Abstract: A method for analyzing long-term (1997-2025) continuous records of low-frequency global seismic noise measured at a network of 229 broadband seismic stations distributed across the Earth's surface is proposed. The method is based on the use of nonlinear multifractal and entropy statistics, evaluated daily in successive time intervals. The method is based on the use of first-principal component analysis, correlation analysis, and parametric models of point process intensity. The relationships between changes in seismic noise properties and the response of noise properties to the irregularity of the Earth's rotation with the sequence of strong earthquakes, including those of a predictive nature, are investigated.

Abstract: Organic facies distribution exerts a primary control on hydrocarbon generation potential in clastic-dominated passive margin basins. This study evaluates the spatial and stratigraphic distribution of organic facies and their hydrocarbon potential in the Niger Delta Basin using an extensive organic geochemical dataset. A total of 715 source rock samples from onshore, shallow offshore, and deepwater wells were analyzed using total organic carbon (TOC) and Rock-Eval pyrolysis parameters (S1, S2, S3, HI, OI, Tmax). Organic facies were classified following the Pepper organofacies scheme to assess variations in organic matter type, richness, and generative potential across depositional settings and depobelts. The results show that source rocks of the Akata Formation are dominated by organofacies B and D/E, reflecting mixed marine and terrigenous organic matter with moderate to high hydrogen indices and predominantly oil-prone to mixed oil–gas generative potential. In contrast, source rocks of the Agbada Formation are characterized mainly by organofacies F, dominated by terrestrial organic matter with low hydrogen indices, indicating a gas-prone character. Cretaceous shales beneath the Niger Delta contain mixed organofacies D/E and F and locally exhibit fair to good hydrocarbon potential. TOC values range from 0.1 to 16.9 wt%, with the highest organic richness concentrated within the Akata Formation at depths of approximately 2800–4000 m. Spatial variations in organic facies distribution across depobelts reflect changes in depositional environment, sedimentation rate, and preservation conditions. These results confirm the Akata Formation as the principal effective oil-prone source rock in the Niger Delta Basin and provide important constraints for petroleum system analysis and deepwater exploration risk reduction.

Abstract:

The Dongchuan District of Kunming City lies in the transition zone between the Yunnan-Guizhou Plateau and the Sichuan Basin, hosting numerous landslides that pose a serious threat to local lives and property. Therefore, compiling a comprehensive landslide inventory and analyzing the relationships between landslide spatial distribution and influencing factors are of significant importance for geological hazard prevention. This study focuses on the Dongchuan District. High-resolution remote sensing imagery was interpreted to establish a landslide inventory, and the spatial distribution and geometric characteristics of landslides were systematically analyzed. The results show that a total of 1,623 landslides were identified, covering an area of 10.36 km². Landslides predominantly occur at elevations of 1,000-2,000 m, on slopes of 20°-45°, with aspects of 255°-285°, relief between 150-400 m, annual rainfall below 825 mm, and within a distances of 1,000 m from rivers and 3,000 m from faults. Four landslide clusters were delineated along the Xiao River Fault, highlight the significant influence of the fault on the spatial distribution of landslides. Most landslides are longitudinal in planform, with travel distances (L) of 50-450 m and heights (H) from 25 to 350 m, exhibiting allometric relationships between these parameters and volume. The mean H/L ratio is 0.56 (corresponding to a mean reach angle of 29°), significantly higher than that observed in Baoshan City (mean reach angle of 21°). The results would be helpful for further understanding landslide initiation mechanisms and spatial distribution patterns on the northern margin of the Yunnan-Guizhou Plateau and providing valuable data support for subsequent landslide hazard risk assessment in this region.

Abstract: Since September 2021, numerous seismic events with spectral peak below 1 Hz occurred on the island of Vulcano, Italy, 131 years after its last eruption. The local monitoring network recorded microseismicity mostly in the form of months-long swarms, concurrent with anomalous values of other geophysical and geochemical parameters. By applying a machine learning technique (Self-Organizing Maps, SOM), we obtained an inventory of ~6600 seismic signals, identifying distinct families of events. These families were located below La Fossa Crater (where the last eruption of the volcano happened) from the surface to a depth of 2.2 km b.s.l. Based on the seismic signature and source location of these events, we hypothesize unsealed/sealed processes through a network of shallow fractures favored by fluid pressure. After the return to background values of geochemical and geophysical parameters in 2023, a resumption of microseismicity occurred between May and June 2024. A test application of the SOM to the new data confirmed the non-destructive source of the new recorded signals, which shared families, location, and depths as our previous inventory. This test showcased that SOM can be an effective tool to support monitoring and warning of future unrest at Vulcano.

Abstract: The Noto Peninsula is a seismically active region where spatial patterns and shallow seismic zones play a critical role in understanding earthquake behavior. While visualization techniques for seismicity have advanced, their effective application still requires practical experience and region-specific interpretation, as earthquake susceptibility varies spatially. In this study, we analyze earthquake catalogues and mesh-based magnitude parameters for events occurring between 2023 and 2024 to investigate seismic anomalies in the region. Temporal variations in the magnitude locator and scale, combined with spatial patterns of shallow seismicity, reveal anomalous behavior in the offshore area west of Noto. This area is characterized by persistently elevated locator values and locally reduced scale—features that resemble precursory patterns observed in volcanic settings. The seismic sequences of 5 May 2023 (M6.5) and 1 January 2024 (M7.6) illustrate how such combined signals may precede large events, while also highlighting how aftershock decay and resurgence complicate post-event energy assessments. These findings suggest the possible influence of submarine volcanic or volcano-related structures, as well as ongoing orogenic deformation. The results support the need for continued, targeted monitoring of epicentral activity in this region and may offer insights applicable to other tectonically complex areas.

Abstract: Submarine gas emissions represent a key expression of fluid migration processes in volcanic and hydrothermal marine environments and provide valuable analogues for monitoring strategies relevant to sub-seabed carbon storage. This study investigates the feasibility of using marine Distributed Acoustic Sensing (DAS) to detect natural CO₂ bubble emissions in a shallow-water setting offshore Panarea (Aeolian Islands, Italy). A 1.1 km armored fiber-optic cable was deployed on the seabed and interrogated using two different DAS systems to acquire continuous passive acoustic data. The DAS recordings were complemented by controlled gas releases from scuba tanks to provide reference signals, as well as by independent high-resolution boomer seismic survey and side-scan sonar imaging to characterize the shallow subsurface and seabed morphology. The results show that DAS is sensitive to acoustic signals associated with both artificial and natural bubble emissions, despite the complex acoustic conditions typical of shallow marine environments. The integration of passive DAS monitoring with independent geophysical observations provides a robust framework for interpreting gas-related signals and seabed processes. These findings demonstrate that marine DAS represents a promising geophysical tool for monitoring of submarine volcanic–hydrothermal systems and offers important insights for the development of sub-seabed CO₂ leakage detection in offshore CCS contexts.

Abstract: This article addresses the limitations of traditional petrophysical interpretation and lithofacies analysis methods used in commercial software solutions, such as sub-jectivity, insufficient detail, and reliability, particularly in cases of complex reservoir structures. Accordingly, the development of automated lithofacies analysis tools using Artificial Intelligence (AI) and Machine Learning (ML) is a relevant objective for en-hancing the reliability of geological modeling and reservoir evaluation. The authors have developed an innovative methodological approach for auto-mated lithofacies classification of well logging data, demonstrated via case study of Gran Field. The methodology is centered on the k-means unsupervised clustering al-gorithm, specifically adapted for comprehensive petrophysical data analysis. It is demonstrated that the proposed approach effectively partitions the geological section into lithofacies and ensures the reliability of petrophysical interpretation re-sults. The optimal number of clusters (k=3) was determined using the Silhouette Coef-ficient, and the results were visualized using the Principal Component Analysis (PCA) method, confirming that the identified groups correspond to petrophysical patterns. The clustering results, incorporating PCA, showed clear separation into clay, silt-stone, and sandstone lithofacies. The k-means-based approach mitigates the primary limitations of traditional methods reliant on the subjective selection of cut-off values and forms a reliable foundation for building advanced geological and hydrodynamic models. To facilitate practical application, a Python-based web interface was developed using the Streamlit framework. This application offers a user-friendly interface for preprocessing well-log data, performing clustering, and visualizing results, bridging the gap between advanced ML algorithms and specialists without programming ex-pertise. Comparative analysis reveals that the k-means algorithm outperforms alternative methods across several key metrics, notably in interpretability and the structural co-herence of the results. Future development prospects include the integration of densi-ty-based clustering algorithms, such as DBSCAN, to increase the system's adaptability in complex geological sections. This will open new possibilities for intelligent analyti-cal systems in the field of reservoir evaluation and resource assessment.

Abstract: The Santorini volcano, Greece, attracts global scientific interest and constitutes a top tourist destination. The 17th century BCE eruption, known as the Minoan event, was likely the largest ever occurred in the Holocene. The evaluation of an enriched collection of documentary sources combined with scientific observations showed that during historical times 14 small-to-moderate eruptive episodes were reported from the 2nd century BCE up to 1950 CE. Among them two little-known episodes occurring in 1667 CE and 1773 CE were uncovered and analyzed based on European documentary sources. For the first time a reliability score has been assigned to each one of the 14 episodes. The completeness of the recorded eruption history after the 14th century CE looks like ten times higher than in the previous period but it remains unclear whether this reflects real eruption rate or reporting incompleteness. The eruptions occurring after the 17th century CE are characterized by lower size, in terms of Volcanic Explosivity Index (VEI), than in the previous period. However, this may be due to the incomplete record of earlier eruptions of low VEI magnitude.

Abstract: Highly deviated wells commonly exhibit large errors in horizon calibration because the logging path follows an inclined borehole trajectory, whereas post-stack seismic processing effectively treats wave propagation as vertical. This mismatch has received limited attention. Here we performed horizon calibration and velocity-model building for drilled highly deviated wells in the Mahu Sag, Junggar Basin, and obtained three key findings. First, the assumed vertical travel path in post-stack data is the primary cause of the initial mis-tie for highly deviated wells. Second, calibration in the deviated interval requires a strategy distinct from that of vertical wells and may +involve substantial stretching or squeezing of the original logs to achieve a consistent time–depth relationship. Third, the map-view projection of a highly deviated well is essentially linear; relative to vertical wells, it provides denser in-situ velocity constraints and, with pseudo-well control, supplies 2D velocity information along the well-trajectory plane, thereby improving velocity-field modeling. Validation against drilling data showed that this workflow improved well ties and refined the velocity model, providing practical guidance for geological well planning and reducing drilling risk.

Abstract: In the field of geophysics, several erroneous theories were long accepted as fundamental laws and formulas. Recent corrections to these misconceptions have been made possible through the application of Exploratory Data Analysis (EDA). This article outlines how EDA contributed to these breakthroughs and provides a brief guide for those interested in adopting this approach. In addition, while introducing new data analysis methods based on EDA, I will also discuss the remaining challenges that warrant further clarification.

Abstract: By visualising seismic data in three dimensions, it becomes evident that hypocentres cluster along boundaries formed by colliding plates. These boundaries appear to be solid structures, established years before the mainshock, and remain largely stationary even after the event concludes. Major earthquakes tend to occur along such surfaces, and because seismic activity increases in these regions prior to a mainshock, their observation may provide a basis for earthquake prediction. With plate positions near Japan now more clearly defined, existing models require revision. Furthermore, analysis reveals that both the number of aftershocks and the seismic energy released during a mainshock decay with distinct half-lives. This represents a fundamentally different decay pattern from the formula long regarded as correct. Employing modern statistical methods therefore yields more accurate insights, essential both for advancing our understanding of earthquake mechanisms and for improving predictive capability.

Abstract: Submarine canyon-channel system plays a critical role as potential conduit for warm water upwelling in Antarctica, thereby influencing ice sheet stability. In this study, we identify 29 canyon-channel systems along the Adélie Land margin and conduct sys-tematic morphometric analysis of their length, width, depth, width-to-depth (W/D) ratio, and sinuosity. The results reveal pronounced differences in the distribution and morphological evolution of canyon–channel systems between the Adélie Depression and the Adélie Bank. We propose that these differences are primarily controlled by the shelf-slope topography, sediment supply, and ice sheet dynamic process. As the main catchment area of the Wilkes Subglacial Basin (WSB), the Adélie Depression is fed by a focused, high-flux supply of glacial debris, leading to the development of large-scale progradation wedges and mass transport deposits. These conditions promote the formation of extensive canyon–channel systems with elongated, tortuous, and dendritic morphologies. In contrast, canyon–channel systems on the Adélie Bank are smaller, more isolated, and irregularly distributed, reflecting dispersed and episodic sediment supply combined with strong bottom-current reworking. This study eluci-dates how canyon-channel system morphology responds to the topography, sedi-mentation, and ice dynamics in high-latitude glaciated margins, providing important constraints on sediment transport pathways and ice-sheet–ocean interactions in Antarctica.

Abstract: The article examines the behavior of seismic noise fields over the Japanese islands recorded by the F-net seismic network for 1997-2025. The paper uses nonlinear noise statistics: the entropy of the wavelet coefficient distribution, the Donoho-Johnston (DJ) wavelet index, and the multifractal singularity spectrum support width. These parameters were chosen because their changes reflect the complication or simplification of the noise structure. Changes in the structure of seismic noise properties are analyzed in comparison with a sequence of strong earthquakes. Using a model of the intensity of interacting point processes, the effect of the leading of local noise property extrema relative to the seismic event times is estimated. Using the Hilbert-Huang decomposition, the synchronization of the amplitudes of the envelopes of noise property time series for different IMF levels is estimated. A sequence of weighted probability density maps of extreme values of noise properties is analyzed in comparison with the mega-earthquake of March 11, 2011 and the preparation of a possible next strong seismic event.

Abstract: Marine controlled source electromagnetic (CSEM) surveys have been proven to be an effective tool in hydrocarbon exploration, principally due to the method’s ability (in the right circumstances) to identify electrical resistivity contrasts between hydrocarbon-saturated and brine-saturated sedimentary units. However the sensitivity of such surveys decreases in shallow water, for deeper targets, and for targets with limited horizontal extent. In principle, the resolution and sensitivity of a survey can be improved by moving either the transmitting or the receiving dipoles into the sub-surface. We have therefore investigated the sensitivity of Seafloor to Borehole CSEM (sbCSEM) survey geometries, specifically for the case of targets with small lateral dimensions in shallow water areas – including targets whose depth of burial substantially exceeds their lateral extent. The results are encouraging. Neither small target size nor shallow water present obstacles in principle to the use of this approach. Our models reveal distinct lobes in the patterns of electric field and current density amplitudes around a sub-seafloor transmitting dipole. The shape, positions and amplitudes of these lobes are all strongly modified by the presence of one or more small resistive targets, and in particular are strongly influenced by the positions of target edges. These effects significantly modify the pattern of electric fields at the seafloor, and hence result in good sensitivity for realistic survey geometries. Small targets can be detected by seafloor receivers when the sub-seafloor transmitting dipole is located at some distance laterally outside the targets - leading to potential applications in ‘step-out’ prospecting. The asymmetry of responses at the seafloor from targets that are offset with respect to transmitter location has potential applications in field appraisal; while monitoring of reservoirs during production provides another possible application. Varying the depth of the transmitter down the borehole generates a Vertical EM Profiling (VEMP) survey – analogous to Vertical Seismic Profiling (VSP) – and we demonstrate that this too can have useful applications. Modelling for deeper (3 km sub-seafloor) targets continues to yield encouraging results, and suggests that step-out sbCSEM may be effective at depths beyond the detection limit of conventional seafloor-seafloor CSEM.

Abstract: To address critical issues in traditional quality control methods for discrete Eulerian solutions in underwater magnetic target detection—such as excessive filtering of valid solutions during divergence suppression, parameter settings reliant on subjective experience, and insufficient noise resistance—this study proposes a novel approach combining the Artificial Protozoa Optimizer (APO) with DBSCAN clustering. Based on the distribution characteristics of discrete Euler solutions, an optimization objective function incorporating Euler solution residual penalty terms and contour line coefficients was constructed. The APO algorithm identifies DBSCAN clustering parameters that minimize this objective function, thereby enhancing clustering precision and accuracy. This method selects optimal Euler solution sets, enabling high-precision localization of magnetic targets. Simulation and field test results demonstrate that compared to statistical screening methods, the optimized algorithm achieves a 52.52% and 76.33% increase in the retention rate of valid solutions for noise-free and noisy data, respectively, while reducing the retention rate of invalid solutions by 28.57% and 94.21%. In field data, the average deviation from the true center of gravity is reduced by 26.37%.

Abstract: Coastal lakes are vulnerable complex systems where potential contamination processes may affect the bottom sediments, especially if the coasts are intensively urbanized. In this respect, the sedimentological and ecological characterization of the bottom sediments may provide a fundamental background, particularly stringent in the cases of heavy metal contamination. In this paper, this multi-disciplinary approach was applied to Lake Ganzirri, a small-size and shallow coastal lake developed on an intensively urbanized territory of North-Eastern Sicily (Italy), where recent chemical investigations on the heavy metal contaminants of the sediments were carried out. The sediment textural features (in-cluded those of the malacofauna) and the bottom morpho-bathymetry were characterized and investigated by applying multivariate statistics and QGIS techniques. QGIS maps were finally compared with those of the heavy metal concentrations. The present research allowed to detect for the first time: i) a minor tectonic graben inside the main ENE-WSW trending Ganzirri graben; ii) mixed sediments composed of quartzo-lithic sands with sig-nificant contents in bioclastic calcareous remains; iii) sediment heterogeneous textures, mainly characterized by poorly sorted, leptokurtic, near symmetrical coarse-grained sands, with randomly distributed lenses of very coarse- grained sands with gravels and of medium-grained sands; iv) sediments testifying for actual high-energy conditions and environments at low confinement degree; v) no evidence of correlations between the hotspots of heavy metals (mainly related to prevalent geogenic origins) and the distribu-tions of sedimentological features and bottom depths.

Abstract: The Indonesian archipelago represents one of the most tectonically complex regions on Earth, where the convergence and interaction of multiple plates drive ongoing subduction, arc-continent collision, and lithospheric accretion. To unravel the detailed structure and dynamics of this convergent margin, we develop a novel, high-resolution 3-D shear-wave velocity model of the lithosphere and upper mantle. This model is derived from a weighted joint inversion of complementary surface-wave datasets: teleseismic Rayleigh waves from 387 shallow earthquakes (MS ≥ 5.5) recorded across 31 stations, analyzed using a modified two-plane-wave tomography method, and ambient-noise correlations from two years of continuous data at 30 stations, processed with far-field approximation and image-transformation techniques. This integrated approach significantly enhances the resolution of shallow structures compared to previous body-wave tomographic models. Our model provides new insights into the four primary subduction systems. Along the Sunda-Java trench, we document a systematic along-strike transition in slab geometry: a continuous, well-defined slab in the west progressively gives way to increasingly disrupted and thickened structures eastward. This morphological evolution correlates with the subduction of progressively older oceanic lithosphere and is influenced by variations in slab age, dip, and the presence of deep slab tearing. Beneath the Banda Arc, we image an approximately 200 km-thick slab and attribute its dramatic 180° curvature to the mechanical interaction between the northward-subducting Australian plate and a distinct south-directed subduction system beneath the Seram region. In the Molucca Sea, our high-resolution tomography reveals a shallow (~50 km depth) low-velocity zone and details the complex geometry of an active double-sided subduction zone, characterized by asymmetric dips and intense seismicity, which illuminates the dynamics of ongoing arc-arc collision. Finally, beneath the Celebes Sea, a south-dipping slab is clearly resolved under North Sulawesi, while no substantial subduction signature is associated with the Sangihe Arc. Collectively, these findings provide unprecedented structural constraints on the segmentation, deformation, and interaction of subducting slabs in Indonesia. They underscore the control of lithospheric age and complex plate interactions on slab morphology and regional tectonics, offering a refined framework for understanding the geodynamic evolution of this exceptionally complex convergent boundary.

Abstract: On 8 February 2025, an Mw 7.6 strike-slip earthquake ruptured the Swan Islands Transform Fault in the northern Caribbean near its junction with the Mid-Cayman Spreading Center, providing an important offshore case for investigating rupture dynamics along oceanic transform faults. In this study, we jointly apply teleseismic high-frequency back-projection and low-frequency finite-fault full-waveform inversion to image the multi-scale spatiotemporal evolution of the rupture process. Back-projection results reveal a two-stage rupture characterized by an initial sub-shear propagation lasting approximately 20 s, followed by rapid acceleration to supershear velocities of ~5–6 km/s and westward propagation over ~80–100 km. Finite-fault inversion shows that coseismic slip is primarily concentrated within ~20 km west of the epicenter, with a peak slip of ~5.6 m and an overall rupture duration of ~40 s. Comparison between high-frequency radiation and low-frequency slip indicates that most seismic moment was released during the early slow rupture stage, whereas the later fast-propagating segment produced enhanced high-frequency energy but relatively small slip. These observations reveal a pronounced along-strike complimentary relationship between slip amplitude and rupture speed, suggesting a transition in rupture dynamics controlled by variations in fault strength, fracture energy, and/or geometric complexity. By combining high-frequency back-projection with low-frequency finite-fault inversion, we obtain a more complete view of the rupture process of offshore earthquakes, which helps clarify rupture propagation characteristics, including supershear behavior, along oceanic transform faults.

Abstract: Lava flows represent complex thermofluid phenomena in which surface cooling leads to the formation of a solidified surface layer. Understanding the influence of such a surface layer on fluid flow is an important issue in lava flow modeling, and it also shares essential characteristics with a wide range of engineering problems involving surface solidification. However, the role of plastic surface skin in controlling flow deceleration and stopping behavior has not been sufficiently clarified in existing models. In this study, two-dimensional smoothed particle hydrodynamics (SPH) simulations were conducted to investigate the influence of surface skin formation on lava flow dynamics. The temperature dependence of viscosity was introduced to reproduce a plastic surface skin. The skin was represented as a low-temperature, high-viscosity region. Comparisons with simulations without surface skin formation demonstrated that the surface skin exhibits a suppressive effect on the flow. This behavior was consistent with qualitative observations of flowing lava. It was also found that this surface skin caused the successive deceleration characteristic in Bingham fluids. As a result, both the flow velocity and the flowing distance are affected. These results suggest that accurate lava flow simulations require models that incorporate both surface skin effects and non-Newtonian behavior.

Abstract: In February 2024, the European Union published its Industrial Carbon Management Strategy, setting ambitious goals for Carbon Capture and Storage (CCS), Carbon Cap-ture and Utilisation (CCU), and related technologies. Industrial decarbonisation will require a mix of solutions, CCUS, electrification, hydrogen and hydrogen-derived fuels, and energy efficiency, all dependent on affordable clean energy. Although carbon management technologies could contribute substantially to climate targets, their de-ployment has been slowed by technical barriers and public concerns. Sotacarbo created a research centre dedicated to developing and testing carbon capture, utilisation, and storage technologies. Within this framework, the new Sotacarbo Fault Laboratory (SFL) was designed to investigate gas migration in faults and to test monitoring systems ca-pable of detecting potential short- and long-term CO₂ leakages. This paper presents a preliminary study, including seismic full-waveform simulations for time-lapse surveys before and after CO₂ injection, and a suite of geophysical methods used to characterise the Matzaccara fault within the Eocene Sulcis Basin. The results of the application of integrated geophysical methods supported the selection of a safe and suitable injec-tion-well location and demonstrated the value of these methods for detailed fault characterisation in CCUS applications.