Electrical resistivity tomography for geohazard assessment in West Lombok’s alluvial plain

Ground failure mechanism for deep tunnel in sandy cobble strata based on the cohesive zone element

As fragility and risk modeling techniques and computational capabilities evolve, complemented by moving toward more routine and systematic seismic risk assessment of all buildings and critical infrastructure, the authors pose a few critical questions to investigate how the U.S. Geological Survey (USGS) National Seismic Hazard Models (NSHMs) can be used and enhanced further to serve such issues. In this paper, we use three examples from multiple sectors to (1) identify the role of USGS NSHMs in evaluating seismic risks to critical infrastructure, (2) quantify potential impacts from NSHM enhancements (i.e., [i] hazard curves for the vertical component of ground motion, [ii] stochastic event sets, and [iii] maps of probabilistic ground failure hazards), and (3) clarify the feasibility of relevant NSHM improvements. We illuminate that NSHMs are commonly used in location‐specific performance assessments, whereas earthquake effects on critical infrastructure can be widespread across large geospatial regions. Further, we found that without the NSHM extensions considered here, risk can be severely underestimated, e.g., neglecting ground failure hazards can underestimate regional loss by a factor of two or more. Although many challenges remain, we developed example prototypes to clarify the feasibility of the NSHM extensions, which can facilitate improved management of risks to critical infrastructure.

On 6 February 2023, two destructive earthquakes (Mw 7.7 and Mw 7.6) struck the Pazarcık and Elbistan districts of Kahramanmaraş, causing widespread damage across 11 provinces in southern Türkiye near the Maraş Seismic Gap along the East Anatolian Fault System. Post-earthquake investigations indicate that the observed building damage resulted from the combined effects of strong seismic loading, structural deficiencies, and unfavorable local ground conditions. Therefore, soil liquefaction and earthquake-induced ground settlements are not considered the sole causes of structural collapse throughout the entire affected region; rather, their influence is evaluated in a site-specific manner, particularly in areas such as İskenderun and Adıyaman-Gölbaşı where soil conditions are highly prone to liquefaction. Field observations indicate that liquefaction-related deformations were concentrated in loose, saturated sandy and silty deposits with shallow groundwater levels. Soil samples from these zones were analyzed using SEM, EDX/EDAX, and XRD to characterize their microstructural and mineralogical properties, while strong-motion records from nearby stations were evaluated to relate seismic input to the observed ground failures. The results emphasize the necessity of site-specific geotechnical evaluations and integrated seismic risk assessments, avoiding generalized interpretations of damage mechanisms in large-scale earthquake events.

Gastric cancer remains a major global health burden, particularly in East Asia, yet early-detection programs are often limited by computational constraints, variable imaging quality, and uneven resource availability across clinical settings. Existing AI models for CT analysis frequently require GPU-accelerated infrastructure and offer limited transparency or reproducibility, reducing their suitability for deployment in low-resource hospitals. To address these gaps, we developed and publicly released Banana 0.9, an open-source, CPU-based medical imaging framework intended to support fully reproducible, CT-based gastric cancer screening workflows. Banana 0.9 serves as a proof-of-concept milestone toward a broader, cross-cancer screening platform emphasizing interpretability, accessibility, and transparent methodology. Banana 0.9 was implemented as a modular, GPU-free CT imaging pipeline using deterministic Hounsfield-unit (HU) rules for organ and region-of-interest segmentation, and a fully open-source architecture for reproducibility. The system accepts DICOM, NIfTI, and ZIP inputs, and includes optional YAML-configured biomarker simulations (TriOx) and conceptual clinical risk-factor modules. These components are exploratory and intended as proof-of-concept simulations rather than validated clinical predictors. An automatic dual-audience reporting component generates structured summaries for both clinicians and patients. Internal evaluations used 10 000 Monte Carlo simulations, incorporating literature-derived Helicobacter pylori prevalence estimates and imaging statistics from the TCGA-STAD dataset. To explore potential deployment variability, experiments were conducted under simulated "urban" (higher-quality imaging, complete metadata) and "rural" (lower resolution, partial metadata) screening conditions. For external assessment, we applied the pipeline to 773 independent CT scans from the AbdomenCT-1K TumorSubset. Because this dataset lacks segmentation ground truth, the experiment was used to evaluate cross-dataset reproducibility and stability, without retraining or parameter tuning, thus reflecting reproducibility rather than accuracy assessment. An anonymized English summary of the external validation process is provided in Supplementary File S1. All source code, configuration files, and example data are publicly available to support end-to-end transparency and reproducibility. Across 10 000 Monte Carlo simulations representing urban and rural screening conditions, Banana 0.9 produced a simulation-derived mean AUC of 0.87 (95% CI 0.84-0.90). Estimated computational demand was reduced by more than 80%, with model-based projections suggesting a ~ 60% decrease in average per-patient screening costs relative to conventional GPU-dependent workflows, an estimate based on assumptions regarding typical hardware pricing, device lifespan, and energy consumption. Simulated detection rates increased from 70% to 85% under "urban" conditions and from 65% to 80% under "rural" conditions. For external assessment, Banana 0.9 processed 773 independent CT scans from the AbdomenCT-1K TumorSubset with 100% successful execution and without retraining or parameter adjustment. Although this dataset does not provide segmentation ground truth, no instability or failure modes were observed relative to internal simulations, indicating reproducible operation across heterogeneous imaging domains. Banana 0.9 offers an open, transparent, and GPU-free imaging framework aimed at improving reproducibility and accessibility in gastric cancer screening workflows. Using internal Monte Carlo simulations and external execution on an independent CT dataset, the system demonstrated consistent and reproducible operation without retraining or parameter adjustment, providing preliminary evidence of stability across heterogeneous imaging conditions. While the present evaluation relies on simulated performance estimates and non-annotated external data, the modular architecture, openly available codebase, and low computational requirements position Banana 0.9 as a practical starting point for future extensions toward clinically validated, multi-cancer CT screening tools aligned with FAIR data principles and global health needs.

Crossing-fault tunnel is vulnerable especially when the fault dislocation happens. The propagation of fault rupture affects the deformation on ground surface and failure on underground structures and it is vital for crossing-fault tunnel to reveal dislocation mechanism with fault rupture propagation. Thus, based on different fault parameters such as width of fault fracture zone and fault dip, three experimental tests were carried out to obtain the propagation mechanism of fault rupture and its impact on ground deformation and failure of tunnel with a self-designed large-scaled model box. The test results firstly show that the fault parameters effect the pattern of fault rupture. Under the propagation of fault rupture, four sub-regions were identified on ground surface as stability region in footwall, coordination region, severe deformation region and stability region in hanging wall. The parameter influence from fault fracture zone will be sensitive for tunnel and the tunnel near fault fracture zone is most damaged. Typical damage types transversely can be divided into four categories according to the degree of damage and moderate damage or serious damage should be avoided as far as possible to guarantee the normal operation of the tunnel.

Structurally controlled rock instability is one of the most critical types of ground failure in underground excavations under low-stress conditions. Typical stability analysis approaches consider a series of simplifications related to the geometry of the rock discontinuities and the excavation. These methods cannot fully determine the probability of occurrence and size of wedges formed at the excavation walls, which is critical for quantifying the hazard associated with wedge failure in underground mines. This paper presents a comprehensive and systematic approach for assessing wedge formation and stability around underground mining excavations. The work considers the complexity of the structural regime using DFN modelling and the detailed 3D underground excavation profile obtained from surveying. The developed approach was successfully applied in an operating underground mine, enabling the estimation of the location and size of the most critical wedges and quantification of the risk associated with wedge formation. Determining the possible magnitude and location of formed wedges is invaluable information for designing drift geometry and rock reinforcement strategies. The DFN-based risk analysis was combined with economic metrics, providing a comprehensive risk analysis related to wedge failure at the underground mine. The developed approach contributes to optimizing ground support systems under low-stress conditions.

The seismic nature of the soil in urban spheres is very susceptible to seismic ground failures caused by intricate soil conditions, extensive development, and outdated construction methods. However, structural solutions have always played the most important role in seismic design; growing evidence points to the importance of geotechnical engineering in the development of earthquake-resilient urban infrastructure. In this paper, a synthesis of geotechnical methods of earthquake resilience is given based on the seismic hazard evaluation, mitigation of liquefaction, ground improvement, foundation, and soil structure interaction. The analyzed literature shows that seismic demand in urban regions may differ by 24 times depending on the specific conditions of the soils in various micro zones. Sites that contain Vs30 less than 180 m/s are always highly amplified on the ground and prone to liquefaction. The techniques of liquefaction mitigation are proven to be very effective. Densification methods reduce the settlement by 30-50 %, drainage systems achieve 40-70 % reduction of excess pore water pressure, and soil stabilization methods yield up to 60-80 % settlement reduction. Ground improvement techniques increase the soil stiffness in the range of 1.5-3.0 times, whereas pile-raft foundation systems minimize seismic settlement, 20-40 % as compared to a shallow foundation. The fact that soil structure interaction is considered changes the structural natural periods by 10-30% by an important factor in seismic response. The results point out that the site-specific geotechnical interventions will be necessary to minimize the seismic damage and enhance the post-earthquake performance. The research offers a technical foundation of how to incorporate geotechnical solutions in the urban seismic resilience planning and aids the wise choice of safer and more sustainable cities.

The 17 November 2023 MW 6.8 earthquake located offshore of Southern Mindanao, Philippines, triggered soil liquefaction along the lowlands of the Sarangani Peninsula. Detailed mapping, geomorphological interpretations, geophysical surveys, comparison with predictive models, and grain size analysis were conducted to obtain a comprehensive understanding of the earthquake parameters and subsurface conditions that permitted liquefaction. Soil liquefaction manifested as sediment and water vents, fissures, lateral spreads, and ground deformation, mainly along landforms with shallow groundwater levels such as river deltas, fills, floodplains, and beaches. In populated areas, ground failure due to liquefaction also damaged some buildings. All these impacts fall within the boundaries of the available liquefaction hazard maps for Sarangani Peninsula and the predictive empirical equations generated by various authors. Simulated peak ground acceleration values also indicate that sufficient ground shaking was generated for the soil to liquefy. Refraction microtremor (ReMi) surveys reveal shear wave velocities ranging from 121 to 215 m/s, which infer the presence of soft and stiff soils beneath the surface, promoting the sites’ potential to liquefy. Grain size analyses of sediment ejecta confirm the presence of these liquefiable sediments from the subsurface, with grain sizes ranging from silt to medium sand. The results of three-component microtremor (3CMt) surveys also show varying sediment thicknesses, which are consistent with the thickness of soft sediment layers inferred by ReMi surveys. The information resulting from this study may be useful for researchers, planners, and engineers for liquefaction hazard assessment and mitigation, especially in the Sarangani Peninsula.

Liquefaction is a severe earthquake-induced ground failure that reduces soil strength and foundation stability. This study examined the influence of fines content (FC) on soil liquefaction behaviour through field case histories and laboratory tests. According to many earthquake case histories of standard penetration test (SPT) blow counts, FC has an important significant effect on the liquefaction behaviour of soil. The SPT blow count was determined through 114 cyclic triaxial tests (CTT) and 37 cyclic hollow cylinder tests (CHCT) on Monterey Sand and Leyden Clay with varying FC (0%-45%), a method named "Conversion of Laboratory Test Results to SPT N-Blow Count" (LTRC-SPT) was developed to convert laboratory results into equivalent SPT blow counts. Results show that pure sand has the highest critical SPT N-value, which decreases as FC increases, but rises again after a threshold of about 25%. This highlights the special sensitivity of soils with 20%-30% FC in liquefaction analysis. Utilizing the results from CTT and CHCT tests, a back propagation neural network (BPNN) was employed to forecast SPT blow counts. This BPNN model demonstrates excellent accuracy, achieving a mean absolute percentage error (MAPE) of just 1.95%. Additionally, it aids engineers in gaining a deeper insight into the liquefaction potential of soil samples with varying fines content.

Many immersed tunnels are constructed in alluvial formations within earthquake-prone regions, making seismic resistance a critical aspect of their safety design. During an earthquake, tunnel displacements can lead to slippage between the tunnel and surrounding soil and may be further amplified by liquefaction. This phenomenon can cause severe structural damage, including tunnel flotation. This paper examines the seismic performance of immersed tunnels, starting with an overview of the deformation mechanisms affecting tunnels, including those induced by ground shaking and failure. Given its significance in large foundation deformations and its impact on tunnel integrity, liquefaction is analyzed alongside potential mitigation strategies. The seismic design process for immersed tunnels is discussed in detail, covering analytical approaches, numerical modeling techniques (such as finite element and finite difference methods), and physical modeling. Real-world examples are provided to illustrate key concepts. Finally, this paper summarizes the core factors influencing the seismic response of immersed tunnels and highlights future research directions to enhance their resilience in seismic environments.

Pipeline exfiltration from damaged water-supply systems frequently causes soil erosion and ground subsidence, which jeopardizes the safety of pedestrians and vehicles and even causes casualties. Despite the severe consequences, it is difficult for engineers to give reliable assessments of pipeline exfiltration hazards. In this study, erosion processes were explored using model tests and coupled computational fluid dynamics–discrete element method (CFD-DEM) simulations. It was discovered that the erosion zone can be divided into two zones—the exfiltration zone and the seepage diffusion zone. When water pressure reached 2.412 × 10−2 MPa, local porosity approached 1.0, indicating there were no soil particles remaining. As pipeline pressure increased from 2.122 × 10−3 MPa to 2.412 × 10−2 MPa, ground failure transitioned from downward settlement to upward bulge, and the ground failure duration of the fractured prototype pipe was reduced by 22–28% (from 125 s to 98 s), with a standard deviation of less than 5. The established exponential decay model (v(t)=v0e(−αt),R2>0.89) enabled prediction of erosion duration. Based on the erosion height curve, the erosion duration and erosion area in similar engineering environments can be estimated, providing a reference for evaluating the risk of ground collapse due to pipe exfiltration.

Summary Flooding of abandoned excavation mines implies significant changes in the hydromechanic rock behavior often associated with instantaneous rock instabilities which cause underground and ground failure and collapses, sometimes (but not always) accompanied by induced seismicity. The permanent modification of the hydrogeological setting may, in certain cases, also induce long-term seismic activities persistent over several years. The governing hydromechanic triggering mechanisms are poorly understood in these cases what bares challenges in related seismic hazard and risk assessment. In this study, we provide new insights into this poorly explored field of fluid induced seismicity, by investigating the long-lasting (> 10 years) swarm activity induced by the flooding of an abandoned coal mine at Gardanne in Southern France. The strongest events of the activity have comparatively small magnitudes (Mw < 2) but are felt by the local population due to their shallow source depth (< 1 km). Thanks to full waveform based source analysis we show that the swarm is associated with the permanent activation of preexisting faults situated below the flooded mining voids which act as a very high-capacity anthropogenic reservoir and aquifer. We further show that mine water level changes caused by either natural or anthropogenic driving forces cause seismic triggering which involves direct pore-pressure as well as poroelastic effects. These findings provide constraints for adequate guidelines for safe mine water level management and seismic risk mitigation.

The study of slope stability in the Sartka region, a significant tourist destination in the Dukan district of the Kurdistan Region of Iraq, is crucial due to its ongoing urban expansion. The landslide rock falls, and ground failures have considerably affected family camps, tourist roads, and recently built residential areas on slopes affected by cutting and filling operations, exposing them to landslide risks. This study focuses on assessing the risk of landslides in mountainous regions using the Landslide Possibility Index method. The method assesses factors that affect slope stability and identifies areas of risk. It improves predictions about cut slopes in mountainous roads. The study identifies the predominant type of landslides and classifies sites based on factors like slope angle, fracture degree, weathering degree, discontinuity gradient, spacing, orientation of discontinuities, vegetation cover, water infiltration, and previous landslides. In addition to the magnitude and range of the dangers that slopes are subject to, five stations were selected, information was gathered, and ten LPI system parameters were measured in the field. The results indicate varying degrees of risk for different sections, ranging from moderate to very high. The slopes in the study area are characterized by a high degree of fracturing and weathering, with very minimal spacing between the joints, and a favorable orientation of these joints in relation to the bedding plane dip. as well as the marl layers of the Kometan and Tanjero formations increase the vulnerability of rock slopes to weathering and erosion, leading to more slope failures. The research highlights the need for preventative measures and engineering solutions to protect structures and ensure public safety in the area.

This paper presents a numerical investigation into the theoretical safety criteria for the toppling of cranes and pile drivers by providing sample calculations and expanding on previously published theoretical work, in which the fundamental elements, such as the structural model, the classification of toppling modes, etc., are developed. It is believed that the frequent occurrences of crane and pile driver toppling are closely related to structural instability within their toppling mechanisms. The conventional evaluation method for toppling stability, which is based on the overturning moment approach, may not sufficiently address the mechanisms of toppling on soft ground. In fact, many toppling accidents show signs of inadequate ground strength, such as ground failure. This issue likely involves not only a lack of ground strength to withstand the bearing pressure from crawlers or outriggers but also insufficient deformation performance (stiffness) of the ground. In structural stability theory, an important factor in assessing the required ground stiffness is the height of the applied load. Conventional toppling stability assessments assume that if the overturning moment is the same, the stability will also be the same. However, from the perspective of structural stability theory, toppling can occur even when the overturning moment is zero in extreme cases with weak ground stiffness and large load height. This study aims to look for the influence on the toppling mechanism by presenting sample calculations for a simple analytical model under various operational conditions—including load height, ground stiffness, and working radius—to better define the criteria for toppling. Received: 14 May 2025 | Revised: 17 July 2025 | Accepted: 9 September 2025 Conflicts of Interest The authors declare that they have no conflicts of interest to this work. Data Availability Statement Data are available on request from the corresponding author upon reasonable request. Author Contribution Statement Shouji Toma: Conceptualization, Methodology, Formal analysis, Investigation, Data curation, Writing - original draft, Writing - review & editing, Visualization. Wai Fah Chen: Validation, Supervision, Project administration.

In February 2023, a devastating earthquake sequence struck southern Tü rkiye, marking one of the most destructive seismic disasters in the region’s modern history. The MW 7.8 mainshock, followed by several large aftershocks, produced catastrophic consequences, including extensive structural collapse, widespread ground failure, and severe liquefaction that collectively left millions displaced and caused tens of thousands of fatalities. The extraordinary intensity of the shaking was reflected in the recorded ground motion parameters, particularly spectral accelerations, which significantly exceeded the design thresholds stipulated in the Turkish Earthquake Code (2018). Such exceedances provide critical insights into the limitations of existing design provisions and underscore the urgent need to revisit seismic hazard and risk assessments. Field investigations documented severe manifestations of liquefaction, lateral spreading, and ground subsidence, especially in Holocene sedimentary basins where loose, water‑saturated soils amplified shaking and induced ground instability. Structural surveys further revealed recurring vulnerabilities in the built environment, including weak or soft‑story configurations, non‑ductile reinforcement, and inadequate foundation practices, all of which amplified damage levels. The disaster highlights the urgent need for stricter enforcement of seismic building codes, the integration of resilient design methodologies, and the deployment of technologies such as base isolation systems and energy‑dissipating devices to enhance structural safety. In addition, systematic performance audits and proactive urban planning are recommended to mitigate similar future catastrophes. This study integrates geological evidence with engineering perspectives, offering targeted strategies to strengthen earthquake preparedness and foster long‑term urban resilience across Tü rkiye’s high‑risk seismic zones.

Abstract We present a method to update the geospatial liquefaction model used by the U.S. Geological Survey’s near-real-time ground failure product with subsurface geotechnical data. The geospatial model estimates liquefaction probability from peak ground velocity (via ShakeMap) and geospatial susceptibility proxies. In many regions, additional information relevant to constraining liquefaction likelihood is also available, including surface geology maps and subsurface geotechnical measurements. There is currently no mechanism to use these data in the ground failure product liquefaction model, even though these data could provide more precise constraints on spatial variations in the lithologic character of the soil (surface geology) and direct measurements of the subsurface mechanical properties that affect liquefaction occurrence and severity (geotechnical measurements). In this study, we develop a method to integrate these data with the geospatial model and assess how these data can improve regional-scale predictions. We develop a Bayesian updating framework and apply it to the 1989 magnitude 6.9 Loma Prieta, California, earthquake, for which mapped observations are available to evaluate performance. We constrain the Bayesian framework with 373 Northern California cone penetration tests and liquefaction susceptibility classes based on the mapped surface geology. This Bayesian model incorporates geotechnical information into the geospatial model and more accurately predicts liquefaction occurrences than the geospatial model, while sacrificing less accuracy in terms of predicting the absence of liquefaction than the geotechnical model. In future applications, this approach could be adapted to update other geospatial models using locally available subsurface data.

ABSTRACT The devastating 7.8 Mw seismic event that struck Nepal on April 25, 2015, led to extensive structural collapse and loss of life due to severe seismically induced liquefaction activity. The surrounding Tarai regions also experience the devastating effects of these cataclysmic catastrophes. Being located in the Tarai area near the seismically active Nepal Himalayan belt. Gorakhpur city, one of the biggest and fastest-growing, densely populated cities in eastern Uttar Pradesh (UP), was taken up for a standard penetration test (SPT)-based assessment of liquefaction potential. Field research and geotechnical analysis revealed the city’s susceptibility to earthquake-induced liquefaction and ground failure, posing significant risks to both life and property. This study aims to present the findings of the liquefaction susceptibility study in Gorakhpur city and its suburbs through safety factors and the liquefaction potential index (LPI). Using data from 30 boreholes, including ground acceleration from the 7.8M Nepal-Gorkha earthquake, SPT-N160 values, and groundwater table depth, the assessment indicates a high to very high seismic liquefaction potential (>5 LPI) in and around Gorakhpur city. Depth-wise analysis of boreholes identified six patterns of liquefiable and non-liquefiable layers up to 10.5 m deep. The study highlights a considerable portion of the city as prone to seismic liquefaction during strong earthquakes, attributed to shallow groundwater tables (2–9 m below ground level) and liquefiable sediment layers within 10 m depth, mainly consisting of fluvial, fine sand, and silt deposits. Understanding the severity and location of seismic liquefaction risks is crucial for urban planners and geotechnical engineers to develop infrastructure resilient to liquefaction-induced damage during earthquakes. By identifying vulnerable areas and implementing appropriate mitigation measures, cities like Gorakhpur can better prepare for and withstand future seismic events, ultimately reducing the impact on lives and property.

In 2019, a series of earthquakes struck the northern sub-Himalayan region of Pakistan, with the Mirpur earthquake triggering extensive coseismic liquefaction-induced surface deformations, such as sand blows, ground failure, and lateral spreading along the upper Jhelum Canal (UJC). A total of thirty-two vertical electrical sounding (VES) sites were acquired to investigate the deeper aquifer system in the region. An electrical resistivity tomography (ERT) survey was conducted along the canal to comprehensively delineate the subsurface conditions associated with the coseismic liquefaction phenomenon in the epicentral region. To address the water quality after the earthquakes, physiochemical analysis was also performed on twenty-four water samples collected from the tube wells and shallow water wells across the study area. The VES data reveals that the lithological units consist of thick layers of sandy clay, sand, and sand with gravel. The iso-resistivity map and hydrochemical analysis reflects fresh groundwater potential at a depth of about 100m. The ERT profiles identified a low resistivity (<10Ωm) saturated layer of clay that is about 20m thick. This saturated layer records the rise in groundwater level and contributes to liquefaction and land subsidence during an earthquake. The higher values of turbidity in shallow water samples document deterioration of water quality due to multiple earthquake tremors. The sandy aquifer units present at deeper levels are highly recommended for drinking purposes and domestic usage.

Abstract Rendani Airport, the main airport in the Manokwari area of West Papua, Indonesia, is situated in a region with high earthquake activity and flat lowlands, making it vulnerable to liquefaction threats. This study aims to determine the risk of ground failure due to liquefaction using the Liquefaction Risk Index (LRI) and its severity using the Liquefaction Severity Index (LSI). Standard Penetration Test (SPT) data were collected from two locations, and Peak Ground Acceleration (PGA) values were obtained using a nonlinear soil model provided by DEEP SOIL V7 software based on the most relevant ground motion from the Pacific Earthquake Engineering Research Center (PEER) database. The PGA values obtained were between 0.321 - 0.420 g in each layer up to a depth of 50 meters. The calculation shows liquefaction at 5 - 10 meters depth at each bore location. Based on the LRI and LSI values, BH-01, with a value of 39.683, is included in the very high-risk criteria and medium liquefaction severity, while BH-02, with a value of 32.987 is included in the very high-risk criteria and low severity. This study shows the potential for liquefaction hazards in the area, highlighting the importance of conducting further investigations with comprehensive data for access road development plans in the airport.