Editor’s Choice Articles

This study aimed to examine the shear strength characteristics of sand–granular rubber mixtures in direct shear tests. Two different sizes of rubber and one of sand were used in the experiment, with the sand being mixed with various percentages of rubber (0%, 10%, 20%, 30%, and 50%). The mixtures were prepared at three different densities (loose, slightly dense, and dense), and shear stress was tested at four normal stresses (30, 55, 105, and 200 kPa). The results of 80 direct shear tests were used to calculate the peak and residual internal friction angles of the mixtures, and it was found that the normal stress had a significant effect on the internal friction angle, with an increase in normal stress leading to a decrease in the internal friction angle. These results indicated that the Mohr–Coulomb theory, which applies to rigid particles only, is not applicable in sand–rubber mixtures, where stiff particles (sand) and soft particles (rubber) are mixed. The shear strength of the mixtures was also influenced by multiple factors, including particle morphology (size ratio, shape, and gradation), mixture density, and normal stress. For the first time in the literature, genetic programming, classification and regression random forests, and multiple linear regression were used to predict the peak and residual internal friction angles. The genetic programming resulted in the creation of two new equations based on mixture unit weight, normal stress, and rubber content. Both artificial intelligence models were found to be capable of accurately predicting the peak and residual internal friction angles of sand–rubber mixtures. Full article

Landmines and explosive remnants of war are still present in the Western Balkans and remain a deadly legacy of the hostilities at the end of the 20th century. Over the years, several incidents have occurred in Bosnia and Herzegovina, in Serbia, and in Croatia where intact ordnance has caused injuries and fatalities. Floods, torrential flows, and gravitational mass movements pose a particular threat. Landmines and explosive remnants of war are mobilized and displaced into previously uncontaminated areas. We first discuss the historical and technical background of this hazardous situation. We then show which hydro-morphological processes are responsible for the mobilization and displacement. We then illustrate how a prediction of the likely contaminated areas can be obtained. We show that the problem can only be tackled using a stochastic-deterministic model. However, for the eventual development of risk-hazard maps, preliminary work using laboratory experiments and field surveys is required. The article, therefore, proposes a novel approach to the problem in an international research project. The aim would be to produce risk-hazard maps that can be used by elected decision-makers, administrative authorities, and emergency personnel in affected municipalities. Full article

Direct shear (DS) is a common geotechnical laboratory test used to determine strength and deformation properties of rock discontinuities, such as normal and shear stiffness, peak and residual shear strength, and dilation. These are used as inputs for discontinuous geomechanical numerical models to simulate discontinuities discretely and shear strength is often expressed by Mohr–Coulomb, Patton, or Barton–Bandis constitutive models. This paper presents a critical review of the different boundary conditions and procedural techniques currently used in practice, summarizes previous contributions, addresses their impacts on interpreted results for rock engineering design, and introduces clarifying terminology for shear strength parameters. Based on the review, the authors advise that constant normal stress is best suited for discrete numerical-model-based rock engineering design in dry conditions, but constant normal stiffness should be considered where fluid permeability is of interest. Multi-stage testing should not be used to obtain peak shear strength values except for stage 1, because of accumulating asperity damage with successive shear stages. Nevertheless, if multi-stage testing must be employed due to limited budget or specimen availability, guidance is presented to improve shear strength results with limited displacement techniques. Full article

Sea caves are a type of cave formed primarily by the wave action of the sea. The coastal scenery of the Gozitan coast is very interesting in that sea caves and other coastal landforms, such as sea arches, develop at the sea level. We mapped seventy-nine semi-submerged sea caves opening at the sea level, five completely submerged sea caves, seven sea arches, one sea stack, and one shelter around the coast of Gozo, mainly in the Western and Eastern parts of the island, due to favorable lithological and topographical conditions. Additionally, we surveyed the topography of the emerged part of nine sea caves using the iPhone build-in LiDAR sensor, and eight sea caves in the submerged part using SCUBA equipment. This inventory represents the most detailed example of a database of coastal caves and related forms in the Mediterranean, mainly sourced from a swimming survey along the entire island. Thanks to the combination of outputs of the above-water emerged and submerged surveys, we defined three types of semi-submerged sea caves: (i) box caves, (ii) joint caves, and (iii) complex caves. Moreover, we added a cave-like landform above the sea level on calcarenites called shelter, or a little extended notch deeply carved into the cliff. The shape mainly depends on the structural and lithological setting of sea cliffs. In the Western sector of the island, we also discovered the only sea cave in Gozo, measuring 122 m in length and 10 m in width, with its floor developing above the mean sea level. This cave base is of interest due to rounded landforms related to marine erosion. In the innermost part of the cave, there is also a beach with rounded pebble at an elevation of about 7 m asl. Considering the tectonic stability of the island, it could be possibly related to the MIS 5.5 highstand. Full article

We present an attempt to estimate the long-term changes in Relative Sea Level (RSL), in addition to the different factors contributing to such trends on a local and regional scale, using a statistical linear model. The time series analysis corresponded to 17 tide-gauges, grouped in three different areas: the northern and western Atlantic coasts of the Iberian Peninsula, the Canary Islands, and the southern and eastern coasts of the Iberian Peninsula and Balearic Islands. The analysis was performed for two periods: 1948–2019, using tide-gauge data; and 1993–2019, using both tide-gauge and altimetry data for comparison. The trends for the period 1948–2019 ranged between 1.09 ± 0.14 (Canary Islands) and 2.05 ± 0.21 mm/yr for the northern and western Atlantic Iberian Peninsula. Altimetry data during the period 1993–2019 yielded quite homogeneous results for all the locations and regions, ranging between 2.7 ± 0.4 and 3.0 ± 0.3 mm/yr. In contrast, the results obtained from tide-gauge data for this recent period showed a large dispersion, very likely due to local effects, or perhaps even to levelling or instrumental errors. Nevertheless, when the results were averaged for each area, the observed trends were comparable to the altimetry results, with values of 2.3 ± 0.8, 2.7 ± 0.5, and 2.8 ± 0.8 mm/yr for the three regions of study. A stepwise forward linear regression was used to relate the observed RSL variability to the atmospheric forcing and the thermosteric and halosteric components of the sea level. Surprisingly, the thermosteric and halosteric contributions were not significantly correlated to the observed RSL in many cases; consequently, the steric, the total addition of mass, the mass of salt, and the freshwater contributions to the observed sea level trends could not be reliably estimated. This result seems to have been the consequence of the scarcity of temperature and salinity data; this hypothesis was confirmed, with the exception of the tide-gauge data for L’Estartit. This location is close to a well sampled region. In this case, the atmospheric variables and the thermosteric and halosteric terms accounted for 80% of the observed RSL variance, and the contributions of these terms could be estimated. The freshwater contribution for this location was between 1.3 and 1.4 mm/yr, consistent with recent estimations of the contributions of glaciers and Greenland and Antarctica Ice Sheets. These results highlight the importance of monitoring programs and routine sampling for the determination of the different factors contributing to the sea level variability. Full article

The geosites of Lemnos represent local touristic products that, beyond their high aesthetic value, display significant scientific links to the geological past as well as prehistory and history, archaeology, mythology and religious heritage of the island. The unique wealth of Lemnos geosites in combination with the abundance of archaeological sites, cultural monuments and museums composes the basis of what we define here as “Geo-Archaeo-Routes”: certain routes that can be geographically defined, offered, guided and finally followed by the touristic masses. The outcome of the performed quantitative Lemnos geosite assessment enables decision making, thus providing a toolbox useful for sustainable Geo-Archaeo-tourism development at a local level and forms the basis for designing “Geo-Archaeo-Routes”. “Geo-Archaeo-Routes” are particularly favorable of environmentally friendly alternative types of tourism, attracting naturalists, hikers, fans of cultural or religious tourism and many others who represent a major part of the touristic needs of the 21st century. The established hiking and road “Geo-Archaeo-Routes” on Lemnos Island may represent a distinctive touristic product as they offer a high level of “nalture” entertainment, blending “nature with culture” in the framework of a holistic geotouristic approach. Full article

In recent years, an international consortium of research organizations conducted investigations at the Chicxulub Crater in Yucatan, Mexico, to better understand the crater’s formation mechanisms and the effects produced by the impact of the asteroid that is hypothesized to have caused one of the major life extinctions on Earth. This study aims to reproduce the asteroid’s impact mechanics by matching computer simulations obtained with the use of the distinct element method (DEM) against the latest topographic data observed across the crater footprint. A 2D model was formulated using ITASCA’s PFC2D software to reproduce the asteroid’s impact on Earth. The model ground conditions prior to impact were replicated based on available geological and geophysical field information. Also, the proposed DEM model configuration was designed to reproduce a far-field effect to ascertain the energy dissipation of the asteroid’s impact at the model’s boundaries. Impact conditions of the asteroid were defined based on previous asteroid impact investigations. A parametric analysis including the asteroid’s impact angle and the asteroid’s impact velocity was conducted to assess their influence on the crater formation process. Results of the simulations included the final crater topography and stratigraphy, stress profiles, contact force chains, and velocity fields. Numerical simulations showed that both the asteroid velocity and impact inclination play a major role in the crater formation process, and that the use of DEM provides interesting insights into impact crater formation. Full article

Flood warning and response systems are essential components of risk reduction strategies with the potential to reduce loss of life and impact on personal assets. However, recent flood incidents have caused significant loss of human lives due to failures in current flood warning and response mechanisms. These failures are broadly related to policies concerning, and governance aspects within, warning generation, the behaviour of communities in responding to early warnings, and weaknesses in associated tools and technologies used in communicating early warnings and responding. Capturing critical failure factors affecting flood warning and response systems can provide opportunities for making corrective measures and for developing a more advanced and futuristic system for early flood warnings. This paper reports the findings of a structured review that was conducted to identify critical failure factors in flood early warning and response systems. This study found twenty-four critical failure factors (CFFs). The interpretive structural modelling (ISM) approach conducted in this study resulted in identifying four different types of failure factors (autonomous, dependent, linkage, and independent) with varying dependence and driving powers. Analysis shows that governance, leadership, finance, standard operating procedures (SoP), and community engagement are the most dominating factors with the highest driving factor, which can overcome other dependent factors. The outcome of this review could be helpful for policymakers and practitioners in overcoming failure factors and implementing effective early warning and response systems. Full article

At the end of November 2021, a large area of Puglia (an administrative region in Southern Italy) was officially nominated as new aUGGp (aspiring UNESCO Global Geopark) by the Italian National Commission of UNESCO. This area comprises the northwestern part of the Murge territory, where a Cretaceous sector of the Apulia Carbonate Platform crops out, and part of the adjacent Premurge territory, where the southwestward lateral continuation of the same platform (being flexed toward the Southern Apennines Chain) is covered by thin Plio-Quaternary foredeep deposits. The worldwide geological uniqueness of the aspiring Geopark (Murge aUGGp) is that the area is the only in situ remnant of the Adria Plate, the old continental plate almost entirely squeezed between the Africa and Eurasia Plates. In such a context, the Murge area (part of the Apulia Foreland) is a virtually undeformed sector of Adria, while other territories of the plate are and/or were involved in the subduction/collision processes. In the aspiring Geopark, the crust of Adria is still rooted to its mantle, and the Cretaceous evolution of the continent is widely recorded in the Murge area thanks to the shallow-water carbonate succession of one of the largest peri-Tethys carbonate platforms (the Apulia Carbonate Platform). The aspiring Geopark also comprises the Premurge area, which represents the outer Southern Apennines foredeep, whose Plio-Quaternary evolution is spectacularly exposed thanks to an “anomalous” regional middle-late Quaternary uplift. Despite the presence of numerous geological singularities of international importance, it would be important, from a geotourist point of view, to propose a regional framework of the geology of the aUGGp before introducing visitors to the significance of the individual geosites, whose importance could be amplified if included in the geoevolutionary context of the Murge aUGGp. Full article

The rigorous assessment of volcanic hazards relies on setting contemporary monitoring observations within an accurate, longer-term geological context. Revealing that geological context requires the detailed fieldwork, mapping and laboratory analysis of the erupted materials. However, many of the world’s most dangerous volcanic systems are located on or near coasts (e.g., the Phlegraean Fields and Vesuvius in Italy), islands (e.g., the volcanic archipelagos of the Pacific, south-east Asia, and Eastern Caribbean), or underwater (e.g., the recently erupting Hunga Tonga–Hunga Ha’apai volcano), meaning that much of their erupted material is deposited on the sea bed. The only way to sample this material directly is with seafloor sediment cores. This perspectives paper outlines how marine sediment cores are a vital yet underused resource for assessing volcanic hazards by: (1) outlining the spatio-temporal scope of the marine volcanic record and its main deposit types, (2) providing existing examples where marine sediments have contributed to volcanic hazard assessments; (3) highlighting the Sunda Arc, Indonesia as an example location where marine sediment cores are yet to contribute to hazard assessments, and (4) proposing that marine sediment cores can contribute to our understanding of very large eruptions that have a global impact. Overall, this perspectives paper aims to promote the utility of marine sediment cores in future volcanic hazard assessments, while also providing some basic information to assist researchers who are considering integrating marine sediment cores into their volcanological research. Full article

Rock glaciers are an integral part of the periglacial environment. At the regional scale in the Greater Caucasus, there have been no comprehensive systematic efforts to assess the distribution of rock glaciers, although some individual parts of ranges have been mapped before. In this study we produce the first inventory of rock glaciers from the entire Greater Caucasus region—Russia, Georgia, and Azerbaijan. A remote sensing survey was conducted using Geo-Information System (GIS) and Google Earth Pro software based on high-resolution satellite imagery—SPOT, Worldview, QuickBird, and IKONOS, based on data obtained during the period 2004–2021. Sentinel-2 imagery from the year 2020 was also used as a supplementary source. The ASTER GDEM (2011) was used to determine location, elevation, and slope for all rock glaciers. Using a manual approach to digitize rock glaciers, we discovered that the mountain range contains 1461 rock glaciers with a total area of 297.8 ± 23.0 km². Visual inspection of the morphology suggests that 1018 rock glaciers with a total area of 199.6 ± 15.9 km² (67% of the total rock glacier area) are active, while the remaining rock glaciers appear to be relict. The average maximum altitude of all rock glaciers is found at 3152 ± 96 m above sea level (a.s.l.) while the mean and minimum altitude are 3009 ± 91 m and 2882 ± 87 m a.s.l., respectively. We find that the average minimum altitude of active rock glaciers is higher (2955 ± 98 m a.s.l.) than in relict rock glaciers (2716 ± 83 m a.s.l.). No clear difference is discernible between the surface slope of active (41.4 ± 3°) and relict (38.8 ± 4°) rock glaciers in the entire mountain region. This inventory provides a database for understanding the extent of permafrost in the Greater Caucasus and is an important basis for further research of geomorphology and palaeoglaciology in this region. The inventory will be submitted to the Global Land Ice Measurements from Space (GLIMS) database and can be used for future studies. Full article

The present work is aimed at assessing the change in time of flood risk as a consequence of landscape modifications. The town of San Donà di Piave (Italy) is taken as a representative case study because, as most parts of the North Italy floodplains, it was strongly urbanized and anthropized in the last several decades. As a proxy for flood risk, we use flood damage to residential buildings. The analysis is carried out at the local scale, accounting for changes to single buildings; GIS data such as high-resolution topography, technical maps, and aerial images taken over time are used to track how the landscape evolves over time, both in terms of urbanized areas and of hydraulically relevant structures (e.g., embankments). Flood hazard is determined using a physics-based, finite element hydrodynamic code that models in a coupled way the flood routing within the Piave River, the formation of levee failures, and the flooding of adjacent areas. The expected flood damage to residential buildings is estimated using an innovative method, recently proposed in the literature, which allows estimating how the damage evolves during a single flood event. The decade-scale change in the expected flood damage reveals the detrimental effect of urbanization, with flood risk growing at the pace of a fraction of urbanized areas. The within-event time evolution of the flood damage, i.e., how it progresses in the course of past or recent flood events, reflects changes in the hydrodynamic process of flooding. The general methodology used in the present work can be viewed as a promising technique to analyze the effects on the flood risk of past landscape evolution and, more importantly, a valuable tool toward an improved, well-informed, and sustainable land planning. Full article

In this work, the shallow geothermal heat-exchange potential of a coastal plain in southern Italy, the Sant’Eufemia plain (Calabria region), was evaluated. Stratigraphic and hydrogeological data and thermophysical properties of the main geological formations of the area have been averaged over the first 100 m of subsoil to define the thermal conductivity, the specific heat extraction rates of the ground and the geothermal potential of the area (MWh·y⁻¹) for both cooling and heating modes. The investigation revealed that the crystalline bedrock and the saturated conditions of the sedimentary infill mainly control the heat-exchange potential. The range of the geothermal potential in the investigated Sant’Eufemia plain is 3.61–10.56 MWh·y⁻¹ and 3.72–11.47 MWh·y⁻¹ for heating and cooling purposes, respectively. The average depth drilled to supply a standard domestic power demand of 5.0 kW is ~90 m for heating and ~81 m for cooling modes. The different depth also drives the final drilling costs, which range from EUR 3200 to 8700 for the heating mode and from EUR 2800 to 7800 for the cooling mode. Finally, the mean values of drilling depth and costs for both heating and cooling modes are provided for the main municipalities and strategic sites. Full article

Natural hydrogen is known to be generated in the crust by water/rock interactions, especially the oxidation of iron-rich rock or radiolysis. However, other sources, especially deeper ones, exist. In the context of subduction, the dehydration of the slab, the destabilization of the NH₄, and the hydration of the mantle wedge above the subducting lithosphere may generate H₂. We present here a compilation of the known gases in the central part of the Pacific subduction and the results of a first field acquisition dedicated to H₂ measurements in Bolivia between La Paz and South Lipez. Various zones have been studied: the emerging thrust faults of the western borders of the Eastern Cordillera, the Sajama area that corresponds to the western volcanic zone near the Chile border northward from the Uyuni Salar, and finally, the Altiplano-Puna Volcanic Complex in South Lipez. Soil gas measurement within and around the Salar itself was not fully conclusive. North of the Uyuni Salar, the gases are very rich in CO₂, enriched in N₂ and poor in H₂. On the opposite, southward, all the samples contain some H₂; the major gas is nitrogen, which may overpass 90% after air correction, and the CO₂ content is very limited. On the western border of the Cordillera, the δC13 isotope varies between −5 and −13‰_, and it is not surprisingly compatible with volcanic gas, as well as with asthenospheric CO₂. The methane content is close to 0, and only a few points reach 1%. The isotopes (−1‰) indicate an abiotic origin, and it is thus related to deep H₂ presence. The high steam flow in the geothermal area of South Lipez combined with the H₂ content in the water results in at least 1 ton of H₂ currently released per day from each well and may deserve an evaluation of its economic value. The nitrogen content, as in other subduction or paleo-subduction areas, questions the slab alteration. Full article

An 8th century CE earthquake severely damaged inland cities across the southern-central Levant, but reported evidence of this earthquake along the coastline is scarce. In Caesarea Maritima, archaeologists have found contemporaneous anomalous sand and shelly layers within nearshore structures and interpreted them as construction fill, aeolian accumulation, or abandonment debris. Recently, similar sand deposits were exposed in a Roman-to-Islamic harbor-side warehouse. This presented the first opportunity to directly sample and systematically analyze in situ, undisturbed deposits in order to determine their origin and taphonomic (source and transport) history. Two sediment cores from the deposit as well as comparative reference samples from defined contexts were analyzed for grain size distribution, foraminifera (abundance/taphonomy), and relative age (POSL, archaeochronology). The results support the interpretation that the deposit was formed from the transport of offshore marine sediments during a high-energy inundation event, most likely a tsunami associated with the 749 CE earthquake. Full article

Porphyry deposits are the dominant sources of copper and major sources of several base and precious metals. They are commonly formed via the repeated emplacement of hydrous magmas and associated fluid exsolution. As a result, mineralized hydrothermal veins may undergo multiple deposition and reopening processes that are not fully accounted for by existing fluid models. The Tongchang porphyry Cu deposit is a rare example of being related to a single intrusion. The simplicity in intrusive history provides an ideal starting point for studying fluid processes in more complex multi-intrusion porphyry systems. Detailed scanning electron microscope (SEM) cathodoluminescence imaging (CL) revealed rich microtextures in quartz and anhydrite that point to a fluid timeline encompassing early quartz deposition followed by fluid-aided dynamic recrystallization, which was succeeded by an intermediate stage of quartz dissolution and subsequent deposition, and ended with a late stage of continuous quartz deposition, brecciation, and fracturing. Vein reopening is more common than expected. Fifteen out of seventeen examined vein samples contained quartz and/or anhydrite that was older or younger than the vein age defined by vein sequences. Thermobarometry and solubility analysis suggests that the fluid events occurred in a general cooling path (from 650 °C to 250 °C), interspersed with two episodes of fluid pressurization. The first episode occurred at high-T (>500 °C), under lithostatic conditions alongside dynamic recrystallization, whereas the second one took place at a lower temperature (~400 °C), under lithostatic to hydrostatic transition conditions. The main episode of chalcopyrite veining took place subsequent to the second overpressure episode at temperatures of 380–300 °C. The results of this study reaffirm that thermal and hydraulic conditions are the main causative factors for vein reopening and growth in porphyry deposits. Full article

Teaching geology under COVID-19 pandemic conditions led to teaching limitations for educators and learning difficulties for students. The lockdown obstructed face-to-face teaching, laboratory work, and fieldtrips. To minimize the impact of this situation, new distance learning teaching methods and tools were developed. The current study presents the results of an empirical study, where distance learning teaching tools were constructed and used to teach geology to university students. A mineralogical mobile phone application was used to replace laboratory mineral identification and a flow chart to replace laboratory rock identification. Additionally, exercises on faults and maps were developed to fill the gap that was created as field work was impossible. A university course on geology was designed on the basis of the constructed distance learning teaching tools, and more than 100 students from the Department of Civil Engineering attended the course. The results show that the proposed tools helped the students to considerably understand scientific information on geology and supported the learning outcomes. Thus, it is suggested that the teaching tools, constructed for the purposes of the study, could be used in conditions when distance learning is required, or even under typical learning conditions after laboratories, as well as before or after fieldtrips, for better learning outcomes. Full article

In tunnel excavation with boring machines, the tunnel face is supported to avoid collapse and minimise settlement. This article proposes the use of reinforcement learning, specifically the deep Q-network algorithm, to predict the face support pressure. The algorithm uses a neural network to make decisions based on the expected rewards of each action. The approach is tested both analytically and numerically. By using the soil properties ahead of the tunnel face and the overburden depth as the input, the algorithm is capable of predicting the optimal tunnel face support pressure whilst minimising settlement, and adapting to changes in geological and geometrical conditions. The algorithm reaches maximum performance after 400 training episodes and can be used for random geological settings without retraining. Full article

Nisyros Geopark, an island geopark in the Southeastern Aegean Sea, Greece, is here presented as an official candidate for the UNESCO Global Geoparks designation, featuring outstanding geological, natural and cultural characteristics tightly connected to its volcanic origin. It covers a total area of 481 km² and includes Nisyros, an active volcano and the main island, the surrounding islets of Pachia, Strongyli, Pergousa, Kandeliousa and the marine region among them. It features 24 geosites and a network of well-established walking trails. Furthermore, there are two internationally designated Natura 2000 areas covering its entire surface and also exceptional archaeological and cultural sites, including fortresses, remnants of ancient habituations and numerous churches and monasteries. It is the only area in the broader region of the Eastern Mediterranean that hosts all these features within such a restricted area. The initial efforts of the management body of Nisyros Geopark and its scientific team to promote its unique geodiversity included the complete design, construction and launch of the official website, the mobile application “Nisyros Volcano App’’, a modern informative leaflet regarding the region of the hydrothermal craters (Lakki), a Geopark guidebook and a series of panels and signs for the geosites. Full article

The Caribbean region is highly vulnerable to multiple hazards. Resultant impacts may be derived from single or multiple cascading risks caused by hydrological-meteorological, seismic, geologic, or anthropological triggers, disturbances, or events. Studies suggest that event records and data related to hazards, risk, damage, and loss are limited in this region. National Disaster Risk Reduction (DRR) planning and response require data of sufficient quantity and quality to generate actionable information, statistical inferences, and insights to guide continual policy improvements for effective DRR, national preparedness, and response in both time and space. To address this knowledge gap, we review the current state of knowledge, data, models, and tools, identifying potential opportunities, capacity needs, and long-term benefits for integrating Earth Observation (EO) understanding, data, models, and tools to further enhance and strengthen the national DRR framework using two common disasters in Jamaica: floods and landslides. This review serves as an analysis of the current state of DRR management and assess future opportunities. Equally, to illustrate and guide other United Nations Disaster Risk Reduction (UNDRR) priority countries in the Pacific region, known as Small Island Developing States (SIDS), to grapple with threats of multiple and compounding hazards in the face of increasing frequency, intensity, and duration of extreme weather events, and climate change impact. Full article

Shoreline change and coastal erosion resulting from natural events such as sea level rise and negative anthropogenic activities continue to be problems in many of the world’s coastal regions. Many coastal socio-ecological systems have become vulnerable as a result, especially in developing countries with less adaptive capacity. We utilized the systematic method to understand the research progress and policy recommendations on shoreline change and coastal erosion in West Africa. A total of 113 documents were retrieved from Scopus and the Web of Sciences databases, and 43 documents were eligible following established criteria. It was revealed that research on shoreline change and coastal erosion has progressed substantially since 1998, with most research studies originating from the Ghanaian territory. Again, most of the shoreline change and erosion problems in West Africa result from natural events such as sea level rise. However, there was evidence of anthropogenic influences such as sand mining, dam construction, and human encroachment causing shoreline change and erosion in the region. Research in the region has also progressed in terms of methodological approaches. Since 2004, researchers have utilized remote sensing and GIS techniques to source and analyze shoreline change and erosion. However, a combination of remote sensing and field observation approaches is required to clearly depict the erosion problems and aid policy direction. The overall call to action regarding policy recommendations revolves around improving coastal adaptation measures and the resilience of communities, instituting proper coastal zone management plans, and improving shoreline change and coastal erosion research. To protect lives and property, policymakers in the region need to set up good coastal zone management plans, strengthen adaptation measures, and make coastal communities more resistant to possible risks. Full article

The stability and kinematics of rock slopes are widely considered to be functions of lithological, structural, and environmental features. Conversely, slope damage features are often overlooked and considered as byproducts of slope deformation. This paper analyzes and discusses the potential role of slope damage, its time-dependent nature, and its control on both the stability of rock slopes and their kinematics. The analysis of several major landslides and unstable slopes, combined with a literature survey, shows that slope damage can play an important role in controlling short- and long-term slope stability. Seasonal and continuously active events cause permanent deformation within the slope due to the accumulation of slope damage features, including rock mass dilation and intact rock fracturing. Rock mass quality, lithology, and scale control the characteristics and complexity of slope damage, as well as the failure mechanism. The authors propose that the role of slope damage in slope kinematics should always be considered in slope stability analysis, and that an integrated characterization–monitoring–numerical modelling approach can enhance our understanding of slope damage, its evolution, and the controlling factors. Finally, it is emphasized that there is currently a lack of guidelines or frameworks for the quantitative assessment and classification of slope damage, which requires a multidisciplinary approach combining rock mechanics, geomorphology, engineering geology, remote sensing, and geophysics. Full article

Landslide impact is potentially hazardous to an urban environment. Landslides occur at certain slope levels over time and require practical slope analysis to assess the nature of the slope where a landslide is likely to occur. Thus, acquiring very high-resolution remote sensing data plays a significant role in determining the slope surface. For this study, 12 landslide conditioning parameters with 10 × 10 cell sizes that have never been previously collectively applied were created. These factors were created directly from the LiDAR (Light Detection and Ranging) DEM (digital elevation model)using their layer toolboxes, which include slope, aspect, elevation, curvature, and hill shade. Stream power index (SPI), topographic wetness index (TWI), and terrain roughness index (TRI) were created from spatial layers such as slope, flow direction, and flow accumulation. Shapefiles of distances to roads, lakes, trees, and build-up were digitized as land use/cover from the LiDAR image and produced using the Euclidean distance method in ArcGIS. The parameters were selected based on expert knowledge, previous landslide literature, and the study area characteristics. Moreover, multicriteria decision-making analysis, which includes the analytic hierarchy process (AHP) and fuzzy logic approaches not previously utilized with a LiDAR DEM, was used in this study to predict the possibility of a landslide. The receiver operating characteristics (ROC) were used for the validation of results. The area under the curve (AUC) values obtained from the ROC method for the AHP and fuzzy were 0.859 and 0.802, respectively. The final susceptibility results will be helpful to urban developers in Malaysia and for sustainable landslide hazard mitigation. Full article

The Early Cretaceous Yellow Cat Member of the terrestrial Cedar Mountain Formation in Utah, USA. has been interpreted as a “time-rich” unit because of its dinosaur fossils, prominent paleosols, and the results of preliminary chemostratigraphic and geochronologic studies. Herein, we refine prior interpretations with: (1) a new composite C-isotope chemostratigraphic profile from the well-known Utahraptor Ridge dinosaur site, which exhibits δ¹³C features tentatively interpreted as the Valanginian double-peak carbon isotope excursion (the so-called “Weissert Event”) and some unnamed Berriasian features; and (2) a new cryptotephra zircon eruption age of 135.10 ± 0.30/0.31/0.34 Ma (2σ) derived from the CA-ID-TIMS U-Pb analyses of zircons from a paleosol cryptotephra. Our interpretations of δ¹³C features on our chemostratigraphic profile, in the context of our new radiometric age, are compatible with at least one prior age model for the “Weissert Event” and the most recent revision of the Cretaceous time scale. Our results also support the interpretation that the Yellow Cat Member records a significant part of Early Cretaceous time. Full article

The impacts of Climate Change are quite visible in Guinea-Bissau. Greater irregularity at the beginning and end of the rainy season, as well as in relation to the interannual variability of precipitation, are evidence that shows these phenomena in West African countries and particularly in Guinea-Bissau, where the agriculture is rain-fed. The year 2020 was characterized as very rainy in comparison to the climatological average of 1981–2020, with positive anomalies throughout the country, despite the late arrival of the wet season, which usually occurs in May. July, August, and September 2020 were the rainiest months, registering above a normal frequency of days with precipitation greater than 50 mm. Bissau, the capital, registered a record-breaking annual rainfall and monthly amounts higher than the 90th and 95th percentiles in July and August, respectively. This heavy rain accompanied by strong winds caused flooding in several urban areas and agricultural fields, and the destruction of roads, houses, and infrastructures in different cities across the country. As a way of mitigating these impacts, the government, through the Ministry of Solidarity, made available 100 million CFA francs (6.5 million euros) to help families that were victims of the floods. Full article

In this paper, the 1978–2022 series of northern (NHSI) and southern (SHSI) hemisphere sea ice extent are submitted to singular spectral analysis (SSA). The trends are quasi-linear, decreasing for NHSI (by 58,300 km${}^2$/yr) and increasing for SHSI (by 15,400 km${}^2$/yr). The amplitude of annual variation in the Antarctic is double that in the Arctic. The semi-annual components are in quadrature. The first three oscillatory components of both NHSI and SHSI, at 1, 1/2, and 1/3 yr, account for more than 95% of the signal variance. The trends are respectively 21 (Antarctic) and 4 times (Arctic) less than the amplitudes of the annual components. We next analyze variations in pole position (PM for polar motion, coordinates $m_1$, $m_2$) and length of day (lod). Whereas the SSA of the lod is dominated by the same first three components as sea ice, the SSA of the PM contains only the 1-yr forced annual oscillation and the Chandler 1.2-yr component. The 1-yr component of NHSI is in phase with that of the lod and in phase opposition with m₁, while the reverse holds for the 1-yr component of SHSI. The semi-annual component appears in the lod and not in $m_1$. The annual and semi-annual components of NHSI and SHSI are much larger than the trends, leading us to hypothesize that a geophysical or astronomical forcing might be preferable to the generally accepted forcing factors. The lack of modulation of the largest (SHSI) forced component does suggest an alternate mechanism. In Laplace’s theory of gravitation, the torques exerted by the Moon, Sun, and planets play the leading role as the source of forcing (modulation), leading to changes in the inclination of the Earth’s rotation axis and transferring stresses to the Earth’s envelopes. Laplace assumes that all masses on and in the Earth are set in motion by astronomical forces; more than variations in eccentricity, it is variations in the inclination of the rotation axis that lead to the large annual components of melting and re-freezing of sea-ice. Full article

Circular landscape features, including kettle lakes, sinkholes, pingos, calderas, and craters, develop from a variety of different geomorphic processes on Earth. On many rocky extraterrestrial surfaces, including Mars, the most common circular landscape features are craters, and the density of these craters is commonly used to estimate the age of the surface. On planetary bodies where fluvial, volcanic, and glacial geomorphic processes are not present, alternative interpretations of circular features can safely be ignored. However, Mars once hosted an Earth-like climate and many elements of the Martian landscape that are visible today were formed by ancient fluvial, glacial, or volcanic processes. In this work, we focus on the potential presence of postglacial kettle hole depressions on Mars. We explore the size and density distribution of kettle lakes in three analog postglacial landscapes on Earth and discuss the implications for planetary surface age dating if kettles and craters are present together in the landscape on Mars. Full article

Lefkada and Corfu old towns are located in the western part of Greece, in the Ionian Sea. Their proximity to the Hellenic subduction zone (HSZ) is the reason for their intense seismicity. The main goal of this study was the estimation of the geotechnical characteristics of the subsurface, with the contribution of applied geophysical techniques. Therefore, seismic refraction tomography (SRT) and multichannel analysis of surface waves (MASW) were applied. A total of thirty-three (33) seismic and geoelectrical profiles were performed in both towns in order to evaluate the geotechnical characteristics of the subsurface formations. Additionally, subsurface resistivity distributions were investigated with the application of electrical resistivity tomography (ERT). Some important elastic moduli were calculated through the combination of estimated seismic wave velocities and laboratory density measurements. The horizontal distribution of seismic velocities and mechanical properties (σ, E, K, G) of Corfu town was illustrated in maps, for the depth of 5 m. The geophysical interpretation also revealed that Lefkada’s subsurface consists of only one compact geological formation, with little or no variation of its geophysical-geotechnical characteristics. Beyond that, the ground type classifications for the two towns were determined according to the European Committee for Standardization Eurocode 8, based on V_S30 values. Full article

With the recent push for a transition towards a climate-resilient economy, the demand on marine resources is accelerating. For many economic exploits, a comprehensive understanding of environmental parameters underpinning seabed morphodynamics in tidally-dominated shelf seas, and the relationship between local and regional scale sediment transport regimes as an entire system, is imperative. In this paper, high-resolution, time-lapse bathymetry datasets, hydrodynamic numerical modelling outputs and various theoretical parameters are used to describe the morphological characteristics of sediment waves and their spatio-temporal evolution in a hydrodynamically and morphodynamically complex region of the Irish Sea. Analysis reveals sediment waves in a range of sizes (height = 0.1 to 25.7 m, and wavelength = 17 to 983 m), occurring in water depths of 8.2 to 83 mLAT, and migrating at a rate of 1.1 to 79 m/yr. Combined with numerical modelling outputs, a strong divergence of sediment transport pathways from the previously understood predominantly southward flow in the south Irish Sea is revealed, both at offshore sand banks and independent sediment wave assemblages. This evidence supports the presence of a semi-closed circulatory hydrodynamic and sediment transport system at Arklow Bank (an open-shelf linear sand bank). Contrastingly, the Lucifer–Blackwater Bank complex and associated sediment waves are heavily influenced by the interaction between a dominant southward flow and a residual headland eddy, which also exerts a strong influence on the adjacent banner bank. Furthermore, a new sediment transfer system is defined for offshore independent sediment wave assemblages, whereby each sediment wave field is supported by circulatory residual current cells originating from offshore sand banks. These new data and results improve knowledge of seabed morphodynamics in tidally-dominated shelf seas, which has direct implications for offshore renewable developments and long-term marine spatial planning. Full article

In the past decade, there has been an increasing trend of digitalizing rock engineering processes. However, this process has not been accompanied by a critical analysis of the very same empirical methods that many complex numerical and digital methods are founded upon. As engineers, we are taught to use and trust numbers. Indeed, we would not be able to define the factor of the safety of a structure without numbers. However, what happens when those numbers are nothing but numerical descriptions of qualitative assessments? In this paper we present a critical review of the many attempts presented in the literature to quantify GSI (geological strength index). To the authors’ knowledge, this paper represents the first time that all the different GSI tables and quantification methods that have been proposed over the past two decades are collated and compared critically. In our critique, we argue against the paradigm whereby the quantification process adds the experience factor for inexperienced engineers. Furthermore, we discuss the limitations of the notion that GSI quantification methods could transform subjectivity into objectivity since the parameters under considerations are not quantitative measurements. Relying on empirically defined quantitative equivalences raises important questions, particularly when these quantitative equivalences are being used to define so-called accurate rock mass classification input for design purposes. Full article

Globally, coastal zones, rivers and riverine areas, and deltas carry enormous values for ecosystems, socio-economic, and environmental perspectives. These often highly populated areas are generally significantly different from interior hinterlands in terms of population density, economic activities, and geophysical and ecological processes. Geospatial technologies are widely used by scholars from multiple disciplines to understand the dynamic nature of shoreline changes globally. In this paper, we conduct a systematic literature review to identify and interpret research patterns and themes related to shoreline change detection from 2000 to 2021. Two databases, Web of Science and Scopus, were used to identify articles that investigate shoreline change analysis using geospatial technique such as remote sensing and GIS analysis capabilities (e.g., the Digital Shoreline Analysis System (DSAS). Between the years 2000 and 2021, we initially found 1622 articles, which were inspected for suitability, leading to a final set of 905 articles for bibliometric analysis. For systematic analysis, we used Rayyan—a web-based platform used for screening literature. For bibliometric network analysis, we used the CiteSpace, Rayyan, and VOSviewer software. The findings of this study indicate that the majority of the literature originated in the USA, followed by India. Given the importance of protecting the communities living in the riverine areas, coastal zones, and delta regions, it is necessary to ask new research questions and apply cutting-edge tools and technology, such as machine learning approach and GeoAI, to fill the research gaps on shoreline change analysis. Such approaches could include, but are not limited to, centimeter level accuracy with high-resolution satellite imagery, the use of unmanned aerial vehicles (UAV), and point cloud data for both local and global level shoreline change and analysis. Full article

Differences in formulation of the equations of celestial mechanics may result in differences in interpretation. This paper focuses on the Liouville-Euler system of differential equations as first discussed by Laplace. In the “modern” textbook presentation of the equations, variations in polar motion and in length of day are decoupled. Their source terms are assumed to result from redistribution of masses and torques linked to Earth elasticity, large earthquakes, or external forcing by the fluid envelopes. In the “classical” presentation, polar motion is governed by the inclination of Earth’s rotation pole and the derivative of its declination (close to length of day, lod). The duration and modulation of oscillatory components such as the Chandler wobble is accounted for by variations in polar inclination. The “classical” approach also implies that there should be a strong link between the rotations and the torques exerted by the planets of the solar system. Indeed there is, such as the remarkable agreement between the sum of forces exerted by the four Jovian planets and components of Earth’s polar motion. Singular Spectral Analysis of lod (using more than 50 years of data) finds nine components, all with physical sense: first comes a “trend”, then oscillations with periods of ∼80 yrs (Gleissberg cycle), 18.6 yrs, 11 yrs (Schwabe), 1 year and 0.5 yr (Earth revolution and first harmonic), 27.54 days, 13.66 days, 13.63 days and 9.13 days (Moon synodic period and harmonics). Components with luni-solar periods account for 95% of the total variance of the lod. We believe there is value in following Laplace’s approach: it leads to the suggestion that all the oscillatory components with extraterrestrial periods (whose origin could be found in the planetary and solar torques), should be present in the series of sunspots and indeed, they are. Full article

Studies on earthquakes that occurred in the early instrumental period of seismology are of importance for the seismic hazard assessment and are still under investigation since new data are being increasingly revealed. We study the case of a moderate-to-strong earthquake that occurred on 15 July 1909 in NW Peloponnese, Greece. Although the earthquake event was quite destructive, it remains little-known so far in the seismological tradition. We compiled a variety of documentary sources and showed that the earthquake caused extensive building destruction in Chavari and in many other villages with an estimated maximum intensity IX (in EMS-98 scale) and a death toll as high as 55. We also assigned macroseismic intensities in several observation points and drew isoseismal lines by applying the nearest-neighbor technique. From empirical relationships between magnitude and intensities, we estimated the macroseismic magnitude of proxy M_s5.9. Our examination also revealed a variety of earthquake associated phenomena including several types of precursors and abundant co-seismic hydrological changes and ground failures, such as soil liquefaction, surface ruptures, and rock falls. Since no surface fault-trace was reported, the determination of the causative blind fault remains an open issue for future investigation. Full article

Coastal embankments often collapse due to the tremendous destructive energy of an overtopping tsunami flow due to a deep scour by nappe flow. Hence, to clarify the nappe flow formation condition due to the overtopping, a series of tests were carried out within a laboratory flume with immobile settings by lowering the downstream surface angle of an embankment model while keeping the upstream surface slope constant (1:1) with five non-dimensional overtopping depths and six different crest conditions. The conditions imposed on the embankment crest in the flow direction were without vegetation; horizontal crest, (−)4% descending crest slope, (+)4% ascending crest slope, and adding vegetation model with three different densities across the horizontal crest to improve resistance to the flow. The increased resistance provided by the vegetation models were categorized based on the spacing ratio between cylinders to diameter: sparse, intermediate, and dense. Increased vegetation density above the crest results in a significant reduction of flow energy by approximately 30–50% at the downstream brink edge and 40–60% at the downstream plunge basin. In contrast, the maximum energy reduction was found to be by the dense vegetation model. Additionally, owing to the steep slope of the water surface profile and the increasing vegetation density, the impinging jet’s impact point moved closer to the toe of an embankment. This implies that vegetation covers a smaller area while increasing density to mitigate the destructive intensity of flood/tsunami movement. Meanwhile, the descending crest scenario results in a faster nappe flow formation. In contrast, the ascending crest scenario delays the nappe formation while reducing the downstream slope angle. It maintains the sub-critical flow at the crest, except near the downstream brink edge. Full article

Mining activities promote resulting wastes, so coal mines are prone to release contaminants to the environment, namely to the soil and water. Therefore, the analysis of this type of risk is crucial in waste pile management. The São Pedro da Cova (Porto, Portugal) coal waste pile has been studied in recent years, with several data acquired from 2019–2021 under a research project using distinct methodologies. These results are now combined in a multi-approach method to estimate the environmental impacts of the waste pile and identify the contamination. With the integration of all the data in a Geographical Information System (GIS) environment, and to fulfill a scientific gap, this study aims: (i) to create a susceptibility map of contamination in the areas surrounding the self-burning coal waste pile in São Pedro da Cova, using Analytical Hierarchy Process (AHP) and Fuzzy AHP approaches; and (ii) to develop a webGIS application incorporating all the information acquired that can be useful for the residents of São Pedro da Cova and also to the decision-making public entities and researchers. The results obtained show that the contamination susceptibility is higher surrounding the abandoned mine, particularly along the waste piles and the corresponding runoff areas, which can be especially sensitive. Full article

This study presents robust algorithms for tsunami early warning using synthetic tsunami wave data at ocean bottom sensor (OBS) arrays with sequential multiple linear regression. The study focuses on the Tohoku region of Japan, where an S-net OBS system (150 pressure sensors) has been deployed. To calibrate the tsunami early warning system using realistic tsunami wave profiles at the S-net stations, 4000 stochastic tsunami simulations are employed. Forecasting models are built using multiple linear regression together with sequential feature selection based on Akaike Information Criterion and knee-point method to identify sensors that improve the accuracy most significantly. The study considers tsunami wave amplitude at a nearshore location and regional tsunami loss for buildings to develop hazard-based and risk-based tsunami warning algorithms. The models identify an optimal configuration of OBS stations and waiting time for issuing tsunami warnings. The model performance is compared against a base model, which only uses the earthquake magnitude and epicenter location. The result indicates that estimating the tsunami amplitude and loss via S-net improves accuracy. For the hazard-based forecasting, adding six sensors from the S-net improves the accuracy of the estimation most significantly with an optimal waiting time of 3 min. For the risk-based forecasting, a longer waiting time between 5 and 10 min is suitable. Full article

Considering the global drive toward net-zero carbon emissions in the near future, the need to find clean sources of energy has never been more important. It is estimated that globally there are tens of thousands of depleted and abandoned oil fields that may be adapted to produce green energy. These may be re-cycled with the help of air injection, either from the production of hydrogen, as a direct result of oxidation of oil, or the exploitation of the inherent increase in heat flow and pressure via enhanced geothermal systems. In the past, the use of in-situ combustion (ISC) and high-pressure air injection (HPAI) have experienced many failures, largely due to poor project design and inappropriate reservoir selection. Here, we review data from field applications, experimental studies, and numerical modelling to define the roles of sub-surface sedimentology and petrophysics, structural geology, geomechanics, mineralogy, diagenesis, and petroleum geology on the success of ISC and HPAI. We show how current knowledge can help mitigate project failure via improved project design and initial reservoir selection. Improvements to the design and implementation of ISC and HPAI projects promise to allow the utilisation of the many abandoned oil fields, to produce green energy with the added benefit of the cost-effective, and materials and energy efficient, re-use of existing oil field infrastructure. We conclude that the integration of field data, laboratory experiments, and numerical modelling methods previously studied can be used to help develop ISC and minimize risk of failure. Full article

To increase seismic resilience is one of the challenges the developers of new technologies face to reduce seismic risk. We set up an augmented reality (AR) exhibition with which users’ curiosity was confronted with the opportunity to have a wealth of information on damaging earthquakes that could be a multimedia add-on to the plain “single-layer exhibit”. AR is an emergent technology developed to “augment” reality through various devices; it combines the real world with virtual items, such as images and videos. Our AR exhibition aims to: (i) show the effects of earthquakes even in cases of moderate magnitude; and (ii) promote preventive actions to reduce non-structural damage. It can be customized for different seismic scenarios. In addition, it offers a holistic approach to communicate problems and solutions—with the cost and degree of ease of execution for each solution—to reduce non-structural damage at home, school, and office. Our AR exhibition can do more than just a plain text or a preconceived video: it can trigger fruitful interaction between the presenters, or even the stand-alone poster, and the public. Such interactivity offers an easy engagement to people of all ages and cultural backgrounds. AR is, indeed, extremely flexible in raising recipients’ interest; moreover, it is an appealing tool for the digital native generations. The positive feedback received led us to conclude that this is an effective way to raise awareness and individual preparedness to seismic risk. Full article

Strong crustal earthquakes in Greece are typically followed by aftershocks, the properties of which are important factors in seismic hazard assessment. In order to examine the properties of earthquake sequences, we prepared an earthquake catalog comprising aftershock sequences with mainshocks of M_w ≥ 5.5 from 1995 to 2021. Regional aftershock parameters were estimated to highlight variations in aftershock decay and productivity among regions with similar seismotectonic characteristics. A statistically based method of estimating aftershock duration and a metric of relative aftershock productivity to examine the variations among the different cases were employed. From the detailed analysis of the selected seismic sequences, we attempt to unravel the physical mechanisms behind deviations in aftershock duration and productivity and resolve the relative contribution of background seismicity, the Omori–Utsu law parameters and the mainshock faulting properties. From our analysis, the duration of aftershock sequences depends upon the rupture process of the mainshock, independently of its magnitude. The same applies to aftershock productivity, however, other tectonic setting (e.g., seismic coupling) or source-related (e.g., focal depth, stress drop) parameters also contribute. The estimated regional parameters of the aftershock rate models could be utilized as initial ones to forecast the aftershock occurrence rates at the early stage following a mainshock. Full article

In this work, we investigated the landscape response to the recent activity of the faults affecting the Catanzaro Trough, a seismically active structural basin that developed transversally to the Calabrian Arc (Southern Italy) during the Neogene–Quaternary. We carried out a geomorphological and morphometric study of the drainage networks and basins intercepted by the Quaternary faults that were previously mapped through remote and field analyses. The study confirms the occurrence north of the Catanzaro Trough of a WNW–ESE-oriented left-lateral strike-slip fault system (here named the South Sila Piccola Fault System), which accommodates the differential SE-ward migration of the upper crustal sectors of the Calabrian Arc, and of a south-dipping WNW–ESE-oriented oblique fault system (the Lamezia-Catanzaro Fault System), characterized by a predominant normal component of movement. The latter delimits the Catanzaro Trough and accommodates the transition from a strike-slip regime to an extensional regime in the south. Inside the Catanzaro Trough, we detected for the first time a NNE–SSW-trending, WNW-dipping fault system (here named the Caraffa Fault System). This system contributes to accommodate the extension that occurs orthogonally to the southern sector of the Calabrian Arc. The geomorphological and morphometric analysis revealed the recent activity of these fault systems. In particular, the activity of the Caraffa Fault System is evidenced by the differential uplift and tilting of discrete areas inside the basin. Given its location, geometry, and kinematics, the Caraffa Fault System could be responsible for the occurrence of large historical earthquakes. Full article

The Southern Alps are the retro-vergent belt of the European Alps that developed from Late Cretaceous subduction to Neogene times. The most prominent Alpine thrusts and folds, nowadays sealed off by the Adamello intrusion, were already developed before the continental collision and clasts derived from the eroded pre-collisional wedge can be found in the Cretaceous foredeep sequences. In contrast, the thermal state attained by the Southern Alps during the long-lasting Alpine evolution is still unknown. This contribution provides evidence for Alpine metamorphism in the northern part of the central Southern Alps. Metamorphic conditions are determined for the alkaline Edolo diabase dykes that emplaced in the exhumed Variscan basement rocks before being deformed during the Alpine convergence (D3). The Alpine foliation in the Edolo diabase dykes is marked by actinolite, biotite, chlorite, epidote, albite, and titanite and it developed under greenschist facies conditions at temperature of 350–420 °C and pressure ≤0.2 GPa. The T/depth ratio indicates a minimum of 50–60 °C/km that is compatible with thermal gradients characteristic of arc settings. Based on radiometric ages from the literature, these conditions were attained during the Alpine subduction. Full article

The significance of mineralogical maturity as a provenance indicator has long been debated and we use this study to demonstrate that it can indeed be a powerful tool to track the distribution of sandstone reservoirs. We investigate the cause of the pronounced geographic and stratigraphic differences in mineralogical composition that are found in the Upper Triassic–Lower Jurassic Gassum Formation across the Norwegian–Danish Basin and surrounding areas. Zircon U-Pb dating of 46 sandstone samples including analysis of 4816 detrital grains are combined with quantifications of the detrital mineralogical composition and placed in a sequence stratigraphic framework. The results show that the Gassum Formation can be divided into a southeastern region with high mineralogical maturity and a less mature region to the northwest with more feldspars, rock fragments, micas, and heavy minerals. Both the mineralogical assemblage and the provenance signature have been thoroughly homogenized in the SE region where sediment supplies from the Fennoscandian Shield and the Variscan Orogen are evident. In the NW region, sediment was initially supplied from Fennoscandia only, but the provenance abruptly changed from the Telemarkia Terrane to comprising also the more distant Caledonian Orogen resulting in a different mineralogical assemblage. The change occurred during a basinwide regression and may be caused by tectonic movements in the hinterland that permanently changed the composition of the sediment supplied to the basin. Full article

The Thompson River valley hosts 14 landslides along a 10 km section, which threaten the two major railroads connecting the Port of Vancouver and the interior provinces in Canada. The Ripley landslide is one of the active landslides in this section of the valley. Previous research at this site included an analysis of landslide deformations using satellite radar interferometry focusing on deformations measured in the line of sight between the satellite and the slopes, and average downslope displacement (deformations projected in the average downslope direction). Since then, further stratigraphic interpretation has provided an enhanced understanding of the Ripley landslide. In this update, the new stratigraphic interpretation is supplemented with satellite InSAR data from May 2015 to May 2017 to enhance the current understanding of the landslide kinematics. The results indicate that the Ripley landslide has been moving at a rate between 2 and 82 mm per year, corresponding to a very slow to slow landslide. It is also observed that the movements tend to be near-horizontal on areas closer to the toe of the landslide, while the vertical component of deformation increases near the scarp of the landslide. This, together with the interpreted stratigraphy, indicates the kinematics corresponds to a compound landslide. This is consistent with interpreted landslide kinematics of older, more mature landslides in the area that have shown episodes of retrogression and suggests the possibility of a similar future behaviour of the Ripley landslide. Full article

Upper Triassic carbonate platforms from the Panthalassa Ocean remain less-understood and less-studied than their Tethyan equivalents. This imbalance is largely due to the poorer preservation state of Panthalassan carbonate rock successions in terms of rock quality and depositional geometries, which prevents good appreciation of depositional systems. In this context, carbonate exposures from Lime Peak (Yukon, Canada) represent an outstanding exception. There, the remains of an Upper Norian Panthalassan carbonate platform are well-exposed, show remarkably preserved depositional geometries and overall superior rock preservation. In this work, we analyse the carbonates from the Lime Peak area with particular attention to the vertical and lateral distribution of biotic assemblages and microfacies at the platform scale. Results demonstrate that the Lime Peak platform was surrounded by a basin with an aphotic sea bottom. The carbonate complex developed in warm waters characterized by high carbonate saturation. The area was also defined by moderate to high nutrient levels: this influenced the type of carbonate factory by favouring microbialites and sponges over corals. During its growth, Lime Peak was influenced by tectono-eustatism, which controlled the accommodation space at the platform top, primarily impacting the internal platform environments and the stability of the slope. Gaining better knowledge of the spatial distribution and dynamics of Upper Triassic organisms and sedimentary facies of Panthalassa in relation to tectono-eustatism lays the first foundations for reconstructing more robust platform models and understanding the evolution of other, more dismantled Upper Triassic Panthalassan carbonate systems through time. Full article

The coastal area of the Kavala district, Northern Greece, is characterized by minerals enriched in rare earth elements (REE). The present study focuses on the mineralogy of the black sands from six different locations and the comprehensive mineral chemistry of the REE-bearing minerals, allanite-(Ce), epidote, monazite, thorite, zircon and titanite. Allanite-(Ce) is the most important carrier of light REE (LREE) in the studied black sands, reaching up to 23.24 wt % ΣREE. The crystal chemistry of allanite-(Ce) transitions into ferriallanite-(Ce), due to the significant involvement of Fe³⁺. High resolution backscattered electron (BSE) images were used to identify zoning that corresponds to variations in REE, Th and U. These modifications follow the exchange scheme: (Ca + (Fe³⁺, Al))₋₁(LREE, Y, Th, U + (Fe²⁺, Mg, Mn))₊₁. Epidotes may also contain up to 0.5 REE³⁺ apfu. Monazite and thorite are found as inclusions in allanite-(Ce) and are enriched in Ce, La and Nd, together with Th and U. Some zircons are enriched in Hf, while some titanites host Nb and V. Full article

A lot of work in geosciences has been completed during the last decade on the analysis in the new concept of time, termed natural time, introduced in 2001. The main advances are presented, including, among others, the following: First, the direct experimental verification of the interconnection between a Seismic Electric Signals (SES) activity and seismicity, i.e., the order parameter fluctuations of seismicity exhibit a clearly detectable minimum when an SES activity starts. These two phenomena are also linked closely in space. Second, the identification of the epicentral area and the occurrence time of an impending major earthquake (EQ) by means of the order parameter of seismicity and the entropy change of seismicity under time reversal as well as the extrema of their fluctuations. An indicative example is the M9 Tohoku EQ in Japan on 11 March 2011. Third, to answer the crucial question—when a magnitude 7 class EQ occurs—whether it is a foreshock or a mainshock. This can be answered by means of the key quantities already mentioned, i.e., the order parameter of seismicity and the entropy change of seismicity under time reversal along with their fluctuations. The explanation of the experimental findings identified before major EQs is given in a unified way on the basis of a physical model already proposed in the 1980s. Full article

A strong, shallow earthquake occurred near Heraklion (Crete, Greece) on 27 September 2021. The earthquake produced significant ground deformation in the vicinity of Arkalochori village but without any evidence for surface ruptures of primary origin. We used geodetic (InSAR and GNSS) data to map motions of the Earth’s surface that occurred during and shortly after the earthquake. A 14 cm subsidence of the GNSS station ARKL and a maximum of 19 cm distance from the SAR satellite were recorded. The measured surface displacements were used to constrain the rupture geometry and slip distribution at depth. Our best-fitting inversion model suggests that the rupture occurred on a 13 km-long planar normal fault striking N195° E dipping 55° to the northwest, with major slip occurring to the east and updip of the hypocentre. The fault tip is located 1.2 km beneath the surface. The maximum coseismic slip occurred in the uppermost crust, in the depth interval of 4–6 km. A decrease in the fault offsets toward the Earth’s surface is likely caused by an increased frictional resistance of the shallow layers to rapid coseismic slip. Satellite observations made in the first month after the earthquake detected no post-seismic deformation (i.e., below one fringe or 2.8 cm). The seismic fault may be identified with the Avli (Lagouta) segment of the NNE-SSW striking, west-dipping, 23 km-long neotectonic Kastelli Fault Zone (KFZ). Part of the rupture occurred along the Kastelli segment, indicating a fault segment linkage and a history of overlapping ruptures along KFZ. Based on geological data and footwall topography we estimate an average slip rate between 0.17–0.26 mm/yr for the KFZ. The Arkalochori earthquake is a paradigm example for the on-going extension of Heraklion basin (central Crete) in the WNW-ESE direction, which is almost orthogonal to the E-W Messara graben and other active faults along the south coast of Crete. Full article

The U.S. Pacific Northwest coast must be prepared to evacuate immediately after a Cascadia Subduction Zone earthquake. This requires coastal residents to understand the tsunami threat, have accurate expectations about warning sources, engage in preimpact evacuation preparedness actions, and plan (and practice) their evacuation logistics, including an appropriate transportation mode, evacuation route, and destination. A survey of 221 residents in three communities identified areas in which many coastal residents have reached adequate levels of preparedness. Moreover, residents who are not adequately prepared are willing to improve their performance in most of the areas in which they fall short. However, many respondents expect to engage in time-consuming evacuation preparations before evacuating. Additionally, their estimates of evacuation travel time might be inaccurate because only 28–52% had practiced their evacuation routes. These results indicate that more coastal residents should prepare grab-and-go kits to speed their departure, as well as practice evacuation preparation and evacuation travel to test the accuracy of these evacuation time estimates. Overall, these results, together with recommendations for overcoming them, can guide CSZ emergency managers in methods of improving hazard awareness and education programs. In addition, these data can guide transportation engineers’ evacuation analyses and evacuation plans. Full article

This paper presents a philosophical examination of classical rock engineering problems as the basis to move from traditional knowledge to radical (innovative) knowledge. While this paper may appear abstract to engineers and geoscientists more accustomed to case studies and practical design methods, the aim is to demonstrate how the analysis of what constitutes engineering knowledge (what rock engineers know and how they know it) should always precede the integration of new technologies into empirical disciplines such as rock engineering. We propose a new conceptual model of engineering knowledge that combines experience (practical knowledge) and a priori knowledge (knowledge that is not based on experience). Our arguments are not a critique of actual engineering systems, but rather a critique of the (subjective) reasons that are invoked when using those systems, or to defend conclusions achieved using those systems. Our analysis identifies that rock engineering knowledge is shaped by cognitive biases, which over the years have created a sort of dogmatic barrier to innovation. It therefore becomes vital to initiate a discussion on the subject of engineering knowledge that can explain the challenges we face in rock engineering design at a time when digitalisation includes the introduction of machine algorithms that are supposed to learn from conditions of limited information. Full article

Geological heritage represents and brings together geological elements of great local and global relevance. It also promotes conservation and sustainable use. This study aims to perform a bibliometric analysis of the contributions that address the topics of geological heritage and geosites, using the Scopus and Web of Science databases for the knowledge of trends and research focuses in this area. The methodology consists of: (i) the preparation of the idea and gathering information from a search on the subjects of interest (geoheritage and geosites); (ii) the merging of the databases and applying automated conversions; and (iii) the analysis of the results and the literature review. The first phase of the work identified 2409 and 1635 documents indexed in Scopus and WoS, respectively. The merged global database (2565 documents) identified the following words as analysis topics: geoconservation, geotourism, geopark, and geodiversity. The analysis also revealed the top five countries in scientific contributions as Italy (12.1%), Spain (8.77%), China (5.67%), Portugal (5.35%), and Brazil (5.31%). Finally, most of the publications focus on the characterisation, assessment, and development of geosite initiatives. The main lines of action and contributions to the topics (7.91%) highlight the fact that geoscientists worldwide value geosites for geoconservation and geotourism strategies. Full article