Geosciences

25 pages, 9019 KiB

Open AccessArticle

Petrography and Fluid Inclusions for Petroleum System Analysis of Pre-Salt Reservoirs in the Santos Basin, Eastern Brazilian Margin

by Jaques Schmidt, Elias Cembrani, Thisiane Dos Santos, Mariane Trombetta, Rafaela Lenz, Argos Schrank, Sabrina Altenhofen, Amanda Rodrigues, Luiz De Ros, Felipe Dalla Vecchia and Rosalia Barili

Geosciences 2025, 15(5), 158; https://doi.org/10.3390/geosciences15050158 - 23 Apr 2025

Abstract

The complex interaction of hydrothermal fluids and carbonate rocks is recognized to promote significant impacts on petroleum systems, reservoir porosity, and potential. The objective of this study is to investigate the fluid phases entrapped in the mineral phases of the Barra Velha Formation [...] Read more.

The complex interaction of hydrothermal fluids and carbonate rocks is recognized to promote significant impacts on petroleum systems, reservoir porosity, and potential. The objective of this study is to investigate the fluid phases entrapped in the mineral phases of the Barra Velha Formation (Santos Basin), including their petrographic paragenetic relationships, relative timing, temperatures of migration events, and maximum temperature reached by the sedimentary section. The petrographic descriptions (387), Rock-Eval pyrolysis (107), fluid inclusion petrography (14), and microthermometry (428) were performed on core and sidewall samples from two wells from one field of the Santos Basin. Hydrocarbon source intervals were primarily identified in lithologies with high argillaceous content. Chert samples still retain some organic remnants indicative of their original composition prior to extensive silicification. Redeposited intraclastic rocks exhibit the lowest organic content and oil potential. A hydrothermal petroleum system is identified by fluids consisting in gas condensate, light to heavy undersaturated oil, occasionally accompanied by aqueous fluids influenced by juvenile and evaporitic sources, and localized flash vaporization events. These hydrothermal fluids promoted silicification and dolomitization, intense brecciation, and lead to enhanced porosity in different compartments of the reservoir. The relative ordering of paleo-hydrothermal oils and the main oil migration and accumulation events has improved our understanding of the petroleum systems in the basin. This contribution is significant for future regional research on the evolution of fluid systems and their implications for carbonate reservoirs. Full article

(This article belongs to the Special Issue Petroleum Geochemistry of South Atlantic Sedimentary Basins)

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18 pages, 8681 KiB

Open AccessArticle

First Results of Integrated Geoarchaeological Analyses in the Capua Territory (Campania, Italy)

by Elda Russo Ermolli, Nicola Busino, Fabio Marzaioli, Concetta Rispoli and Ettore Valente

Geosciences 2025, 15(4), 157; https://doi.org/10.3390/geosciences15040157 - 19 Apr 2025

Abstract

This study employs a multidisciplinary approach, integrating geoarchaeology, geomorphology, archaeometry, and palynology to analyze settlement patterns and land use in the surroundings of Capua (southern Italy) during the medieval transition. Borehole sampling and stratigraphic studies indicate significant landscape transformations due to human activity, [...] Read more.

This study employs a multidisciplinary approach, integrating geoarchaeology, geomorphology, archaeometry, and palynology to analyze settlement patterns and land use in the surroundings of Capua (southern Italy) during the medieval transition. Borehole sampling and stratigraphic studies indicate significant landscape transformations due to human activity, particularly deforestation and agricultural expansion. Radiocarbon dating confirms settlement activity from antiquity through the early medieval period. Results suggest that Capua’s elevated position provided natural flood protection, influencing its continuous habitation. Pollen analysis reveals a shift from forested landscapes to open pastures, indicating intensive land use. Future research will focus on refining the chronology and archeological context of this transition, further clarifying Capua’s historical and environmental development. Full article

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19 pages, 13626 KiB

Open AccessArticle

The Afghanistan Earthquake of 21 June 2022: The Role of Compressional Step-Overs in Seismogenesis

by Tejpal Singh, Nardeep Nain, Fernando Monterroso, Riccardo Caputo, Pasquale Striano, R. B. S. Yadav, Chittenipattu Puthenveettil Rajendran, Anil G. Sonkusare, Claudio De Luca and Riccardo Lanari

Geosciences 2025, 15(4), 156; https://doi.org/10.3390/geosciences15040156 - 18 Apr 2025

Abstract

The Afghanistan earthquake of 21 June 2022 ruptured a ~10 km-long fault segment in the North Waziristan–Bannu fault system (NWBFS) located towards the north of the Katawaz Basin. The earthquake was shallow and reportedly caused widespread devastation. In this article, we investigated the [...] Read more.

The Afghanistan earthquake of 21 June 2022 ruptured a ~10 km-long fault segment in the North Waziristan–Bannu fault system (NWBFS) located towards the north of the Katawaz Basin. The earthquake was shallow and reportedly caused widespread devastation. In this article, we investigated the long-term, i.e., geological and geomorphological, evidence of deformation along the earthquake segment. For comparison, we also studied the short-term space geodetic and remote sensing results documenting a visible offset between the fault traces. Focusing on the fault modelling and on the published results, it is thus clear that the earthquake rupture did not reach the surface; instead, it stopped in the shallow sub-surface at ~1 km depth. Moreover, the InSAR analyses show some technical issues, such as coherence loss, etc., likely due to severe ground-shaking leaving some gaps in the results; geological and geomorphological evidence complemented this information. As an outcome of this research, we confirmed that InSAR results could generally capture the overall fault geometry at depth, even in cases of blind faulting, whereas the detailed geometry of the tectonic structure, in this case with a right stepping en-echelon pattern, could be successfully captured by combining it with geological and geomorphological approaches and optical remote sensing observations. Accordingly, the right stepping fault generates a restraining bend in the dominantly left-lateral shear zone. Therefore, such fault stepovers are capable of localizing strain and could act as loci for seismic ruptures, bearing strong implications for the seismic hazard assessment of the region, as well as of other strike-slip fault zones. Full article

(This article belongs to the Special Issue Earthquake Geology of Plate Margins and Plate Interiors: Integrating Classical Methods with New Approaches)

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30 pages, 20652 KiB

Open AccessArticle

Distinct Element Numerical Modelling and In Situ CSIRO HI Cell Data for Rock Slope Stability Assessment

by Vivien De Lucia, Andrea Ermini, Stefano Guido, Daria Marchetti, Domenico Gullì and Riccardo Salvini

Geosciences 2025, 15(4), 155; https://doi.org/10.3390/geosciences15040155 - 18 Apr 2025

Abstract

Understanding the in situ stress state and mechanical properties of rock masses is essential for ensuring the stability and safety of quarrying operations. This study aims to estimate the natural stress state of rock using the CSIRO HI (Hollow Inclusion) triaxial overcoring method; [...] Read more.

Understanding the in situ stress state and mechanical properties of rock masses is essential for ensuring the stability and safety of quarrying operations. This study aims to estimate the natural stress state of rock using the CSIRO HI (Hollow Inclusion) triaxial overcoring method; we also conducted numerical modelling by applying the Distinct Element Method (DEM) for stability assessments in quarry environments. The investigation provided comprehensive insights into the geomechanical properties of the rock mass and the stability of quarry fronts. Precise measurements and analyses of in situ stress contributed to a detailed understanding of stress distribution within the rock. Additionally, biaxial compression tests further characterized the mechanical behavior of the rock, which was essential for accurate modelling and simulation. Numerical modelling using DEM facilitated an in-depth stability analysis, allowing evaluation of potential failure mechanisms and proposal of effective mitigation strategies. The 3D numerical model was calibrated using in situ measurements from CSIRO HI data and was employed to simulate future excavations. DEM modelling was particularly crucial because of the fractured nature of the rock mass, which necessitated thorough stability verification in excavation design simulations. This research advances the scientific understanding of stress distribution and mechanical behavior in jointed rock masses, ultimately contributing to the development of safer and more efficient quarrying practices. Full article

(This article belongs to the Section Geomechanics)

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19 pages, 9813 KiB

Open AccessTechnical Note

EGMStream Webapp: EGMS Data Downstream Solution

by Francesco Becattini, Camilla Medici, Davide Festa and Matteo Del Soldato

Geosciences 2025, 15(4), 154; https://doi.org/10.3390/geosciences15040154 - 17 Apr 2025

Abstract

The European Ground Motion Service (EGMS), part of the Copernicus Land Monitoring Service (CLMS), provides free pan-European ground motion data to support local and regional ground deformation analyses. To enhance the accessibility and usability of EGMS products, a new webapp, EGMStream, has been [...] Read more.

The European Ground Motion Service (EGMS), part of the Copernicus Land Monitoring Service (CLMS), provides free pan-European ground motion data to support local and regional ground deformation analyses. To enhance the accessibility and usability of EGMS products, a new webapp, EGMStream, has been developed using Python and JavaScript for downloading and converting EGMS data. This revised and updated version improves the functionality and performance of the original R-based desktop tool, avoiding the need for a standalone software installation. Users can now simply access the webapp with an internet connection. In addition, the web version enhances data processing by leveraging high-performance server-side computing without relying on personal computer resources. The EGMStream webapp offers advanced features, including the parallel processing of large datasets and extraction of converted EGMS data for areas of interest (AoI) in various GIS-compatible formats. The transition from standalone software to a cloud-based system streamlines the integration of EGMS data into existing workflows, broadens user accessibility, and supports large-scale geospatial analysis. Consequently, this shift promotes the dissemination of these relevant and free available measurement data to a wider audience, including non-expert users. Full article

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Graphical abstract

15 pages, 14363 KiB

Open AccessArticle

Sedimentary Diversity of Tsunami Deposits in a River Channel Associated with the 2024 Noto Peninsula Earthquake, Central Japan

by Rina Okada, Koji Umeda, Keigo Motegi, Takanobu Kamataki and Tadashi Amano

Geosciences 2025, 15(4), 153; https://doi.org/10.3390/geosciences15040153 - 17 Apr 2025

Abstract

A comprehensive analysis of modern tsunami deposits offers a valuable opportunity to elucidate the characteristics of paleo-tsunami deposits. On 1 January 2024, a tsunami was generated by a magnitude 7.6 seismic event and subsequently struck the Noto Peninsula in central Japan. In order [...] Read more.

A comprehensive analysis of modern tsunami deposits offers a valuable opportunity to elucidate the characteristics of paleo-tsunami deposits. On 1 January 2024, a tsunami was generated by a magnitude 7.6 seismic event and subsequently struck the Noto Peninsula in central Japan. In order to create a facies model of the tsunami deposits in terrestrial and riverine environments, field surveys were conducted on both the onshore and sandbars within the river channel in the Nunoura area on the northeastern Noto Peninsula. Terrestrial tsunami deposits were observed up to several hundred meters inland, with a slight decrease in thickness of several centimeters with distance from the shoreline. In terrestrial settings, the presence of a substantial silty layer overlying a graded sandy layer is indicative of ponded stagnant water from the tsunami wave. In contrast, riverine tsunami deposits are thicker and more extensive than terrestrial sediments, containing both gravels and shell fragments. An erosional surface develops between deposits of run-up and backwash flows, but a mud drape is not observed. Full article

(This article belongs to the Special Issue Editorial Board Members' Collection Series: Natural Hazards)

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31 pages, 16165 KiB

Open AccessReview

Reappraisal of the Continental Rifting and Seafloor Spreading That Formed the South China Sea

by Brian Taylor

Geosciences 2025, 15(4), 152; https://doi.org/10.3390/geosciences15040152 - 16 Apr 2025

Abstract

Recently published marine geophysical and seafloor drilling data permit a substantive reappraisal of the rifting and spreading that formed the South China Sea (SCS). The SCS rifted margins are different from those of the Atlantic type, having higher strain rates, younger orogenic crust, [...] Read more.

Recently published marine geophysical and seafloor drilling data permit a substantive reappraisal of the rifting and spreading that formed the South China Sea (SCS). The SCS rifted margins are different from those of the Atlantic type, having higher strain rates, younger orogenic crust, and distributed syn-rift magmatism. Rifting ~66–11 Ma and spreading 30–14 Ma split a Cretaceous Andean arc and forearc, producing >700 km of seafloor spreading in the east and a ~2000-km-wide rifted margin in the west. Luconia Shoals–Dangerous Grounds–Reed Bank–north Palawan–SW Mindoro were separated from China when the SCS opened. Brittle faulting of the upper crust was decoupled from ductile flow and magmatic intrusion of the lower crust, producing wide rifting with thin spots held together by less extended surrounds. Sediments accumulated in inter-montane lakes. Transform faults formed at/after breakup to link offset spreading segments. Spreading in the eastern subbasin from C11n to C5AD was at rates averaging 62 mm/yr, 30–24 Ma, decreasing to 38.5 mm/yr younger than 23 Ma. Spreading reorganization was common as margin segments broke up to the SW and spreading directions changed from ~N-S before 23 Ma to NW-SE after 17 Ma. Full article

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21 pages, 3328 KiB

Open AccessReview

Review and Inventory of Pedological and Stratigraphical Knowledge for Investigating Shallow Landslides: A Case Study of the Cervinara Area (Central Campanian Apennines, Southern Italy)

by Antonella Ermice, Carla Buffardi, Rossana Marzaioli, Marco Vigliotti and Daniela Ruberti

Geosciences 2025, 15(4), 151; https://doi.org/10.3390/geosciences15040151 - 16 Apr 2025

Abstract

Landslides are one of the most serious problems affecting large parts of the world. There are two approaches that are used to study the organization of these land cover features: firstly, an approach utilizing lithostratigraphic tools, where soils are described and interpreted in [...] Read more.

Landslides are one of the most serious problems affecting large parts of the world. There are two approaches that are used to study the organization of these land cover features: firstly, an approach utilizing lithostratigraphic tools, where soils are described and interpreted in accordance with specific geological/lithological patterns, and, secondly, through pedological instruments, where the pedogenetic patterns are identified, and the sequences are identified via standardized criteria and organized according to modern classification systems. In the present review, a comparison between the two above approaches is outlined, using the Campania Apennine reliefs (Southern Italy) as the reference environment because they are periodically and dramatically affected by mass movements mainly associated with rainfall events. These reliefs are strongly influenced by the products emitted by the Phlegraean Fields and the Somma–Vesuvius volcanoes. These products affect surface structures either through their direct alteration, with the formation of pedogenized products, or through their reworking, mainly stimulated by rainfall events, which is also responsible for the movement of pedogenized materials along the slopes. This results in complex surface architectures, knowledge of which is a crucial step in the assessment of robust monitoring systems. This review covers the Cervinara area, located in the central portion of the Campania Apennines, which was overwhelmed by dramatic landslide events in 1999. Our aims were to critically analyze the impact and the potential of lithostratigraphic and pedological approaches in studying the soils of the area in question and to provide an inventory of the scientific papers in which, with different aims, descriptions and interpretations of the local soil covers are reported. We examined and selected the national and international literature available in major scientific online databases, and these were split into groups on the basis of citations and type of approach. The reviewed literature showed that the stratigraphic approach was by far the most preferred, although significant potential was offered by pedological tools in this field of investigation. A high number of hydraulic and geotechnical articles was also found, in comparison to geological and pedological papers, which confirmed the significant levels of interest in the land cover type in question, specifically regarding landslide processes, and in their role in risk mitigation practices. On the whole, the latter approach has been proven to offer a greater exploration potential through the use of rigorous classification systems and, thus, the possibility of identifying and correlating soil properties over large areas. Full article

(This article belongs to the Special Issue Landslides Runout: Recent Perspectives and Advances)

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39 pages, 37908 KiB

Open AccessArticle

Deformation of the “Anorogenic” Wolf River Batholith, Wisconsin, USA: Understanding the Baraboo Orogeny Hinterland

by John P. Craddock, David H. Malone, Erica P. Craddock, Steven J. Baumann, John E. Malone and Ryan Porter

Geosciences 2025, 15(4), 150; https://doi.org/10.3390/geosciences15040150 - 16 Apr 2025

Abstract

The Mesoproterozoic (~1470 Ma) Wolf River batholith (WRB) is exposed over 6500 km², encompassing 11 plutons that crosscut the Archean Marshfield and Proterozoic Penokean terranes. As the WRB is the classically defined anorogenic batholith, to test this hypothesis, seven igneous phases [...] Read more.

The Mesoproterozoic (~1470 Ma) Wolf River batholith (WRB) is exposed over 6500 km², encompassing 11 plutons that crosscut the Archean Marshfield and Proterozoic Penokean terranes. As the WRB is the classically defined anorogenic batholith, to test this hypothesis, seven igneous phases were analyzed using anisotropy of magnetic susceptibility (AMS), as a proxy for magmatic flow during intrusion, and the samples recorded a sub-horizontal emplacement in six different orientations. Paleopoles from six of eight igneous samples preserve a wide variety of sub-vertical orientations with two reversed and four normal polarities. The synorogenic Baldwin Conglomerate is the youngest rock (<1460 Ga) associated with WRB. Magnetic fabrics are horizontal, but multidomain and paleopole signatures, where interpretable, are sub-vertical. The North American APWP places middle Laurentia at low-latitude during Geon 14, and all our paleopoles are sub-vertical, not sub-horizontal, again suggesting post-intrusion deformation. Moreover, the McCauley gneiss (1886 Ma; U-Pb zircon), Rib Mountain Quartzite (1750 Ma MDA; U-Pb zircon, n = 150), Dells of the Eau Claire rhyolite (1483 Ma; U-Pb zircon, 1469 Ma; monazites-in-garnet), and Baldwin conglomerate (1460 Ma MDA; U-Pb zircons, n = 150) are sub-vertical inliers (xenoliths) in the igneous suite; the Proterozoic Wausau turbidite (1850 Ma MDA; U-Pb zircon, n = 150) was intruded by the WRB and dips 25°W. Here, we present a reinterpretation of the WRB as a deformed synorogenic rather than an anorogenic intrusion. Full article

(This article belongs to the Special Issue Zircon U-Pb Geochronology Applied to Tectonics and Ore Deposits)

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31 pages, 5534 KiB

Open AccessArticle

Safety Assessment of Concrete Gravity Dams: Hydromechanical Coupling and Fracture Propagation

by Maria Luísa Braga Farinha, Nuno Monteiro Azevedo and Sérgio Oliveira

Geosciences 2025, 15(4), 149; https://doi.org/10.3390/geosciences15040149 - 15 Apr 2025

Abstract

For the safety assessment of concrete dam–foundation systems, this study used an explicit time-stepping small-displacement algorithm, which simulates the hydromechanical interaction and considers the discrete representation of the foundation discontinuities. The proposed innovative methodology allows for the definition of more reliable safety factors [...] Read more.

For the safety assessment of concrete dam–foundation systems, this study used an explicit time-stepping small-displacement algorithm, which simulates the hydromechanical interaction and considers the discrete representation of the foundation discontinuities. The proposed innovative methodology allows for the definition of more reliable safety factors and the identification of more realistic failure modes by integrating (i) softening-based constitutive laws that are closer to the real behavior identified experimentally in concrete–concrete and concrete–rock interfaces; (ii) a water height increase that can be considered in both hydraulic and mechanical models; and (iii) fracture propagation along the dam–foundation interface. Parametric studies were conducted to assess the impact of the mechanical properties on the global safety factors of three gravity dams with different heights. The results obtained using a coupled/fracture propagation model were compared with those from the strength reduction method and the overtopping scenario not considering the hydraulic pressure increase. The results show that the safety assessment should be conducted using the proposed methodology. It is shown that the concrete–rock interface should preferably have a high value of fracture energy or, ideally, higher tensile and cohesion strengths and high associated fracture energy. The results also indicate that with a brittle concrete–rock model, the predicted safety factors are always conservative when compared with those that consider the fracture energy. Full article

(This article belongs to the Special Issue Fracture Geomechanics—Obstacles and New Perspectives)

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18 pages, 14419 KiB

Open AccessArticle

U-Pb Zircon Age Constraints on the Paleozoic Sedimentation, Magmatism and Metamorphism of the Sredogriv Metamorphics, Western Balkan Zone, NW Bulgaria

by Nikolay Bonev, Petyo Filipov, Tsvetomila Vladinova, Tanya Stoylkova, Hristiana Georgieva, Svetoslav Georgiev, Hristo Kiselinov and Lyubomirka Macheva

Geosciences 2025, 15(4), 148; https://doi.org/10.3390/geosciences15040148 - 15 Apr 2025

Abstract

The Sredogriv greenschist facies rocks belong to the Western Balkan Zone in northwestern Bulgaria. The low-grade rocks consist of clastic-tuffaceous precursors and presumably olistostromic magmatic bodies. We present U-Pb LA-ICP-MS zircon age constraints for the Sredogriv metaconglomerate, intruding metaalbitophyre and a breccia-conglomerate of [...] Read more.

The Sredogriv greenschist facies rocks belong to the Western Balkan Zone in northwestern Bulgaria. The low-grade rocks consist of clastic-tuffaceous precursors and presumably olistostromic magmatic bodies. We present U-Pb LA-ICP-MS zircon age constraints for the Sredogriv metaconglomerate, intruding metaalbitophyre and a breccia-conglomerate of the sedimentary cover. Detrital zircons in the Sredogriv metaconglomerate yield a maximum depositional age of 523 Ma, with a prominent NeoproterozoicEarly Cambrian detrital zircon age clusters derived from igneous sources. The metaalbitophyre crystallized at 308 Ma and contains the same age clusters of inherited zircons. A 263 Ma maximum age of deposition is defined for a breccia-conglomerate of the Smolyanovtsi Formation from the sedimentary cover that recycled material from the Sredogriv metamorphics and Carboniferous–Permian magmatic rocks. The depositional setting of the Sredogriv sedimentary succession is characterized by proximity to Cadomian island arc sources and provenance from the northern periphery of Gondwana. The timing of the Variscan greenschist facies metamorphism of the Sredogriv metamorphics is bracketed between 308 Ma and the depositional age of 272 Ma of another adjacent clastic formation. These results constrain the timing of the Cadomian sedimentary history and the Variscan magmatic and tectono-metamorphic evolution in this part of the Western Balkan Zone. Full article

(This article belongs to the Special Issue Detrital Minerals Geochronology and Sedimentary Provenance)

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30 pages, 2254 KiB

Open AccessReview

Seismicity Precursors and Their Practical Account

by Vasilis Tritakis

Geosciences 2025, 15(4), 147; https://doi.org/10.3390/geosciences15040147 - 14 Apr 2025

Abstract

Earthquakes (EQs) are the most unpredictable and damaging natural disasters. Over the last hundred years, the scientific community has been engaged in an intense endeavor to attain a confident and secure method of seismic activity forecasting. So far, despite these efforts, no fully [...] Read more.

Earthquakes (EQs) are the most unpredictable and damaging natural disasters. Over the last hundred years, the scientific community has been engaged in an intense endeavor to attain a confident and secure method of seismic activity forecasting. So far, despite these efforts, no fully validated method for predicting EQs has been established. However, research over the last thirty years has documented a substantial number of seismic precursor phenomena, the correct evaluation and application of which may pave the way for the development of a reliable EQ prediction method in the near future. Most documented seismic precursors belong to the rapidly evolving field of electro-seismology, while a smaller subset falls within the traditional domain of classical seismology and geophysics. This article aims to compile, classify, and assess the most well-documented precursors while also proposing a preliminary framework for their more effective application. Full article

(This article belongs to the Special Issue Precursory Phenomena Prior to Earthquakes (2nd Edition))

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18 pages, 1727 KiB

Open AccessArticle

Comparison of Backprojection Techniques for Rupture Propagation Modelling of the M_w = 7.8 Mainshock Earthquake near Kahramanmaras and the M_w = 7.5 Second-Largest Mainshock near Elbistan, Turkey, 2023

by Dimitrios Nikolopoulos, Mahmood Sultan, Aftab Alam, Demetrios Cantzos, Georgios Priniotakis, Michail Papoutsidakis, Farhan Javed, Georgios Prezerakos, Jamil Siddique, Muhammad Ali Shah, Muhammad Rafique and Panayiotis Yannakopoulos

Geosciences 2025, 15(4), 146; https://doi.org/10.3390/geosciences15040146 - 14 Apr 2025

Abstract

This paper utilises teleseismic Z-component data to investigate rupture propagation, extent, and velocity for two very destructive earthquakes in the East Anatolian Fault Zone (EAFZ): the

M_{w}

= 7.8 earthquake near Kahramanmaras and the largest (

M_{w}

= 7.5 s) aftershock [...] Read more.

This paper utilises teleseismic Z-component data to investigate rupture propagation, extent, and velocity for two very destructive earthquakes in the East Anatolian Fault Zone (EAFZ): the

M_{w}

= 7.8 earthquake near Kahramanmaras and the largest (

M_{w}

= 7.5 s) aftershock at Elbistan (both on 6 February 2023). The extent of the rupture is modelled with beamforming and multichannel signal classification. The teleseismic data are derived from agencies in USA and Canada. The rupture of the

M_{w}

= 7.8 earthquake is found to be bi-directional towards the northeast and southwest. Three rupture segments are identified for the Kahramanmaras earthquake between 34.5°–37.5° longitude and 37.0°–37.5° latitude, and another three are identified for the Elbistan earthquake between 36.5°–38.0° longitude and around 38.5° latitude. A total of 299 km is covered in 185 s with rupture velocities between 3.1 km/s and 3.4 km/s. Additionally, the mainshock’s splay and the second-largest aftershock’s rupture are also bidirectional, covering 150 km within 46 s. Five velocity segments are identified, three for the Kahramanmaras and two for the Elbistan earthquakes. Beamforming is efficient for identifying the velocity segments. The findings provide new insights on the evolution of the spatio-temporal rupture of the EAFZ and may serve as a basis for long-term earthquake hazard planning in the area. Full article

(This article belongs to the Special Issue Editorial Board Members' Collection Series: Natural Hazards)

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15 pages, 4901 KiB

Open AccessArticle

Effects of Rock Texture on Digital Image Correlation

by Azemeraw Wubalem, Chiara Caselle, Battista Taboni and Gessica Umili

Geosciences 2025, 15(4), 145; https://doi.org/10.3390/geosciences15040145 - 10 Apr 2025

Abstract

Digital image correlation (DIC) is a non-contact optical method that can provide high-resolution strain and displacement measurements, but its effectiveness depends on surface texture contrast. This study investigates the effects of surface characteristics on the quality of DIC results in tonalite and marble [...] Read more.

Digital image correlation (DIC) is a non-contact optical method that can provide high-resolution strain and displacement measurements, but its effectiveness depends on surface texture contrast. This study investigates the effects of surface characteristics on the quality of DIC results in tonalite and marble samples under Brazilian tests. Tonalite samples have a coarse texture with a heterogeneous mineral composition; therefore, DIC analysis was conducted without artificial speckle patterns. Marble, instead, poses a challenge due to its uniform fine texture and composition. Thus, using point and line grids to enhance surface contrast, artificial speckle patterns were applied to marble samples. A total of 39 disk samples (12 tonalite and 27 marble) were tested with video frames recorded during loading and analyzed using Ncorr software. The results confirmed that tonalite’s natural texture allows accurate strain mapping without artificial speckle patterns. In contrast, marbles without speckles are not effective in strain evolution mapping due to a lack of surface contrast. Marble with both point- and line-speckled patterns effectively mapped the strain evolution except for some distortion and directionality along speckles in displacement fields. This result suggests that the preparation of speckled surfaces need special attention for effective deformation evolution mapping in homogeneous materials. Full article

(This article belongs to the Special Issue Digging Deeper: Insights and Innovations in Rock Mechanics)

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10 pages, 248 KiB

Open AccessArticle

Vibrations of an Elastic Half-Space

by Bogdan Felix Apostol

Geosciences 2025, 15(4), 144; https://doi.org/10.3390/geosciences15040144 - 9 Apr 2025

Abstract

We report on the resolution of the vibration problem for a homogeneous and isotropic elastic half-space (the Lamb problem), with application to the seismic tensorial force. We assume a homogeneous and isotropic half-space with a localized force which produces vibrations. The solution is [...] Read more.

We report on the resolution of the vibration problem for a homogeneous and isotropic elastic half-space (the Lamb problem), with application to the seismic tensorial force. We assume a homogeneous and isotropic half-space with a localized force which produces vibrations. The solution is achieved by introducing vector plane-wave functions. Explicit results are given for an isotropic tensorial force and a half-space with free surface. The contribution of the Rayleigh surface waves to vibrations is analyzed in the special case of a temporal-impulse force, where the solution exhibits unphysical features, as expected: it extends over the entire free surface and time domain, with a (scissor-like) double-wall propagating both in the future and the past. Full article

(This article belongs to the Special Issue Editorial Board Members' Collection Series: Natural Hazards)

33 pages, 44898 KiB

Open AccessArticle

The Supra-Salt Sedimentary Sequence of the North Caspian Depression: Stratigraphy and Sedimentary History

by Aitbek Akhmetzhanov, Saule Uvakova, Kenzhebek Ibrashev, Gauhar Akhmetzhanova and Vyacheslav Zhemchuzhnikov

Geosciences 2025, 15(4), 143; https://doi.org/10.3390/geosciences15040143 - 9 Apr 2025

Abstract

The North Caspian Basin, known for its oil and gas potential, was formed because of the evolution of the ancient Tethys Ocean and is also a result of the collision of the East European, Kazakhstania, and Siberian paleocontinents. At the beginning of the [...] Read more.

The North Caspian Basin, known for its oil and gas potential, was formed because of the evolution of the ancient Tethys Ocean and is also a result of the collision of the East European, Kazakhstania, and Siberian paleocontinents. At the beginning of the Mesozoic Era, it was a part of the northern continental margin of the Neo-Tethys, which formed Eurasia. In the Late Triassic and Early Jurassic, a major restructuring of the North Caspian sedimentary basin occurred, characterized by angular unconformity and the erosion of underlying sediments in the coastal zones of the basin. The sedimentary succession of the depression accumulating in the Mesozoic Era consisted of alternating siliciclastic and carbonate rocks. It began to form due to the destruction of the uplifts formed north and west of the East European craton and Urals, which resulted in coastal clastic material in the Triassic and Jurassic, but by the end of the Jurassic and Cretaceous, when all uplifts existing in the north of Tethys were leveled, it was mostly marine environments that contributed to the accumulation of siliciclastic and carbonate strata. The appearance of a large amount of sedimentary material towards the center of the depression, causing stress, as well as the deflection of the basement, contributed to fault tectonics and the resumption and manifestation of salt tectonics. As a result of the continuous diapirism of salt bodies during the Late Mesozoic, mini basins were formed, in which different sedimentogenesis was manifested. These processes contributed to the redistribution of hydrocarbons from the underlying pre-salt formations to the intermediate depth interval post-salt succession with Permian–Triassic and also near-surface Jurassic–Cretaceous formations. Full article

(This article belongs to the Section Sedimentology, Stratigraphy and Palaeontology)

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46 pages, 9978 KiB

Open AccessReview

Experimental and Numerical Methods for Hydraulic Fracturing at Laboratory Scale: A Review

by Atif Ismail and Saman Azadbakht

Geosciences 2025, 15(4), 142; https://doi.org/10.3390/geosciences15040142 - 9 Apr 2025

Abstract

Hydraulic fracturing experimentation is an essential tool for understanding the application of hydraulic fracturing in producing hydrocarbons from unconventional reservoirs. Laboratory testing methods such as uniaxial, biaxial, and true triaxial testing have limited accuracy due to the simplified consideration of in situ stresses, [...] Read more.

Hydraulic fracturing experimentation is an essential tool for understanding the application of hydraulic fracturing in producing hydrocarbons from unconventional reservoirs. Laboratory testing methods such as uniaxial, biaxial, and true triaxial testing have limited accuracy due to the simplified consideration of in situ stresses, geological conditions, and subsurface temperature variations. Despite these limitations, hydraulic fracturing experimentation provides valuable insights for the execution of hydraulic fracturing in field conditions. Key factors influencing the accuracy and generalization of experimental results include sample specifications, stress regime, saturation conditions, and fracturing fluid properties. However, extending laboratory-scale conclusions to the field scale requires appropriate scaling factors. This paper provides an overview of the main concepts in hydraulic fracture modeling, including design considerations, laboratory scaling, uniaxial, biaxial, and triaxial testing in hydraulic fracturing experimentation and major numerical simulation methodologies. Numerical methods, such as the discrete element method, discontinuous deformation analysis, rigid body spring network, and virtual internal bond, effectively simulate complex mechanisms like fracture initiation, propagation, fracture–fluid interactions, and the influence of rock microstructure, complementing the experimental findings. Advancements in these models, including the integration of nonlinear elasticity in virtual internal bonds and coupling with finite element analysis or fluid network models, continue to enhance the predictive accuracy and efficiency, particularly in complex geological settings, offering promising applications for optimizing shale gas production, acid fracturing, and geotechnical engineering. Furthermore, this review discusses the importance of in situ stresses, geological conditions, and temperature in both laboratory experiments and numerical simulations, highlighting future directions to consider in laboratory-scale analyses of hydraulic fracturing. Full article

(This article belongs to the Section Geomechanics)

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27 pages, 4415 KiB

Open AccessArticle

Using a Hydro-Morphic Classification of Catchments to Characterise and Explain High Flow and Overbank Flood Behaviour

by Amir Mohammad Arash, Kirstie Fryirs and Timothy J. Ralph

Geosciences 2025, 15(4), 141; https://doi.org/10.3390/geosciences15040141 - 8 Apr 2025

Abstract

The morphological characteristics of catchments are key controls on how flow is routed through catchments and the spatial and temporal dynamics of floods, therefore influencing the shape of hydrographs at any location. Here, we developed a hydro-morphic catchment classification to understand the extent [...] Read more.

The morphological characteristics of catchments are key controls on how flow is routed through catchments and the spatial and temporal dynamics of floods, therefore influencing the shape of hydrographs at any location. Here, we developed a hydro-morphic catchment classification to understand the extent to which various catchment characteristics act as controls on flood behaviour. The catchment characteristics include: size (as measured by gauge position in catchment and valley confinement at the gauge site), shape (elongation ratio and form factor), topography (catchment relief and longitudinal slope), and drainage network structure (drainage density). A total of 2452 high flow (near bankfull) and overbank flood hydrographs from rivers in 17 coastal catchments of New South Wales (NSW), Australia were used. Cluster analysis on hydrograph shape metrics of kurtosis, skewness, and rate-of-rise was performed to identify classes of hydrographs and their median shape. Three statistically distinct clusters were delineated for both high flows and overbank floods, and categorised as flashy, intermediate, and broad. Topographic characteristics of catchments (i.e., relief and longitudinal slope) were commonly among the dominant controls for all high flow and overbank flood hydrographs, excluding broad overbank floods. Drainage network structure (i.e., drainage density) also controlled flashy and intermediate high flows, and intermediate and broad overbank floods, while catchment size (i.e., gauge position in the network) influenced broad high flows. Catchment shape (i.e., elongation ratio) influenced broad overbank floods, and is a dominant control on flashy high flows, and intermediate and broad overbank floods. Overall, topographic controls were more useful for differentiating the hydrological behaviour of high flows relative to overbank floods. Understanding the relative control of different catchment morphometric characteristics on flow and flood behaviour can be used to identify the aspects of flood behaviour that are set by imposed controls and cannot therefore be realistically manipulated in management. A hydro-morphic classification can also be used in the design and calibration of hydrological models, tailoring their use to hydro-morphic catchment class. Full article

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22 pages, 8797 KiB

Open AccessArticle

Understanding Secondary Fragmentation Characteristics in Cave Mining: A Simulation-Based Analysis of Impact and Compression-Induced Breakage

by Yalin Li and Davide Elmo

Geosciences 2025, 15(4), 140; https://doi.org/10.3390/geosciences15040140 - 8 Apr 2025

Abstract

This study investigates the characteristics of secondary fragmentation and fines generation in cave mining through DEM simulations. The objective is not to develop a tool for accurately estimating fragmentation observed at drawpoints. Instead, the research focuses on an improved understanding of the impact [...] Read more.

This study investigates the characteristics of secondary fragmentation and fines generation in cave mining through DEM simulations. The objective is not to develop a tool for accurately estimating fragmentation observed at drawpoints. Instead, the research focuses on an improved understanding of the impact of critical parameters (tensile strength, damping coefficients, and micro-defects) on secondary fragmentation characteristics. Attempting to predict outcomes without first comprehending the underlying mechanisms risks oversimplifying complex mine-scale conditions. The analysis shows that tensile failure is the dominant mechanism governing fragmentation. Size-distribution curves of fragmented blocks under impact breakage demonstrate a concave-up exponential relationship between percentage mass passing at 1/10th of the original size (

t_{10}

) and kinetic energy. Furthermore, the analysis of compression-induced breakage highlights the significant role of tensile strength and micro-defects in determining the extent of fragmentation under different conditions. By better understanding these underlying mechanisms, the research establishes a solid foundation for predicting fines generation and ultimately enhancing decision making and operational strategies in mining. Full article

(This article belongs to the Section Geomechanics)

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