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Geosciences
Volume 15
Issue 3
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Geosciences, Volume 15, Issue 3 (March 2025) – 38 articles

Cover Story (view full-size image): In the Betic-Rif Cordilleras, contrary to other sectors of the western Tethys, the Eocene platforms started in the Cuisian after a gap including the Ilerdian. An Eocene succession with gravity flows consisting of turbidites and olistostromes was detected in the Aspe-Terreros Prebetic section (External Betic Zone). In one of the turbidites, we dated the middle Ilerdian, on the basis of LBF, representing a vestige of a missing Illerdian carbonate platform. The microfacies of these deposits rich in LBF have been described and documented. The gap in the sedimentation and absence of Ilerdian platforms in the Betic-Rif have been related to the so-called Eo-Alpine tectonics (Cretaceous to Paleogene) and sea-level variations contemporarily with the establishment of shallow marine realms in the western Tethys. View this paper
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21 pages, 2036 KiB  
Article
Quantifying Natural Hydrogen Generation Rates and Volumetric Potential in Onshore Serpentinization
by Reza Rezaee
Geosciences 2025, 15(3), 112; https://doi.org/10.3390/geosciences15030112 - 20 Mar 2025
Viewed by 251
Abstract
This study explores the generation of natural hydrogen through the serpentinization of onshore ultramafic rocks, highlighting its potential as a clean energy resource. By investigating critical factors such as mineral composition, temperature, and pressure, the research develops an empirical model using multiple regression [...] Read more.
This study explores the generation of natural hydrogen through the serpentinization of onshore ultramafic rocks, highlighting its potential as a clean energy resource. By investigating critical factors such as mineral composition, temperature, and pressure, the research develops an empirical model using multiple regression analysis to predict hydrogen generation rates under varying geological conditions. A novel five-stage volumetric calculation methodology is introduced to estimate hydrogen production from ultramafic rock bodies. The application of this framework to the Giles Complex, an ultramafic-mafic intrusion in Australia, suggests a hydrogen generation potential of approximately 2.24 × 1013 kg of hydrogen through partial serpentinization. This estimate is based on the assumed mineral composition, depth, and temperature conditions within the intrusion, which influence the extent of serpentinization reactions. The findings demonstrate the significant potential of ultramafic complexes for natural hydrogen production and provide a foundation for advancing natural hydrogen exploration, refining predictive models, and supporting sustainable energy development. Full article
(This article belongs to the Section Geochemistry)
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33 pages, 16726 KiB  
Article
Geophysical-Geotechnical Characterization of Mud Volcanoes in Cartagena Colombia
by Guilliam Barboza-Miranda, Andrea Carolina Lopez Macías, Jisseth Valdez-Vargas, Meiker Pérez-Barón, Yamid E. Nuñez de la Rosa, Gustavo Eliecer Florez de Diego, Juan José Carrascal and Jair Arrieta Baldovino
Geosciences 2025, 15(3), 111; https://doi.org/10.3390/geosciences15030111 - 19 Mar 2025
Viewed by 253
Abstract
In this research, the mud diapirism phenomenon in the Membrillal sector in Cartagena is characterized to analyze its spatiotemporal evolution. The goal is to geomorphologically, geotechnically, and geologically characterize the area to zone regions with the greatest susceptibility to geological hazards and provide [...] Read more.
In this research, the mud diapirism phenomenon in the Membrillal sector in Cartagena is characterized to analyze its spatiotemporal evolution. The goal is to geomorphologically, geotechnically, and geologically characterize the area to zone regions with the greatest susceptibility to geological hazards and provide an updated diagnosis of the phenomenon. This study is conducted due to the risks that mud diapirism poses to infrastructure and the safety of local communities. Understanding the behavior of these structures is essential for designing effective mitigation measures and optimizing urban planning in areas affected by this phenomenon. The methodology used includes collecting secondary data and implementing geophysical, geotechnical, and laboratory tests. Among the techniques employed are the Standard Penetration Test (SPT), the excavation of test pits, and electrical resistivity tomography, which revealed mud deposits at different depths. Laboratory studies also evaluated the physical and mechanical properties of the soil, such as Atterberg limits, grain size distribution, moisture content, and expansion tests, in addition to physic-chemical analyses. Among the most relevant findings is the presence of four active mud vents and four mud ears, representing an increase compared to the previous study that only recorded three mud vents. The tests revealed mud deposits at 1.30 m and 10 m depths, consistent with the geotechnical results. Laboratory tests revealed highly plastic soils, with Liquid Limits (LL) ranging from 44% to 93% and Plastic Limits (PL) ranging from 14% to 46%. Soil classification showed various low- and high-plasticity clays (CL and CH) and silty clays (MH), presenting challenges for structural stability and foundation design. Additionally, natural moisture content varied between 15.8% and 89%, and specific gravity ranged from 1.72 to 2.75, reflecting significant differences in water retention and soil density. It is concluded that diapirism has increased in the region, with constant monitoring recommended, and the Territorial Planning Plan (POT) has been updated to include regulations that mitigate the risks associated with urban development in affected areas. Full article
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27 pages, 6595 KiB  
Article
Modeling Flood Susceptibility Utilizing Advanced Ensemble Machine Learning Techniques in the Marand Plain
by Ali Asghar Rostami, Mohammad Taghi Sattari, Halit Apaydin and Adam Milewski
Geosciences 2025, 15(3), 110; https://doi.org/10.3390/geosciences15030110 - 18 Mar 2025
Viewed by 295
Abstract
Flooding is one of the most significant natural hazards in Iran, primarily due to the country’s arid and semi-arid climate, irregular rainfall patterns, and substantial changes in watershed conditions. These factors combine to make floods a frequent cause of disasters. In this case [...] Read more.
Flooding is one of the most significant natural hazards in Iran, primarily due to the country’s arid and semi-arid climate, irregular rainfall patterns, and substantial changes in watershed conditions. These factors combine to make floods a frequent cause of disasters. In this case study, flood susceptibility patterns in the Marand Plain, located in the East Azerbaijan Province in northwest Iran, were analyzed using five machine learning (ML) algorithms: M5P model tree, Random SubSpace (RSS), Random Forest (RF), Bagging, and Locally Weighted Linear (LWL). The modeling process incorporated twelve meteorological, hydrological, and geographical factors affecting floods at 485 identified flood-prone points. The data were analyzed using a geographic information system, with the dataset divided into 70% for training and 30% for testing to build and validate the models. An information gain ratio and multicollinearity analysis were employed to assess the influence of various factors on flood occurrence, and flood-related variables were classified using quantile classification. The frequency ratio method was used to evaluate the significance of each factor. Model performance was evaluated using statistical measures, including the Receiver Operating Characteristic (ROC) curve. All models demonstrated robust performance, with an area under the ROC curve (AUROC) exceeding 0.90. Among the models, the LWL algorithm delivered the most accurate predictions, followed by RF, M5P, Bagging, and RSS. The LWL-generated flood susceptibility map classified 9.79% of the study area as highly susceptible to flooding, 20.73% as high, 38.51% as moderate, 29.23% as low, and 1.74% as very low. The findings of this research provide valuable insights for government agencies, local authorities, and policymakers in designing strategies to mitigate flood-related risks. This study offers a practical framework for reducing the impact of future floods through informed decision-making and risk management strategies. Full article
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18 pages, 8388 KiB  
Article
Updated Chronology of the Last Deglaciation in the Făgăraş Mts (Romania)
by Zoltán Kern, Petru Urdea, Mircea Ardelean, ASTER Team and Zsófia Ruszkiczay-Rüdiger
Geosciences 2025, 15(3), 109; https://doi.org/10.3390/geosciences15030109 - 18 Mar 2025
Viewed by 222
Abstract
So far, published geochronological data poorly constrain the Late Pleistocene glacial fluctuations in the Făgăraş Mts (Southern Carpathians, Romania). The deglaciation chronology in the central Făgăraş Mts is supported by new (n = 5) and recalculated (n = 5) 10Be [...] Read more.
So far, published geochronological data poorly constrain the Late Pleistocene glacial fluctuations in the Făgăraş Mts (Southern Carpathians, Romania). The deglaciation chronology in the central Făgăraş Mts is supported by new (n = 5) and recalculated (n = 5) 10Be exposure ages from a southern and two northern valleys. Cosmic ray exposure (CRE) ages were calculated considering the effects of surface denudation, uplift and snow-shielding. A 10Be exposure age obtained from a glacial landform representing the last glacierets of the central Făgăraş Mts yielded an age of 13.3 ± 1.2 ka. A polished bedrock sample and a moraine boulder constrain the age of a cirque glacier stage to 14.5 ± 1.5 ka, while quite coherent CRE ages from two erratic boulders place the previous stage at ~18.7 ka (18.6 ± 1.7 ka and 18.7 ± 1.7 ka). These glacial stages coincide with major deglaciation stages M4 and M2a reconstructed in the Retezat Mts, derived from comparable CRE ages calculated using the same methodology; however, geomorphological and/or geochronological evidence of the intermediate stages is still not found in the central Făgăraş Mts. All CRE ages gathered from the landforms corresponding to the more extended glacial stages are younger than expected from their morphostratigraphic position and thus considered as minimum age constraints. However, considering the coherent CRE ages of the above morphostratigraphic stage, it is likely that the balanced-budget glaciological conditions corresponding to these more extended stages prevailed before ~19 ka and likely coincided with the cold peaks of the Marine Isotope Stage 2. The currently available in situ 10Be data do not support the existence of a period of glacier advance during the Holocene or Greenland Stadial-1 (Younger Dryas) in the central Făgăraş Mts. Full article
(This article belongs to the Special Issue Geochronology and Chemostratigraphy of Quaternary Environment)
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24 pages, 11232 KiB  
Article
Microstructural Investigation of Variscan Late-Collisional Granitoids (Asinara Island, NW Sardinia, Italy): New Insights on the Relationship Between Regional Deformation and Magma Emplacement
by Diego Pieruccioni, Matteo Simonetti, Salvatore Iaccarino, Chiara Montomoli and Rodolfo Carosi
Geosciences 2025, 15(3), 108; https://doi.org/10.3390/geosciences15030108 - 18 Mar 2025
Viewed by 431
Abstract
In the framework of the geological mapping of sheet “n. 425—Asinara Island” (NW Sardinia, Italy) of the Italian National Geological Mapping Project (CARG Project), three late- to post-collisional Variscan intrusive units are recognized: (i) Castellaccio Unit; (ii) Punta Sabina Unit; and (iii) sheeted [...] Read more.
In the framework of the geological mapping of sheet “n. 425—Asinara Island” (NW Sardinia, Italy) of the Italian National Geological Mapping Project (CARG Project), three late- to post-collisional Variscan intrusive units are recognized: (i) Castellaccio Unit; (ii) Punta Sabina Unit; and (iii) sheeted dyke complex. Granitoid rocks from these intrusive units intruded into the medium- to high-grade metamorphic micaschist and paragneiss and the migmatitic complex. A range of deformation microstructures from sub-magmatic to low-temperature subsolidus conditions are recognized. The main observed microstructures are represented by chessboard patterns in quartz and by feldspar sub-grain rotation dynamic recrystallization, indicative of deformation at high-temperature conditions (T > 650 °C). Solid-state high-temperature deformations (T > 450 °C) are provided by feldspar bulging, myrmekites, quartz grain boundary migration and sub-grain rotation dynamic recrystallization. Low-temperature sub-solidus microstructures (T < 450 °C) consist of quartz bulging, mica kinks, and feldspar twinning and bending. These features highlight that the three intrusive units recorded tectonic stresses, which affected the granitoids during cooling without developing a strong penetrative meso/microstructural fabric, as observed in other sectors of the Variscan orogen. The complete sequence of deformation microstructures, recorded in all intrusive units, suggests a weak but still ongoing deformation regime during granitoid emplacement in the Variscan orogen of northwestern Sardinia. These observations are similar to the features highlighted in other sectors of the southern Variscan belt and suggest a complex interplay between transpressional-induced exhumation of the middle/deep crust and magma intrusion. Full article
(This article belongs to the Special Issue Advances in Structural Geology: From Deformational Processes to Geo-Resource Exploration)
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18 pages, 44550 KiB  
Article
Researching Holocene Sediments at Bac Lieu Offshore, Vietnam with Insights from Near-Surface 2D Reflection Seismic Data
by Dung Quang Nguyen, Cuong Van Anh Le, Thuan Van Nguyen and Tuan Van Huynh
Geosciences 2025, 15(3), 107; https://doi.org/10.3390/geosciences15030107 - 17 Mar 2025
Viewed by 135
Abstract
The high-resolution seismic method can provide acoustic reflectivity images of shallow marine geology structures. In South Vietnam, the demand for construction materials like sand is high; therefore, the exploration of its deposits is considered in this study. This study investigated an around 200-square-kilometer [...] Read more.
The high-resolution seismic method can provide acoustic reflectivity images of shallow marine geology structures. In South Vietnam, the demand for construction materials like sand is high; therefore, the exploration of its deposits is considered in this study. This study investigated an around 200-square-kilometer area offshore Bac Lieu using 2D seismic sub-bottom lines. We employed the processed seismic amplitude and its seismic attributes as mean and variance textures to interpret the data. The processed seismic amplitude and its attributes can represent the young Holocene sediments (i.e., sand, silt, clay, and their mixtures) thanks to their different seismic patterns. Our interpretation result consists of 3D horizons of the seabed, Holocene silt, and sand sediments, which are compatible with the prior geological information, including three nearby drill holes. The seabed gradually descends from 10.0 m to 19.0 m over a horizontal distance of around 11 km. Moreover, the interpreted results show that the sand sediments reside in the center of survey area, with a maximum thickness of around 12.0 m. Interestingly, a fill sediment channel effectively separates two different zones of young Holocene sand and silt sediments. The findings provide valuable information for Vietnamese government officers to develop sustainable policies and regulations for marine mineral exploitation and exploration. Full article
(This article belongs to the Section Sedimentology, Stratigraphy and Palaeontology)
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15 pages, 3616 KiB  
Article
Kinetic Analysis of Carpathian Source Rock Pyrolysis Under Dynamic Conditions
by Małgorzata Labus and Irena Matyasik
Geosciences 2025, 15(3), 106; https://doi.org/10.3390/geosciences15030106 - 16 Mar 2025
Viewed by 304
Abstract
The research presented in the article was undertaken in order to better investigate the generation potential of the Oligocene Menilite Formation due to its importance as source rocks within the Outer Carpathian Basin. The non-isothermal decomposition of the selected Carpathian source rock was [...] Read more.
The research presented in the article was undertaken in order to better investigate the generation potential of the Oligocene Menilite Formation due to its importance as source rocks within the Outer Carpathian Basin. The non-isothermal decomposition of the selected Carpathian source rock was studied to determine the kinetic parameters of the pyrolysis process. The kinetic parameters of bulk rock and separated kerogen were determined using the model-free Kissinger, Kissinger–Akahira–Sunose (KAS), and Friedman methods. The pyrolysis process exhibits a complex reaction mechanism. The obtained apparent activation energy (Ea) and pre-exponential factor (A) values depend on the extent of conversion, suggesting that the process involves multiple reaction steps. This dependence is very similar when calculated using both isoconversional methods, Friedman and KAS; however, the calculated values of the kinetic parameters differ depending on the method used. It was found that the activation energy of kerogen is lower than that of bulk rock, and the reaction maximum was shifted to higher temperatures. This shift is attributed to the presence of clay minerals in the rock. The values of average activation energy and the pre-exponential factor found in this study are relatively high, possibly due to the nature of the short-chain organic matter contained in the source rock. Full article
(This article belongs to the Section Geochemistry)
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19 pages, 31528 KiB  
Article
Evidence of Holocene Sea-Level Rise from Buried Oyster Reef Terrain in a Land-Locked Insular Embayment in Greece
by Evangelia Manoutsoglou and Thomas Hasiotis
Geosciences 2025, 15(3), 105; https://doi.org/10.3390/geosciences15030105 - 16 Mar 2025
Viewed by 335
Abstract
Gera Gulf, a relatively small embayment on the island of Lesvos, serves as a representative example of a semi-enclosed, shallow marine system in Greece. Previous studies revealed that the gulf seafloor is occupied by numerous small reefs that are evenly distributed. Recently, seismic [...] Read more.
Gera Gulf, a relatively small embayment on the island of Lesvos, serves as a representative example of a semi-enclosed, shallow marine system in Greece. Previous studies revealed that the gulf seafloor is occupied by numerous small reefs that are evenly distributed. Recently, seismic surveys together with gravity coring have shown numerous relict reefs within a fine-grained matrix, hosted at different stratigraphic levels above the inferred Holocene/Pleistocene boundary and locally extending up to the present seabed. The reefs are primarily engineered by the bivalve Ostrea edulis, with additional colonization by other marine organisms such as the coral Cladocora caespitosa. Key features identified in the seismic profiles include the widespread distribution of buried reef structures, erosional surfaces and unconformities also related to a paleolake, extensive fluid concentrations, and a major fault system paralleling the northeastern coast. Seismic record analysis and sediment dating suggest that the flooding of Gera Gulf began approximately 7500 BP, with O. edulis colonizing the seabed shortly thereafter. Buried reef structures were identified within the transgressive and highstand system tracts, characterized by varying sedimentation rates. These variations reflect changing environmental conditions, probably linked to specific climatic events during the Holocene epoch, which contributed to the evolution and shaping of the oyster reef terrain. Given the limited studies on recent or buried oyster reefs in similar environments, this study provides critical insights into the Holocene evolution of oyster reef terrains and their response to climate changes. Full article
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28 pages, 6201 KiB  
Article
Vegetation Monitoring of Palm Trees in an Oasis Environment (Boudenib, Morocco) Using Automatic Processing of Medium-Resolution Remotely Sensed Data
by Kaoutar Badioui, Ann Van Griensven and Boud Verbeiren
Geosciences 2025, 15(3), 104; https://doi.org/10.3390/geosciences15030104 - 15 Mar 2025
Viewed by 253
Abstract
Oases are part of the natural wealth and heritage of Morocco and contribute to the social, economic, and touristic environment. Morocco has lost more than 2/3 of its oases during the past century due to water scarcity, succession of drought periods, climate change [...] Read more.
Oases are part of the natural wealth and heritage of Morocco and contribute to the social, economic, and touristic environment. Morocco has lost more than 2/3 of its oases during the past century due to water scarcity, succession of drought periods, climate change and over-exploitation of groundwater resources. Palm trees are strongly dependent on irrigation and availability of surface water as soon as the water table depth falls below the root zone of 9 m. Improving management and monitoring of oasis ecosystems is strongly encouraged by UNESCO Biosphere Reserve and RAMSAR guidelines. The Boudenib and Tafilalet oases are among the biggest palm groves located in the south-eastern part of Morocco. These oases belong to catchments of the rivers Guir and Ziz, respectively. This paper uses remotely sensed data from PROBA-V for monitoring vegetation in oases, and linking vegetation characteristics to water availability, water management and quality and quantity of date crops. The Normalized Differential Vegetation Index (NDVI) derived from optical images provides a good estimation of changes in vegetation cover over time. Images of various spatial resolutions (100 m, 300 m and 1 km) obtained with the frequently revisiting Belgian satellite PROBA-V and available since 2014, can be successfully used for deriving time series of vegetation dynamics. TREX—Tool for Raster data Exploration—is a Python-GDAL processing tool of PROBA-V NDVI images for analyzing vegetation dynamics, developed at the Vrije Universiteit Brussel and available online. TREX has various applications, but the main functionality is to provide an automatic processing of PROBA-V satellite images into time series of NDVI and LAI, used in vegetation monitoring of user-defined points of interest. This study presents the results of application of TREX in the arid ecosystems of the Boudenib oasis for the period 2014–2018. The resulting NDVI and LAI time series are also compared to time series of groundwater depth and date crops quantity and quality. Low LAI is observed when water depth is low, and the palm trees lose their greenery. Low LAI is also correlated to low quantity and quality of dates in October 2015 and October 2017. PROBA-V images can therefore be used for monitoring the health of palm trees in oasis environments. However, considering the fact that the PROBA-V satellite mission has ended, this approach could instead be applied to Sentinel-3 data using the same analysis. These results have important implications for water management in the area and can help decision-makers to make better decisions about prevention of water scarcity in the region. Full article
(This article belongs to the Special Issue Earth Observation by GNSS and GIS Techniques)
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17 pages, 6558 KiB  
Article
Outcrop-Scale Hydraulic Fracturing Experiments with a Coagulable Resin and Data Analysis Results
by Tsutau Takeuchi, Akira Fujimoto, Ryohei Inoue, Tsuyoshi Ishida, Takashi Danjo, Tatsuya Yokoyama and Hirokazu Fujii
Geosciences 2025, 15(3), 103; https://doi.org/10.3390/geosciences15030103 - 14 Mar 2025
Viewed by 273
Abstract
Hydraulic fracturing is a crucial technology for resource development, such as shale gas, and its optimization is necessary to enhance development efficiency. However, evaluating fracture shapes involves technical uncertainties. Japan Organization for Metals and Energy Security (JOGMEC) and Kyoto University have conducted laboratory-scale [...] Read more.
Hydraulic fracturing is a crucial technology for resource development, such as shale gas, and its optimization is necessary to enhance development efficiency. However, evaluating fracture shapes involves technical uncertainties. Japan Organization for Metals and Energy Security (JOGMEC) and Kyoto University have conducted laboratory-scale hydraulic fracturing experiments using coagulable fluorescent resin as the injection fluid (resin fracturing test) to visualize hydraulic fractures and investigate their relationship with acoustic emissions (AEs) generated during fracturing. Since lab-scale experiments can only examine the phenomena near the injection hole owing to size limitations, we designed an experiment to apply the visualization method to the outcrop scale. This paper presents the results from an in situ, outcrop-scale hydraulic fracturing experiment conducted at the Kamioka Mine, Gifu Prefecture, Japan, from 2022 to 2023, with goals similar to those of the laboratory experiments. A resin fracturing borehole (RF1) with a diameter of 76 mm was core-drilled to a depth of approximately 10 m for the resin fracturing tests. AEs were observed in five boreholes drilled around RF1 at the same depth. Resin fracturing tests were performed at two different depths, with breakdown confirmed at both. A core of a larger diameter (205 mm) was recovered by coaxial overcoring around RF1, and resin-filled fractures were observed under black light on the core surfaces. After the resin fracturing experiment, two analyses were performed using the acquired core and AE data to predict the fracture extension and the mechanism of AE occurrence. We compared the distribution of AE events and visualized fractures in the core. Additionally, we compared the stress direction estimated from failure mechanism analysis using AE data with the maximum stress direction estimated from hydraulic fracturing. Our analysis provided several insights into fracture extension. The distribution of AE hypocenters was consistent with the direction of the hydraulic fractures confirmed by coring after the resin fracturing test. The failure mechanisms are classified based on the polarity of the first P-wave motion of the AE waveform. However, the actual scale of oil fields is significantly larger than that considered in this study. Discussing visible fractures created by hydraulic fracturing is deemed meaningful. We expect that the results of this study will provide valuable information for the precise estimation of hydraulic fractures. Full article
(This article belongs to the Special Issue Fracture Geomechanics—Obstacles and New Perspectives)
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23 pages, 7375 KiB  
Article
Evidence of High-Shear-Velocity Anomalies Inside the Pacific LLSVP
by Rafael Abreu, Mariano S. Arnaiz-Rodríguez and Chahana Nagesh
Geosciences 2025, 15(3), 102; https://doi.org/10.3390/geosciences15030102 - 14 Mar 2025
Viewed by 160
Abstract
We present the evidence of high-velocity regions within the Pacific Large Low Seismic Velocity Province (LLSVP), uncovered using the Virtual Receiver Approach (VRA), a novel seismic imaging method that allows us to determine local absolute velocity values of a non-reflecting body wave that [...] Read more.
We present the evidence of high-velocity regions within the Pacific Large Low Seismic Velocity Province (LLSVP), uncovered using the Virtual Receiver Approach (VRA), a novel seismic imaging method that allows us to determine local absolute velocity values of a non-reflecting body wave that are independent of any assumed Earth model. Our results reveal a complex dynamics of high- and low-velocity regions within the Pacific LLSVP. While low-shear-wave velocities dominate, consistent with the traditionally understood nature of LLSVPs, we identify distinct high-velocity anomalies—an observation not previously reported in this region. We interpret these anomalies as lateral compositional variations within the LLSVP. Petrological modeling suggests that high-velocity regions are associated with low FeO content, potentially linked to the inclusion of post-perovskite material driven by mantle convection. Alternatively, remnants of subducted oceanic crust (e.g., Mid-Ocean Ridge Basalts) could also explain the observed features. Conversely, low-velocity anomalies correspond to FeO-rich compositions. Our findings highlight the thermochemical heterogeneity of the LLSVP, revealing a more complex internal structure than previously thought. The application of the VRA is able to resolve fine-scale structures that have remained as some of the biggest challenges in global tomographic models. Full article
(This article belongs to the Special Issue Seismology of the Dynamic Deep Earth)
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25 pages, 21866 KiB  
Article
The May 2023 Rainstorm-Induced Landslides in the Emilia-Romagna Region (Northern Italy): Considerations from UAV Investigations Under Emergency Conditions
by Luca Schilirò, Alessandro Bosman, Grazia Maria Caielli, Angelo Corazza, Stefano Crema, Cristina Di Salvo, Iolanda Gaudiosi, Marco Mancini, Gianluca Norini, Edoardo Peronace, Federica Polpetta, Maurizio Simionato, Francesco Stigliano, Chiara Varone and Paolo Tommasi
Geosciences 2025, 15(3), 101; https://doi.org/10.3390/geosciences15030101 - 13 Mar 2025
Viewed by 240
Abstract
Rainstorm-induced landslides are a widespread geomorphological hazard that can lead to major emergencies, causing severe damage to life and property. Due to the extent of the areas usually affected by these phenomena (up to thousands of km2) and/or their typical high [...] Read more.
Rainstorm-induced landslides are a widespread geomorphological hazard that can lead to major emergencies, causing severe damage to life and property. Due to the extent of the areas usually affected by these phenomena (up to thousands of km2) and/or their typical high areal density, in the early stages of the emergency it can be useful to reconstruct a comprehensive, albeit preliminary, overview of the landslides. With this aim, in this work we provide an outline of the landslides that occurred in the eastern part of the Emilia-Romagna region (northern Italy) after two severe rainstorms in May 2023. By combining information collected during the emergency through direct field inspections and UAV (unmanned aerial vehicle) surveys with preliminary analyses of historical rainfall/landslide data, we inferred the main characteristics of the landslides (e.g., movement type, involved materials, triggering mechanisms) and the relation with antecedent landslide phenomena, rainfall exceptionality, and anthropogenic activities. The latter were found to have likely contributed to landslides triggering by increasing water discharge and, in turn, infiltration and runoff erosion (i.e., inadequate drainage devices) and steepening slope gradients (e.g., road cuts). The vastness of the territory hit by the May 2023 landslides and their exceptional areal density can be explained not only with the extreme rainfall intensity (>500 years at several rainfall stations), but also with the widespread occurrence of slope materials which are very sensitive to sudden changes in hydraulic conditions. The high landslide susceptibility of the area is confirmed by the fact that many of the May 2023 landslides occurred at or close to previously identified and mapped landslide sites. Full article
(This article belongs to the Special Issue Remote Sensing Monitoring of Geomorphological Hazards)
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14 pages, 3532 KiB  
Article
Public Discourse Surrounding the 2025 California Wildfires: A Sentiment and Topic Analysis of High-Engagement YouTube Comments
by Dmitry Erokhin
Geosciences 2025, 15(3), 100; https://doi.org/10.3390/geosciences15030100 - 11 Mar 2025
Viewed by 410
Abstract
This study explores public discourse surrounding the January 2025 California wildfires by analyzing high-engagement YouTube comments. Leveraging sentiment analysis, misinformation detection, and topic modeling, this research identifies dominant emotional tones, thematic patterns, and the prevalence of misinformation in discussions. The results show a [...] Read more.
This study explores public discourse surrounding the January 2025 California wildfires by analyzing high-engagement YouTube comments. Leveraging sentiment analysis, misinformation detection, and topic modeling, this research identifies dominant emotional tones, thematic patterns, and the prevalence of misinformation in discussions. The results show a predominantly neutral to positive sentiment, with notable emotional intensity in misinformation-related comments, which were rare but impactful. The thematic analysis highlights concerns about governance, environmental issues, and conspiracy theories, including water mismanagement and diversity-related critiques. These findings provide insights for crisis communication, policymaking, and misinformation management during disasters, emphasizing the importance of aligning strategies with public concerns. Full article
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31 pages, 40437 KiB  
Article
Structural Characterization of the Pan-African Banyo Area (Western Cameroon Domain): Constraints from Field Observations, Structures and AMS
by Alys Calore Mengou, Bertille Edith Bella Nke, Théophile Njanko, Pierre Rochette, Roland Kanse Onana, François Demory and Emmanuel Njonfang
Geosciences 2025, 15(3), 99; https://doi.org/10.3390/geosciences15030099 - 10 Mar 2025
Viewed by 186
Abstract
The Banyo area, located in the southern prolongation of the Mayo Nolti shear zone trend, belongs to the western Cameroon domain of the Neoproterozoic Central African Belt (NCAB). It is made of granitic rocks that intrude metamorphic banded rocks. Both are sometimes mylonitized. [...] Read more.
The Banyo area, located in the southern prolongation of the Mayo Nolti shear zone trend, belongs to the western Cameroon domain of the Neoproterozoic Central African Belt (NCAB). It is made of granitic rocks that intrude metamorphic banded rocks. Both are sometimes mylonitized. The pluton is dominantly of paramagnetic behavior, as shown by the hysteresis loops and the Fe-bearing silicates crystals are the susceptibility carriers. AMS ellipsoids are dominantly of oblate shape, pointing to the importance of flattening during pluton emplacement. The anisotropy degree of magnetic susceptibility values (≤1.20) characterize the magmatic fabric flow. The microstructural study of the granite reveals magmatic, sub-magmatic, solid-state and mylonitic deformations. Field and AMS fabrics show evidence of polyphase deformation (D1–D3). The D1 phase is of flattening mechanism (flat-laying foliation). The D2 phase points to sinistral ductile simple shear accommodating moderate to steep dipping and N-S- to NW-SE-oriented foliations in plutonic and country rocks and conjugated E-W mylonitic foliation in country rocks bearing sub-horizontal- to moderate-plunge mineral stretching lineation. The D3 phase is of dextral ductile simple shear. σ- and δ-type kinematic markers in the pluton indicate sinistral top-to-south sense of shear movement, indicating a non-coaxial component of the tectonics. The magnetic fabrics of the pluton are parallel to those of the D2 deformation phase of the study area. The transpressive D2 and D3 events correlate with the D2 and D3 phases of the Pan-African tectonic dated at 613–585 Ma and 585–540 Ma, respectively. The pluton, then, emplaced during regional sinistral D2 deformation under transpressive regime. The emplacement of the NE Banyo granite took place as rock strips sheared in sinistral sense of shear movement. Full article
(This article belongs to the Section Structural Geology and Tectonics)
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22 pages, 4481 KiB  
Article
Analysis of Vertical Heterogeneity Measures Based on Routine Core Data of Sandstone Reservoirs
by Mohamed S. El Sharawy
Geosciences 2025, 15(3), 98; https://doi.org/10.3390/geosciences15030098 - 9 Mar 2025
Viewed by 428
Abstract
Heterogeneous reservoirs are prevalent; otherwise, they are rare. The problem is detecting the degree of such heterogeneity, which has a significant impact on hydrocarbon production in oilfields. Several vertical heterogeneity measures were introduced to accomplish this task. The coefficient of variation (CV [...] Read more.
Heterogeneous reservoirs are prevalent; otherwise, they are rare. The problem is detecting the degree of such heterogeneity, which has a significant impact on hydrocarbon production in oilfields. Several vertical heterogeneity measures were introduced to accomplish this task. The coefficient of variation (CV), the Dykstra–Parsons coefficient (VDP), and the Lorenz coefficient (LC) are the most common static vertical heterogeneity measures. This study aimed to review these heterogeneity measures, explained how the probability of the permeability distribution affects calculations of heterogeneity measures, explained how involving the porosity affects calculations, and explained how uncertainty in VDP values affects the estimation of cumulative oil production. In this study, 1022 plug core samples from seven wells in different sandstone reservoirs were used. The results reveal that the permeability is log-normally distributed; thus, the CV is calculated based on the variance only. The outliers have a significant effect on the values of the CV. The studied reservoirs are extremely heterogeneous, as evidenced by the VDP. The proposed straight line resulting from the Dykstra–Parsons plot is rarely encountered. Weighting the central points more than the points at the tails gives VDP values similar to those obtained from the data. An uncertainty in the VDP values could have a considerable effect on the calculations of the cumulative oil production. The study also shows that including porosity in the calculation of the LC leads to a decrease in the LC values. The magnitude of the decrease is contingent upon the degree of reservoir heterogeneity and the average porosity. Above LC > 0.7, the reservoir could be extremely heterogeneous. Full article
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17 pages, 1794 KiB  
Article
Spatial Variability in Geotechnical Properties Within Heterogeneous Lignite Mine Spoils
by Ioannis E. Zevgolis, Alexandros I. Theocharis and Nikolaos C. Koukouzas
Geosciences 2025, 15(3), 97; https://doi.org/10.3390/geosciences15030097 - 8 Mar 2025
Viewed by 275
Abstract
During surface coal mining, vast amounts of overburden waste materials—called spoils—are excavated and dumped, forming massive heaps, the sustainable exploitation of which is a top priority globally. This study addresses the advanced geotechnical characterization of spoil materials, focusing on lignite mine spoil heaps, [...] Read more.
During surface coal mining, vast amounts of overburden waste materials—called spoils—are excavated and dumped, forming massive heaps, the sustainable exploitation of which is a top priority globally. This study addresses the advanced geotechnical characterization of spoil materials, focusing on lignite mine spoil heaps, which are often ignored due to their highly heterogeneous nature. This research quantifies the spatial variability in spoil materials from a large heap in Greece, highlighting the importance of a robust geotechnical framework for their effective reclamation. Using statistical analysis and variogram modeling, the scale of fluctuation (SoF) was derived for both the vertical and horizontal directions. The SoF values for spoil properties are found to be on the high end of the natural soil range. Vertical correlations are observed for distances over 10 m, occasionally reaching 20 m, indicating significant spatial variability; in the horizontal direction, the SoF reaches up to 285 m. These findings suggest that spoil elements exhibit important spatial dependence, which is critical for their proper design and exploitation. The results provide a basis for future research and the use of advanced numerical tools, such as the random finite element method, to support geotechnical design and the sustainable exploitation of spoil heaps. Full article
(This article belongs to the Section Geomechanics)
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16 pages, 4638 KiB  
Article
A 34-Year Record of Seismic Activity on Vulcano Island, Italy
by Susanna Falsaperla, Salvatore Spampinato, Ornella Cocina and Giovanni Barreca
Geosciences 2025, 15(3), 96; https://doi.org/10.3390/geosciences15030096 - 8 Mar 2025
Viewed by 382
Abstract
Following the abrupt geochemical and geophysical variations that occurred on the island of Vulcano in September 2021, the search for previous multidisciplinary data on decades-long time spans became necessary to contextualize the newly recorded anomalous variations, which represented a serious threat for the [...] Read more.
Following the abrupt geochemical and geophysical variations that occurred on the island of Vulcano in September 2021, the search for previous multidisciplinary data on decades-long time spans became necessary to contextualize the newly recorded anomalous variations, which represented a serious threat for the local population. Our analyses of ‘vintage’ reports, old documents and analogue seismograms, broaden our understanding of crustal seismic activity. The results unravel the predominant role of Vulcano’s hydrothermal system with respect to tectonic processes in the generation of seismicity in the analyzed sector. Earthquakes were generally located offshore and achieved a maximum M4.6. A 2D strain release map and DBSCAN application highlight seismogenic volumes to the NW, SW and E offshore of the island and trending NNW-SSE inshore, in agreement with structural patterns. Two major volcano unrests in 1985 and 1988 had seismicity mostly confined to the island. In comparison, the longer duration and typology of seismic signals recorded between 2021 and 2022 make this latest episode peculiar in the context of Vulcano’s past seismic activity. Full article
(This article belongs to the Section Geophysics)
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21 pages, 16865 KiB  
Article
Unraveling the Spatio-Temporal Evolution of the Ranchería Delta (Riohacha, Colombia): A Multi-Period Analysis Using GIS
by Marta Fernández-Hernández, Luis Iglesias, Jairo R. Escobar Villanueva and Ricardo Castedo
Geosciences 2025, 15(3), 95; https://doi.org/10.3390/geosciences15030095 - 8 Mar 2025
Viewed by 284
Abstract
The Ranchería River delta, located in Riohacha, Colombia, exemplifies the complex dynamics of coastal systems influenced by environmental and anthropogenic factors. This study analyzes the spatial and temporal evolution of the delta’s shoreline over the past two decades (2003–2023) using Google Earth imagery, [...] Read more.
The Ranchería River delta, located in Riohacha, Colombia, exemplifies the complex dynamics of coastal systems influenced by environmental and anthropogenic factors. This study analyzes the spatial and temporal evolution of the delta’s shoreline over the past two decades (2003–2023) using Google Earth imagery, the Digital Shoreline Analysis System (DSAS) within a GIS environment, and statistical methods such as ANOVA and Tukey’s test. Satellite images from 2003 to 2023 were processed to evaluate shoreline evolution through metrics like the Net Shoreline Movement (NSM) and Linear Regression Rate (LRR). The results reveal a predominant trend of accretion, with values reaching up to 260 m of NSM, particularly between 2003 and 2018. However, the 2018–2023 period shows a shift toward stabilization and localized erosion (e.g., the NSM ranges from 96 m of erosion to 32 m of accretion), with significant changes in the northeastern area (the delta’s Santa Rita arm) attributed to anthropic and natural factors (e.g., absence of mangroves or ongoing human activities). The comparison of LRR and NSM values reveals consistent linearity in shoreline behavior across the study period, suggesting stable coastal processes during accretion-dominated phases and increased variability during recent erosion. Variability across zones highlights the role of natural barriers like mangroves in mitigating erosion. The findings underscore the importance of integrating long-term data with recent trends for shoreline management and emphasize adaptive strategies to conserve critical ecosystems while addressing the socio-economic needs of local communities. Full article
(This article belongs to the Special Issue Socioeconomic Resilience to Climate Change in Coastal Regions)
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24 pages, 6288 KiB  
Article
Records of Ground Deformation in Northern Kefalonia Inferred from Cosmogenic 36Cl Geochronology
by Constantin D. Athanassas, Regis Braucher, Ioannis Vakalas and George Apostolopoulos
Geosciences 2025, 15(3), 94; https://doi.org/10.3390/geosciences15030094 - 7 Mar 2025
Viewed by 355
Abstract
This study presents the first direct cosmogenic 36Cl-based chronology of landscape evolution and ground deformation in the Ionian Islands, focusing on the Thinia Valley in northern Kefalonia, western Greece. At the Zola site, exposure ages indicate that the eastern limb of the [...] Read more.
This study presents the first direct cosmogenic 36Cl-based chronology of landscape evolution and ground deformation in the Ionian Islands, focusing on the Thinia Valley in northern Kefalonia, western Greece. At the Zola site, exposure ages indicate that the eastern limb of the associated anticline has undergone intermittent deformation since at least 34 ka, with ongoing exhumation still occurring today. Variability in erosion rates suggests a complex deformation history, with lower-elevation samples exhuming faster than those at higher elevations. The findings highlight the role of progressive landslide activity rather than a single catastrophic failure. The compression-induced asymmetry of the Zola anticline, along with regional seismicity, appears to control slope instability. The exposure ages at the SK site reveal a surface that reached steady-state long before 20 ka, with a uniform erosion rate of 47.72 ± 0.82 m·Ma−1, consistent with regional estimates. Additionally, a prehistoric earthquake—dated at 4.8 ± 0.14 ka—has been identified, with a planar surface exhumed in a single slip event. These findings emphasize the tectonic mobility of the region, with deformation processes persisting since the Middle Pleistocene. The results contribute to a broader understanding of fault-controlled slope instability and have direct implications for seismic hazard assessment in actively deforming terrains. Full article
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16 pages, 3109 KiB  
Article
A Machine Learning Classification Approach to Geotechnical Characterization Using Measure-While-Drilling Data
by Daniel Goldstein, Chris Aldrich, Quanxi Shao and Louisa O'Connor
Geosciences 2025, 15(3), 93; https://doi.org/10.3390/geosciences15030093 - 7 Mar 2025
Viewed by 302
Abstract
Bench-scale geotechnical characterization often suffers from high uncertainty, reducing confidence in geotechnical analysis on account of expensive resource development drilling and mapping. The Measure-While-Drilling (MWD) system uses sensors to collect the drilling data from open-pit blast hole drill rigs. Historically, the focus of [...] Read more.
Bench-scale geotechnical characterization often suffers from high uncertainty, reducing confidence in geotechnical analysis on account of expensive resource development drilling and mapping. The Measure-While-Drilling (MWD) system uses sensors to collect the drilling data from open-pit blast hole drill rigs. Historically, the focus of MWD studies was on penetration rates to identify rock formations during drilling. This study explores the effectiveness of Artificial Intelligence (AI) classification models using MWD data to predict geotechnical categories, including stratigraphic unit, rock/soil strength, rock type, Geological Strength Index, and weathering properties. Feature importance algorithms, Minimum Redundancy Maximum Relevance and ReliefF, identified all MWD responses as influential, leading to their inclusion in Machine Learning (ML) models. ML algorithms tested included Decision Trees, Support Vector Machines (SVMs), Naive Bayes, Random Forests (RFs), K-Nearest Neighbors (KNNs), Linear Discriminant Analysis. KNN, SVMs, and RFs achieved up to 97% accuracy, outperforming other models. Prediction performance varied with class distribution, with balanced datasets showing wider accuracy ranges and skewed datasets achieving higher accuracies. The findings demonstrate a robust framework for applying AI to real-time orebody characterization, offering valuable insights for geotechnical engineers and geologists in improving orebody prediction and analysis Full article
(This article belongs to the Special Issue Digging Deeper: Insights and Innovations in Rock Mechanics)
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19 pages, 9739 KiB  
Article
Rockfall Hazard Evaluation in a Cultural Heritage Site: Case Study of Agia Paraskevi Monastery, Monodendri, Greece
by Spyros Papaioannou, George Papathanassiou and Vassilis Marinos
Geosciences 2025, 15(3), 92; https://doi.org/10.3390/geosciences15030092 - 7 Mar 2025
Viewed by 133
Abstract
Rockfall is considered the main geohazard in mountainous areas with steep morphology. The main objective of this study is to assess the rockfall hazard in the cultural heritage site of the Monastery of Agia Paraskevi, Monodendri, in northern Greece, where a recent rockfall [...] Read more.
Rockfall is considered the main geohazard in mountainous areas with steep morphology. The main objective of this study is to assess the rockfall hazard in the cultural heritage site of the Monastery of Agia Paraskevi, Monodendri, in northern Greece, where a recent rockfall event occurred, destroying a small house and the protective fence constructed to protect the Monastery of Agia Paraskevi. To evaluate the rockfall potential, engineering geological-oriented activities were carried out, such as geostructurally oriented field measurements, aiming to simulate the rockfall path and to compute the kinetic energy and the runout distance. In addition, using remote sensing tools such as Unmanned Aerial Vehicles (UAVs), we were able to inspect the entire slope face and detect the locations of detached blocks by measuring their volume. As a result, it was concluded that the average volume of the expected detached blocks is around 1.2 m3, while the maximum kinetic energy along a rockfall trajectory ranges from 1850 to 2830 kJ, depending on the starting point (source). Furthermore, we discussed the level of similarity between the outcomes arising from the data obtained by the traditional field survey and the UAV campaigns regarding the structural analysis of discontinuity sets. Full article
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16 pages, 6107 KiB  
Article
Analysis of Groundwater Storage at The Local Scale in the Missan Region, Iraq, Based on GRACE Satellite and Well Data
by Hanan K. Mohammed, Mahmoud S. Al-Khafaji and Imzahim A. Alwan
Geosciences 2025, 15(3), 91; https://doi.org/10.3390/geosciences15030091 - 3 Mar 2025
Viewed by 297
Abstract
Accurate data collection and time series creation are crucial for understanding these changes. However, many areas lack reliable data due to geopolitical issues and government permissions. Urgent action is needed for sustainable water management. This study uses Gravity Recovery and Climate Experiment (GRACE) [...] Read more.
Accurate data collection and time series creation are crucial for understanding these changes. However, many areas lack reliable data due to geopolitical issues and government permissions. Urgent action is needed for sustainable water management. This study uses Gravity Recovery and Climate Experiment (GRACE) data to analyze monthly fluctuations in groundwater storage in the Missan region of Iraq from January 2022 to December 2023, using Goddard Space Flight Center (GSFC) mascon, Jet Propulsion Laboratory Downscaled (JPL_D), and Catchment Land Surface Model (CLSM). This study revealed the variability in GWS over the area using RS data and in integration with available monitoring wells. To investigate GWS variability, GSFC, JPL_D, and CLSM observed a downward trend in GWS in 2022; GSFC exhibits the highest negative groundwater trend, while CLSM has the lowest negative trend. Then, from January to June 2023, GSFC had the highest positive trend, while CLSM had the lowest positive trend. Most of the study period has a negative trend for remote sensing that matches the monitoring well data in situ, in which wells 1, 2, and 4 are negative trends of the study period. In conclusion, these results improve the role of remote sensing in groundwater monitoring in small-scale region unconfined aquifers, which supports decision-making in water resource management. The findings illustrated a match between the results derived from the GRACE data and monitoring well data. Full article
(This article belongs to the Section Hydrogeology)
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19 pages, 18181 KiB  
Article
Modeling and Design Aspects of Shallow Geothermal Energy Piles—A Case Study on Large Commercial Building Complex in Zagreb, Croatia
by Marija Macenić and Tomislav Kurevija
Geosciences 2025, 15(3), 90; https://doi.org/10.3390/geosciences15030090 - 1 Mar 2025
Viewed by 328
Abstract
With ambitious targets set by the EU for the reduction of emissions from the energy sector by 2030, there is a need to design and develop more building projects using renewable energy sources. Even though in Europe, heating and cooling share from renewable [...] Read more.
With ambitious targets set by the EU for the reduction of emissions from the energy sector by 2030, there is a need to design and develop more building projects using renewable energy sources. Even though in Europe, heating and cooling share from renewable resources is increasing, and in 2021, the total share in this sector in Croatia was at 38%, the share of heat production by heat pumps is rather low. One possibility to increase this share is to install energy piles when constructing a building, which is becoming an increasingly common practice. This case study focuses on such a system designed for a large, non-residential building in Zagreb, Croatia. The complex was designed as 13 separate dilatations, with central heating and cooling of all facilities, covered by 260 energy piles (130 pairs in serial connection), with a length of the polyethylene pipe of 20 m in a double loop inserted within the pile. The thermo-technical system was designed as a bivalent parallel system, with natural gas covering peak heating loads and a dry cooler covering cooling peak loads when the loads cannot be covered only by ground-source heat pumps. In the parallel bivalent system, the geothermal source will work with a much higher number of working hours at full load than is the case for geothermal systems that are dimensioned to peak consumption. Therefore, the thermal response test was conducted on two energy piles, connected in series, to obtain thermogeological parameters and determine the heat extraction and rejection rates. The established steady-state heat rate defines the long-term ability to extract heat energy during constant thermal load, with the inlet water temperature from the pile completely stabilized, i.e., no significant further sub-cooling is achieved in the function of the geothermal field operation time. Considering the heating and cooling loads of the building, modeling of the system was performed in such a manner that it utilized renewable energy as much as possible by finding a bivalent point where the geothermal system works efficiently. It was concluded that the optimal use of the geothermal field covers total heating needs and 70% for cooling, with dry coolers covering the remaining 30%. Additionally, based on the measured thermogeological parameters, simulations of the thermal response test were conducted to determine heat extraction and rejection rates for energy piles with various geometrical parameters of the heat exchanger pipe and fluid flow variations. Full article
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27 pages, 13194 KiB  
Article
Petrographic Analysis of Mafic and Ultramafic Rocks in Northern Thailand: Implications for CO2 Mineralization and Enhanced Rock Weathering Approach
by Tadsuda Taksavasu
Geosciences 2025, 15(3), 89; https://doi.org/10.3390/geosciences15030089 - 1 Mar 2025
Viewed by 772
Abstract
Mafic and ultramafic rocks have become a promising approach for atmospheric carbon dioxide (CO2) reduction, as they are major sources of CO2-reactive minerals, i.e., olivine, pyroxene, plagioclase, and serpentine. The minerals potentially sequester CO2 by turning it into [...] Read more.
Mafic and ultramafic rocks have become a promising approach for atmospheric carbon dioxide (CO2) reduction, as they are major sources of CO2-reactive minerals, i.e., olivine, pyroxene, plagioclase, and serpentine. The minerals potentially sequester CO2 by turning it into a stable solid phase through carbon mineralization in the rock weathering process. However, detailed descriptions and evaluations of the target formations are lacking. This study investigates the mineralogical composition and microtextural characteristics of representative mafic and ultramafic rocks observed in northern Thailand, using a petrographic analysis. The results show that variations in CO2-reactive mineral assemblages of rocks certainly affect their theoretical CO2 uptake potential. Ultramafic rocks tend to sequester larger amounts of CO2 than mafic rocks. The microtextural observation reveals the mineral size ranges of 0.05–5 mm for ultramafic and mafic intrusive rocks and 0.01–2 mm for mafic extrusive and metamorphosed rocks. Reducing the rock size to be equal to the average size of the reactive minerals could be considered one of the practical designs in enhanced rock weathering activities. Understanding the mineralogical and textural characteristics of target rocks thus plays a crucial role in further georesource exploration and engineering designs, supporting climate action strategies on various scales. Full article
(This article belongs to the Section Geochemistry)
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26 pages, 10461 KiB  
Article
Modeling ANN-Based Estimations of Probabilistic-Based Failure Soil Depths for Rainfall-Induced Shallow Landslides Due to Uncertainties in Rainfall Factors
by Shiang-Jen Wu, Syue-Rou Chen and Cheng-Der Wang
Geosciences 2025, 15(3), 88; https://doi.org/10.3390/geosciences15030088 - 1 Mar 2025
Viewed by 152
Abstract
In this study, an ANN-derived innovative model was developed for estimating the failure soil depths of rainfall-induced shallow landslide events, named the SM_EFD_LS model. The proposed SM_EFD_LS model was created using the modified ANN model via the genetic algorithm calibration approach (GA-SA) with [...] Read more.
In this study, an ANN-derived innovative model was developed for estimating the failure soil depths of rainfall-induced shallow landslide events, named the SM_EFD_LS model. The proposed SM_EFD_LS model was created using the modified ANN model via the genetic algorithm calibration approach (GA-SA) with multiple transfer functions (MTFs) (ANN_GA-SA_MTF) with a significant number of failure soil depths and corresponding rainfall factors. Ten shallow landslide-susceptible spots in the Jhuokou watershed in southern Taiwan were selected as the study area. The associated 1000 simulations of rainfall-induced shallow landslide events were used in the model’s development and validation. The model validation results indicate that the validated failure soil depths are mainly located within the resulting 60% confidence intervals from the proposed SM_EFD_LS model. Moreover, the estimated failure depths resemble the validated ones, with acceptable averages of the absolute error (RMSE) and relative error (MRE) (11 cm and 0.06) and a high model reliability index of 1.2. In the future, the resulting probabilistic-based failure soil depths obtained using the proposed SM_EFD_LS model could be introduced with the desired reliability needed for early landslide warning and prevention systems. Full article
(This article belongs to the Special Issue Landslide Susceptibility Mapping, Hazard Assessment and Risk Evaluation)
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15 pages, 7725 KiB  
Article
A Descriptive Analysis of the Morphology and Movement of the Golden Gate Sand Waves
by Daniel M. Hanes
Geosciences 2025, 15(3), 87; https://doi.org/10.3390/geosciences15030087 - 1 Mar 2025
Viewed by 278
Abstract
High-resolution bathymetric surveys are interpreted to describe the morphology and movement of a field of sand waves near San Francisco, CA, USA. The sand wave size, shape, orientation, and migration are described. Portions of the field are nearly two dimensional, but the overall [...] Read more.
High-resolution bathymetric surveys are interpreted to describe the morphology and movement of a field of sand waves near San Francisco, CA, USA. The sand wave size, shape, orientation, and migration are described. Portions of the field are nearly two dimensional, but the overall field is three dimensional, with changes in sand wave size, orientation, and structure. The trough-to-crest height of individual sand waves ranges from 2 to 9 m. There are a range of wavelengths and orientations. The dominant wavelength ranges from 90 to 100 m, and the orientation clusters around two directions: 40 and 68 degrees. The field is found to be highly dynamic but with stable characteristics over at least decadal timescales. A previously demonstrated paradox between sand wave shape asymmetry and migration direction is revisited using new measurements, showing that reversals in shape asymmetry were accompanied by changes in crest migration direction in one of seven surveys. Full article
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25 pages, 4734 KiB  
Review
Features of the Composition, Release, Localization, and Environmental Effects of Free Gases in the Khibiny Massif (Kola Peninsula, Northwest Russia): A Review
by Valentin A. Nivin
Geosciences 2025, 15(3), 86; https://doi.org/10.3390/geosciences15030086 - 1 Mar 2025
Viewed by 194
Abstract
The article presents a comprehensive analysis of long-term studies on hydrogen-hydrocarbon free gases (FGs) in the rocks of the Khibiny massif, systematically organized and generalized for the first time. Gasometric observations were predominantly conducted within underground mine workings, with occasional measurements taken during [...] Read more.
The article presents a comprehensive analysis of long-term studies on hydrogen-hydrocarbon free gases (FGs) in the rocks of the Khibiny massif, systematically organized and generalized for the first time. Gasometric observations were predominantly conducted within underground mine workings, with occasional measurements taken during the drilling of exploration boreholes at the surface or in subsurface air within loose sediments. Methane is the primary component of these gases, followed in descending order by hydrogen, ethane, helium, other methane homologs, and alkenes. Nitrogen is also presumed to be present, although its proportions remain undefined. The carbon and hydrogen in FGs exhibit relatively heavy isotopic compositions, which progressively lighten from methane to ethane. The intensity of gas emissions is characterized by a gas flow rate from shot holes and boreholes, reaching up to 0.5 L/min but generally decreasing significantly within an hour of reservoir exposure. Gas-bearing areas, ranging in size from a few meters to tens of meters, are distributed irregularly and without discernible patterns. The FG content in rocks and ores varies from trace amounts to approximately 1 m3 of gas per cubic meter of undisturbed rock. These gases are primarily residual, preserved within microfractures and cavities following the isolation of fluid inclusions. Their distribution and composition may fluctuate due to the dynamic geomechanical conditions of the rock mass. The release of flammable and explosive FGs presents a significant hazard during ore deposit exploration and development, necessitating the implementation of rigorous safety measures for mining and drilling operations. Additionally, the environmental implications and potential applications of gas emissions warrant attention. Future comprehensive studies of the Khibiny gases using advanced methodologies and equipment are expected to address various scientific and practical challenges. Full article
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21 pages, 11081 KiB  
Article
High-Resolution Coastal Vulnerability Assessment for the Istrian Peninsula: Developing a Physical Coastal Vulnerability Index (PCVI)
by Zaviša Šimac, Nina Lončar and Sanja Faivre
Geosciences 2025, 15(3), 85; https://doi.org/10.3390/geosciences15030085 - 1 Mar 2025
Viewed by 266
Abstract
Increasing risks from sea-level rise and other climate impacts call for a focus on physical coastal attributes, emphasising the need for region-specific tools to address the vulnerability of different coastlines. This paper presents the development of a Physical Coastal Vulnerability Index (PCVI) for [...] Read more.
Increasing risks from sea-level rise and other climate impacts call for a focus on physical coastal attributes, emphasising the need for region-specific tools to address the vulnerability of different coastlines. This paper presents the development of a Physical Coastal Vulnerability Index (PCVI) for climate change impacts like sea-level rise, erosion, and storm surges, which is applied to the Croatian coast of the Istrian Peninsula. The methodology provides a detailed, site-specific vulnerability assessment focusing on physical parameters such as coastal aspect, slope, elevation, and coastal type. Eight different grid cell sizes were evaluated to map the coastline, demonstrating, as expected, that smaller cells (5 × 5 m) captured more detailed variability in vulnerability. Among seven evaluated calculation methods, the second root of the self-weighted arithmetic mean (M3) proved the most effective, emphasising high-risk regions by prioritising critical physical variables. The results show that the western Istrian coast is more vulnerable due to its morphological properties, with nearly 50% of highly vulnerable coastlines. This paper emphasises the importance of using high-resolution grids to avoid oversimplification of vulnerability assessment and recommends using PCVI as a basis for further socio-economic assessments. The proposed PCVI methodology offers a framework that can be adapted to assess the physical vulnerability of the eastern Adriatic coast and other similar coastal regions, particularly in the Mediterranean, enhancing its relevance for integrated coastal zone management and global climate change mitigation strategies. Full article
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25 pages, 9566 KiB  
Article
Scaling Law Analysis and Aftershock Spatiotemporal Evolution of the Three Strongest Earthquakes in the Ionian Sea During the Period 2014–2019
by Kyriaki Pavlou, Georgios Michas and Filippos Vallianatos
Geosciences 2025, 15(3), 84; https://doi.org/10.3390/geosciences15030084 - 1 Mar 2025
Viewed by 341
Abstract
The observed scaling properties in the three aftershock sequences of the recent strong earthquakes of magnitudes Mw 6.1, Mw 6.4 and Mw 6.7, which occurred in the Ionian island region on the 26 January 2014 (onshore Cephalonia Island), 17 November [...] Read more.
The observed scaling properties in the three aftershock sequences of the recent strong earthquakes of magnitudes Mw 6.1, Mw 6.4 and Mw 6.7, which occurred in the Ionian island region on the 26 January 2014 (onshore Cephalonia Island), 17 November 2015 (Lefkada Island) and 25 October 2018 (offshore Zakynthos Island), respectively, are presented. In the analysis, the frequency–magnitude distributions in terms of the Gutenberg–Richter scaling relationship are studied, along with the temporal evolution of the aftershock sequences, as described by the Omori–Utsu formula. The processing of interevent times distribution, based on non-extensive statistical physics, indicates a system in an anomalous equilibrium with long-range interactions and a cross over behavior from anomalous to normal statistical mechanics for greater interevent times. A discussion of this cross over behavior is given for all aftershock sequences in terms of superstatistics. Moreover, the common value of the Tsallis entropic parameter that was obtained suggests that aftershock sequences are systems with very low degrees of freedom. Finally, a scaling of the migration of the aftershock zones as a function of the logarithm of time is discussed regarding the rate strengthening rheology that governs the evolution of the afterslip process. Our results contribute to the understanding of the spatiotemporal evolution of aftershocks using a first principles approach based on non extensive statistical physics suggesting that this view could describe the process within a universal view. Full article
(This article belongs to the Special Issue Seismic and Aseismic Deformation in the Brittle Crust)
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28 pages, 72675 KiB  
Article
Geochemical and Isotopic Features of Geothermal Fluids Around the Sea of Marmara, NW Turkey
by Francesco Italiano, Heiko Woith, Luca Pizzino, Alessandra Sciarra and Cemil Seyis
Geosciences 2025, 15(3), 83; https://doi.org/10.3390/geosciences15030083 - 1 Mar 2025
Viewed by 302
Abstract
Investigations carried out on 72 fluid samples from 59 sites spread over the area surrounding the Sea of Marmara show that their geochemical and isotopic features are related to different segment settings of the North Anatolian Fault Zone (NAFZ). We collected fluids from [...] Read more.
Investigations carried out on 72 fluid samples from 59 sites spread over the area surrounding the Sea of Marmara show that their geochemical and isotopic features are related to different segment settings of the North Anatolian Fault Zone (NAFZ). We collected fluids from thermal and mineral waters including bubbling and dissolved gases. The outlet temperatures of the collected waters ranged from 14 to 97 °C with no temperature-related geochemical features. The free and dissolved gases are a mixture of shallow and mantle-derived components. The large variety of geochemical features comes from intense gas–water (GWI) and water–rock (WRI) interactions besides other processes occurring at relatively shallow depths. CO2 contents ranging from 0 to 98.1% and helium isotopic ratios from 0.11 to 4.43 Ra indicate contributions, variable from site to site, of mantle-derived volatiles in full agreement with former studies on the NAFZ. We propose that the widespread presence of mantle-derived volatiles cannot be related only to the lithospheric character of the NAFZ branches and magma intrusions have to be considered. Changes in the vertical permeability induced by fault movements and stress accumulation during seismogenesis, however, modify the shallow/deep ratio of the released fluids accordingly, laying the foundations for future monitoring activities. Full article
(This article belongs to the Section Geochemistry)
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