while for those located far from the sea, the high humidity and rainfall can be the most important cause of decay. A macroscopic study was carried out to determine the deterioration patterns. We have also analyzed the possible role of salts in the decay by using X-ray fluorescence as a screening technique to assess the presence of salts and the possible correlation of salts with the distance to the sea and using scanning electron microscopy to directly identify salts in some of the buildings. The most frequently reported decay is due to lichen growth (biological colonization). Depending on the proximity to the coast, the study area was divided into two zones: zone 1, closer to the sea (<1 km), with an important influence of sea salts and wind, and zone 2, further from the sea, with higher altitudes (center of the peninsula) and important rainfall, humidity, and therefore, biological colonization of stone surfaces. Crusts (to a lesser degree, because it is a mainly rural area) are more frequent in zone 1, but the state of conservation of stone in zone 1 is better than that in zone 2, possibly due to the concentration of urban centers in this zone and more interventions for cleaning stone surfaces. Finally, although we did not observe clear patterns in the appearance of salts in the buildings in agreement with the distance to the sea, we observed different patterns of salts in two of the buildings, one in each zone, which clearly show that, to some extent, salts are involved in decay.
]]>Geosciences doi: 10.3390/geosciences13120374
Authors: Victor Hugo Guimarães Pinto Gianreto Manatschal Anne Marie Karpoff Emmanuel Masini Rodolfo Araújo Victor Adriano Roessler Viana Marc Ulrich
Hyperextended rift systems are characterized by extreme crustal thinning and mantle exhumation associated with extensional detachment faults. These faults cut through thinned continental crust, reaching the underlying mantle and allowing for seawater to infiltrate and react with the crustal and mantle rocks. Hydrothermal fluid systems linked to detachment faults result in fluid–rock reactions occurring along the detachments, resulting in the breakdown and alteration of minerals, loss of elements and strain weakening in both mantle and crustal rocks. We present new geological observations and geochemical data from the modern Iberia and fossil Alpine Tethys Ocean Continent Transition and the West Pyrenean Mauléon hyperextended rift basin. We show evidence for a km-scale fluid flow along detachment faults and discuss the conditions under which fluid flow and mass transfer occurred. Convective fluid systems are of major importance for mass transfer between the mantle, crustal and marine reservoirs. We identified gains in Si, Mg, Fe, Mn, Ca, Ni, Cr and V along extensional detachment faults that we relate to channelized, hydrothermal crust- and mantle-reacted fluid systems migrating along detachments in the hyperextended continental crust. The observation that fault rocks of extensional detachment and syn-extensional sedimentary rocks are enriched in mantle-derived elements such as Cr, Ni and V enables us to define the pathways of fluids, as well as to estimate their age relative to detachment faulting and sedimentation. Because all three examples show a similar mass transport of elements along detachment systems at km-scale, we conclude that these examples are linked to convective fluid systems that may affect the thermal state of the lithosphere, as well as the rheology and chemistry of rocks in hyperextended systems, and may have implications for ore mineral exploration in hyperextended rift systems.
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