Abstract Background The reliable earthquake magnitude estimation is a critical component of earthquake early warning (EEW) systems. Conventional P-wave–based amplitude parameters, such as peak vertical displacement ( P d ), are widely used but often suffer from saturation and instability, particularly for larger earthquakes and when low-cost MEMS sensors are employed. The cumulative absolute absement (CAA), a time-integrated displacement parameter, has recently emerged as a promising alternative for improving early magnitude estimation. Methods This study analyzes strong-motion records from the dense P-Alert low-cost MEMS sensor network in Taiwan to evaluate the performance of CAA for earthquake magnitude estimation. CAA values were computed using P-wave windows ranging from 1 to 5 s after P-wave arrival, using stations within a hypocentral distance of 70 km as well as the nearest six stations. Empirical regression relations were developed to estimate magnitude from CAA and P d , and the resulting magnitudes were compared with the catalog moment magnitude ( M w ). A generalized moment magnitude ( M wg ) was additionally used to assess magnitude-scale consistency and bias in small to moderate earthquakes. Results The standard deviation between CAA-derived magnitude ( M caa ) and M w decreases systematically with increasing window length, from ±0.383 for a 3 s window to ±0.333 for a 5 s window when using all stations within 70 km. In contrast, P d -derived magnitudes ( M pd ) show larger deviations, reducing from ±0.504 (3 s) to ±0.398 (5 s). Reliable magnitude estimates are also achieved using only the nearest six stations, with standard deviations of ±0.341 (CAA) and ±0.460 ( P d ) for the 5 s window. CAA exhibits a stable scaling with earthquake magnitude, while P d tends to stagnate and underestimate events approaching M w 7.0. Magnitude scale consistency tests using M wg confirm the robustness of the proposed CAA relations after correcting for M w bias. Conclusions The results demonstrate that CAA provides a more stable and reliable early magnitude estimator than P d , particularly for low-cost MEMS sensor networks and limited station availability. The reduced dispersion, lower saturation tendency, and robustness across different window lengths highlight the strong potential of CAA for operational on-site EEW systems using dense, cost-effective seismic networks.

Abstract Background The slope deformation of the Eggerbach slope above the Gradenbach river in Carinthia, Austria, has been monitored since 1966 following a critical acceleration event that caused damming and erosion of the Gradenbach river, resulting in devastating floods and debris flows in Putschall village. This study analyses several decades of comprehensive monitoring data, including time series from continuous, non-continuous GNSS stations (2009–2023), analog wire extensometer measurements (1980–present), borehole water level recordings, and meteorological data from the SPARTACUS v. 2.1 and SNOWGRID-CL gridded climate datasets. Distinct displacement patterns observed across four GNSS stations necessitated revision of the previously assumed single-domain geological model. Results Engineering geological analysis reveals that the Eggerbach slope constitutes a rock compound slide comprising four kinematically distinct domains: two upper translational slides (controlled by foliation-parallel surfaces at 60–80 m depth) and two lower rotational slides (controlled by fault plane ruptures along the Mölltal fault system at 120–140 m depth). Movement vector analysis shows systematic \alpha-angle progression from 14° to 34° across domains, reflecting the transition from compression-dominated vertical zones to rejoin to extension-dominated translational sliding in the upper slope. Annual horizontal displacements range from 4.11 to 6.74 m across domains since 2009, with significant velocity increases in 2018, 2020, and 2021 (peak values 0.54–1.15 m/yr) that deviate substantially from the 40-year baseline trend (0.04 to 0.19 m/yr). Statistical analysis establishes snowmelt—not precipitation—as the primary trigger for acceleration events, with cross-correlation analysis revealing r = 0.67 (p < 0.001) at 15–22 day lags between snow water equivalent (SWE) decreases and velocity peaks. Spring snowmelt (April–May) accounts for 89% of total annual displacement, with SWE reductions >150 mm within 30-day periods triggering velocity increases exceeding 2× background rates in 73% of analyzed events. Machine learning models (Support Vector Machines, Random Forest, XGBoost) achieved 78–85% variance explanation for velocity prediction and successfully forecasted 2018–2021 acceleration events despite training only on lower-velocity pre-2010 data. Feature importance analysis quantifies that borehole water levels (42%) and SWE (25%) dominate displacement controls, while precipitation contributes marginally (8%), enabling operational 15–30 day velocity forecasting for early warning applications. Discussion and Conclusion A critical temporal anomaly—where comparable SWE levels in 1991–1993 versus 2018–2021 produced 3–8× different velocity responses—suggests potential degradation of drainage infrastructure installed in the 1970s through mechanical shearing, calcareous precipitation in carbonate-rich domains, or pathway blockage. However, this hypothesis requires validation through targeted drainage system investigation. The stability number (Ns = 1.08 >> 0.25) calculated from uniaxial compressive strength analysis indicates ductile plastic behavior, suggesting gradual rather than catastrophic failure potential provided consolidation barriers function and toe-erosion is prevented. The lower rotational domains function as compressional buttresses absorbing gravitational loading from upper translational masses, creating mechanical coupling where system stability depends critically on maintaining toe confinement.

Abstract Introduction Debris flows are climate change-driven geohazards that pose a significant threat to life and the built environment. These flows are unconfined, in which the water-laden mass comprising of soil, gravel, boulders, and trees surges down steep hill slopes and channelises into streams, trapping everything that encounters them. These hazardous flows impact the engineering and defence structures, transportation systems, and the environment. State of Knowledge Various researchers have performed numerous laboratory-to-field scale experiments to understand debris flow's dynamic morphological and rheological properties. The state-of-the-art approach to evaluating the effect of multiple factors, such as water content, pore water pressure, grain size distribution, topography, solid volume fraction, and basal friction parameters on the initiation mechanism, dynamics, and morphology, has evolved rapidly in the past few decades. Objective The present paper discusses the progress in the identification of rheological and morphological characteristics of the debris flow and the advancement in debris flow experimentation. Approach and Scope This review will help the readers get a consolidated overview of the recent advancements in debris flow experiments. The study complements the previous studies by identifying the latest developments in debris flow experiments, such as the effects of material and geometric parameters on flow dynamics, mechanisms of evolution of excess pore water pressure in saturated and unsaturated bed conditions, entrainment mechanisms, and the classification of experiments based on the type and size of experimentation. Discussion and Relevance The characteristics of debris flow are also discussed based on different phases in debris flows, such as the initiation phase, dynamic phase, morphological characteristics, and impact on the built environment.

Abstract Background Initial shear stress and loading rate are two critical factors influencing soil mechanical behavior. Their coupled effects, however, remain insufficiently understood, particularly in terms of strength evolution and deformation mechanisms. Objective This study aims to investigate the coupling effects of loading rate and initial shear stress on soil shear behavior and to clarify their influence on strength characteristics and energy dissipation. Method A series of laboratory shear tests were conducted under varying initial shear stress levels and loading rates. Stress–strain responses, strength parameters, and energy components were systematically analyzed to quantify their coupled effects. Result The results indicate that both loading rate and initial shear stress significantly affect soil shear strength and deformation behavior. Increasing loading rate enhances peak strength, while initial shear stress alters stiffness and failure characteristics. Distinct energy dissipation patterns were observed under different coupled conditions. Conclusion The coupled influence of loading rate and initial shear stress plays a dominant role in governing soil shear behavior. These findings provide new insights into soil strength mechanisms and offer a theoretical basis for geotechnical design under complex stress and loading conditions.

Abstract Background Following the impoundment of the Three Gorges Reservoir, deposit-layer landslides in the reservoir basin have experienced cyclic deformation under the combined influence of seasonal precipitation and periodic water-level operations. The deformation amplitude accumulates annually, continuously bringing uncertainty to the safety of the reservoir basin. Purpose This study takes the Tanjiahe landslide (a typical feature in the Three Gorges Reservoir region) as the research object. By integrating its recent daily displacement measurements, daily rainfall data, and reservoir water-level observations, this research aims to establish a deep learning-based prediction model to forecast the landslide’s long-term deformation trends. Specifically, the aggregated displacement time series is segmented into a trend term and a cyclic term, so as to separately characterize the landslide’s long-term evolution and periodic dynamic behavior. Methods First, Grey Relational Analysis (GRA) and Pearson’s correlation analysis are used to identify the dominant influencing factors of the Tanjiahe landslide (including antecedent rainfall, reservoir water-level variation characteristics, and past displacement increments) as input features. Then, considering the timeseries nature of monitoring data and limited sample size constraints, a Long Short-Term Memory (LSTM) network is developed to predict the landslide’s cyclic displacement, while the trend component is modeled via Support Vector Machine (SVM) regression. Results The results indicate that the LSTM method significantly outperforms in depicting the complex nonlinear time-dependent features of landslide deformation; the SVM method stably captures the aggregate deformation trajectory and shows strong performance in low-frequency trend regression. Additionally, Rescaled Range (R/S) analysis of observed versus predicted sequences reveals significant long-term persistence in the Tanjiahe landslide’s deformation evolution at its current phase. Conclusion This study demonstrates that the combined LSTM-SVM model can effectively predict the Tanjiahe landslide’s long-term deformation. The identified long-term persistence of deformation provides a basis for long-term risk assessment and early warning of this landslide.

Abstract Background The safe disposal of radioactive waste requires meticulously engineered containment systems to prevent the release of hazardous radionuclides into the environment and protect human populations. A key component of these systems is the liner, particularly in multilayer configurations designed to enhance containment efficiency. Clay liners, especially those incorporating bentonite, serve as critical barriers by immobilizing contaminants and restricting leachate migration. This study evaluates the suitability of bentonite as a barrier liner material for the sequestration of cesium (Cs) and cobalt (Co) radionuclides through a comprehensive analysis integrating experimental sorption studies, kinetic modeling, and statistical physics approaches. Results Batch sorption experiments were performed to quantify Cs and Co uptake by bentonite under varying conditions of pH, temperature, and initial ion concentration. Fractal kinetic models were employed to describe time-dependent sorption behavior, emphasizing the role of fractal-like surface properties of bentonite’s on sorption kinetics. The experimental saturation capacities for Cs were determined to be 8.01, 8.35, and 8.98 mmol/kg, while those for Co were 8.86, 9.27, and 9.61 mmol/kg at 298, 313, and 333 K, respectively. Statistical physics modeling provided insights into the equilibrium sorption mechanisms, revealing multi-molecular sorption characterized by a steric parameter n > 1 in the best-fitted monolayer model with two energy sites (R2 > 0.996). This suggests that Cs+ and Co2+ ions adopt a vertical orientation at two distinct active sites, with their interactions primarily governed by van der Waals forces, hydrogen bonding, and electrostatic attractions. The robustness of bentonite for radionuclide sorption was further validated by fractal-like pseudo-second-order kinetic modeling (R2 > 0.96), confirming the presence of energetic heterogeneity. Additionally, hydrodynamic dispersion coefficients were estimated using the Brigham model, offering valuable insights into solute transport dynamics. A preliminary assessment of radionuclide migration through the bentonite liner was conducted via analytical modeling, wherein the Ogata and Banks solution, coupled with nonlinear fitting analysis, reliably predicted ion transport trends. Conclusion These findings collectively reinforce the feasibility of bentonite as an effective liner material for radioactive waste containment, demonstrating its high sorption capacity and transport-limiting characteristics essential for long-term environmental protection.

BackgroundLandslides are a major and recurring hazard in the folded Tertiary sedimentary rock units of Southeastern Bangladesh. The mechanical strength and stability of these rocks are strongly influenced by their mineralogical composition and geochemical alteration, which can affect their susceptibility to weathering and collapse. However, the role of these factors in triggering landslides remains poorly understood.ObjectiveThis research addresses this gap by linking rock weathering intensity and clay mineral composition to landslide mechanisms in the outcropped Tertiary Formations in the Rangamati region.MethodsDetailed geological field work has been conducted on four major exposed Tertiary Formations: Dupi Tila Formation, Tipam Sandstone Formation, Boka Bil Formation, and Bhuban Formation. A comprehensive analysis of 30 landslides is carried out to evaluate the geological influence, with 22 samples (both fresh and weathered) examined using X-ray Diffraction (XRD), X-ray Fluorescence (XRF), and Scanning Electron Microscope (SEM) techniques to determine clay content and the extent of weathering. Shale percentages are estimated from outcrops as well as from wireline logs using empirical equations.ResultsThe Bhuban Formation exhibits the highest shale content, followed by the Boka bil, Dupi Tila, and Tipam Sandstone formations. Illite is identified as the dominant clay type and they are more prevalent in the older formations. Smectite is also present in varying proportions contributing significantly to landslide occurrences through its expansive properties. The Upper Marine Shale in Bokabil Formation contains the most smectite, followed by the Dupi Tila and Bhuban formations. The degree of weathering is evaluated through field observations and oxide analysis, with average Chemical Index of Alteration (CIA) values exceeding 75, indicating intense weathering in all formations, as clearly reflected in the outcrops. Four primary types of landslides: flow, fall, slide, and complex—are identified across all formations in varying proportions. Flow is predominant in formations dominated by single rock type, such as the Bhuban and Tipam Sandstone formations, while slides are more common in formations with alternating layers of sandstone and shale, such as the Boka bil and Dupi Tila formations.ConclusionThe findings highlight that higher shale volume, clay content, and CIA values significantly elevate the landslide susceptibility of geological formations, especially when these factors are compounded by primary triggers like intense rainfall and human-induced slope modifications.

BackgroundFaulting induced by earthquakes and its analysis are of great importance for areas with high probability of earthquakes. However, there has been no particularly effective methods to evaluate the damage and applicable solutions for recovery. In this paper, the damage from Türkiye earthquakes is investigated by authors, which has important theoretical significance and practical value. On 6 February, 2023, two successive earthquakes with magnitudes (Mw) of 7.8 (called Pazarcık earthquake) and 7.6 (Ekinözü earthquake) occurred in the south-eastern part of Türkiye. The total length of the surface ruptures was more than 500 km long and resulted in striations reflecting the sinistral faulting and extensive ground deformations. In this study, the authors present the outcomes of the investigations on the surface ruptures, their characteristics, stress field associated with both earthquakes, shear strength property of fault segments and the damaging effects on various structures and made some recommendations with the purpose of how to build structures in active fault zones and decrease the negative effects of faulting on structures.ResultsBesides summarizing the main characteristics of the world-shaking Kahramanmaraş earthquake doublet in southeast Türkiye in 2023, this study described the main features of the surface ruptures, their relation to the inferred crustal stresses in Türkiye, and the damaging effects on the major engineering structures. The observations and inferences are of great significance for understanding the causes of earthquakes and future seismic risk assessment. Various laboratory experiments were performed on the samples of fault gouge gathered from the sites of surface ruptures and these experimental results provided very valuable quantitative information on the constitutive models of the fault zones. The observations clearly showed that it is almost impossible to prevent damage on structures due to surface ruptures, if certain engineering principles such as increasing higher ductility, lowering gravitational center and/or the implementations of raft foundations are followed.ConclusionsThe stress state inferences obtained from the striation of the fault surface ruptures as well as from the focal plane solutions are expected to be useful to evaluate the regional stress state of the earthquake region. Assessments indicated that the stress states in Arabian plate and Anadolu platelet are different from each other. However, in-situ direct stress measurement techniques would be quite useful to validate the stress state inferred in this study. The laboratory experiments on samples gathered from the fault outcrops of the earthquakes using direct shear tests, stick-slip tests as well as conventional tensile, compressive and triaxial tests provided the quantitative values for the parameters of constitutive laws for fault zones, which can be utilized in the numerical simulation of earthquakes. If a fault break happens to be just passing underneath the structures, it is almost impossible for mankind to prevent the damage to structures. However, the authors made some recommendations to reduce the negative effects of fault ruptures on structures. These recommendations are such that the structures should be built as ductile and redundant structures with lower center of gravity and raft foundations. Dam construction should be on active faults should be avoided. If they are to be built for whatever reason, they should be of rock-fill type. As tubular structures and tunnels would be generally subjected forced displacement field, it is recommended to utilize flexible joints, segmented and enlargement to deal such displacement fields.

BackgroundRockfalls pose a serious threat along the main road network, representing a major hazard in mountainous territory and causing damage and victims. Currently, susceptibility mapping represents a starting point to identify areas more susceptible to rockfall occurrence, a key approach in land use planning and risk management. Despite the extensive use of these maps by decision makers and administrators, the usability of such maps over time and their reliability represent a poorly discussed and examined feature.MethodsHere, we proposed a-posteriori analysis of a three-year-old rockfall susceptibility map, generated along the main road network of the Aosta Valley, an alpine region of north-western Italy. To verify map consistency over time, we implemented a dual-analysis in GIS-environment and by text mining, to respectively analyse the geocoded data and textual information derivable from the regional landslide inventory. The first one allowed us to extract rockfall events occurred after the susceptibility map generation. By this way, we operated to spatially and temporally verify the map consistency. Jointly, the textual information reported in the Event Description Form, linked to each geocoded event, are being exploited. This allowed us to derive relevant information about occurred damage and their degree, presence of protective measures or secondary roads, i.e. involvement of, farm or forestry, road.ResultsThe implemented approach allowed us to prove the quality of the previous map in terms of reliability, robustness and degree of fitting respect to the succession of rockfall occurrence over time. After only three years as many as 198 rockfall events have been occurred and collected since the map was generated. Particularly, 80% of rockfall fit with “high” and “very high” susceptibility classes, and pointed out large involvement of main roads in rockfall occurrence, representing the most affected target with damage to road pavement and vehicles, as well as a relevant involvement of existing rockfall barriers and of the dense network of forestry roads and footpaths that characterize this alpine region.ResultsThe proposed approach representing a starting point in landslide susceptibility map verification and usability as valid instrument for a reliable land planning.