Infrastructure failure due to soil liquefaction has been repeatedly observed in past megathrust earthquakes, causing significant material and structural functionality losses. In most seismic regions, soil liquefaction potential is assessed using updated versions of the cyclic-stress-based simplified procedure initially proposed by Seed and Idriss in 1971. However, the application of these procedures to large-magnitude (Mw > 7.5) subduction earthquakes has shown discrepancies between forward predictions and field observations, particularly regarding liquefaction triggering and manifestation. This paper proposes an alternative model to assess soil liquefaction due to large-magnitude subduction earthquakes based on excess pore water pressure ratios and shear deformations. The triggering criteria are based on the peak values of excess pore pressure ratio and shear strain anticipated within the critical, potentially liquefiable soil layer. The model considers liquefiable layer thickness and relative density, along with input motion's Cumulative Absolute Velocity (CAV), as the main predictors of soil liquefaction. To this end, a numerical model was first developed and validated against results from a dynamic centrifuge test simulating free-field conditions. The calibrated numerical model was then used to perform a numerical parametric study to identify the trends and key predictors of liquefaction in layered soil deposits subjected to large-magnitude subduction earthquakes. Finally, a simplified probabilistic procedure, validated against available case histories, was developed to estimate the probabilities of full, marginal, and no liquefaction occurrence within each critical layer.

Landslide volume plays a pivotal role in controlling landslide movement and potential damage. Although rainfall is widely recognized as one of the most important factors underlying landslide occurrence worldwide, its impact on landslide volume has been investigated only for individual landslide types. In this study, we show that rainfall characteristics and magnitude control the volume produced by both shallow and deep-seated landslides. A total of ten shallow and deep-seated landslides in Japan were compiled with volume, occurrence time, and rainfall data. Rainfall characteristics that triggered landslides were identified using the Soil Water Index and the threelayer tank model, which is a simple runoff model, and magnitude was quantified based on lag time. A strong positive correlation was found between lag time and landslide volume, indicating that landslide volume increases with increasing magnitude of rainfall to induce landslides. This study is the first attempt to suggest a relationship between rainfall magnitude and the volume produced by shallow and deep-seated landslides systematically and will promote the development of landslide risk management strategies.

To achieve the loading of the stress path of hard rock, the spherical discrete element model (DEM) and the new flexible membrane technology were utilized to realize the transient loading of three principal stresses with arbitrary magnitudes and orientations. Furthermore, based on the deep tunnel of China Jinping Underground Laboratory II (CJPL-II), the deformation and fracture evolution characteristics of deep hard rock induced by excavation stress path were analyzed, and the mechanisms of transient loading-unloading and stress rotation-induced fractures were revealed from a mesoscopic perspective. The results indicated that the stress-strain curve exhibits different trends and degrees of sudden changes when subjected to transient changes in principal stress, accompanied by sudden changes in strain rate. Stress rotation induces spatially directional deformation, resulting in fractures of different degrees and orientations, and increasing the degree of deformation anisotropy. The correlation between the degree of induced fracture and the unloading magnitude of minimum principal stress, as well as its initial level is significant and positive. The process of mechanical response during transient unloading exhibits clear nonlinearity and directivity. After transient unloading, both the minimum principal stress and minimum principal strain rate decrease sharply and then tend to stabilize. This occurs from the edge to the interior and from the direction of the minimum principal stress to the direction of the maximum principal stress on the epsilon 1-epsilon 3 1-epsilon 3 plane. Transient unloading will induce a tensile stress wave. The ability to induce fractures due to changes in principal stress magnitude, orientation and rotation paths gradually increases. The analysis indicates a positive correlation between the abrupt change amplitude of strain rate and the maximum unloading magnitude, which is determined by the magnitude and rotation of principal stress. A high tensile strain rate is more likely to induce fractures under low minimum principal stress. (c) 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

The influence of thermal damage on macroscopic and microscopic characteristics of different rocks has received much attention in the field of rock engineering. When the rocks are subjected to thermal treatment, the change of macroscopic characteristics and evolution of micro-structure would be induced, ultimately resulting in different degrees of thermal damage in rocks. To better understand the thermal damage mechanism of different rocks and its effect on the rock performance, this study reviews a large number of test results of rock specimens experiencing heating and cooling treatment in the laboratory. Firstly, the variations of macroscopic behaviors, including physical parameters, mechanical parameters, thermal conductivity and permeability, are examined. The variations of mechanical parameters with thermal treatment variables (i.e. temperature or the number of thermal cycles) are divided into four types. Secondly, several measuring methods for microstructure, such as polarizing microscopy, fluorescent method, scanning electron microscopy (SEM), X-ray computerized tomography (CT), acoustic emission (AE) and ultrasonic technique, are introduced. Furthermore, the effect of thermal damage on the mechanical parameters of rocks in response to different thermal treatments, involving temperature magnitude, cooling method and thermal cycle, are discussed. Finally, the limitations and prospects for the research of rock thermal damage are proposed. (c) 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

Maharashtra stands out as a crucial state in India, demonstrating significant progress in infrastructural development and industrialization. Several prominent cities, including Mumbai, Pune, Nagpur, etc., are significantly contributing to the Indian economy. Considering the importance of the state, a deterministic seismic hazard analysis is executed to reduce the damages to critical and important structures and fatalities caused due to earthquakes. Past earthquakes data are collected within and around the state to prepare a homogenised earthquake catalogue. Seven seismic zones are prepared using K- mean cluster analysis. Independent earthquake events i.e., mainshocks are identified using four renowned declustering methods. Additionally, with the help of mainshocks from each zone, the maximum observed earthquake magnitude ( m(max)) and positive correction factor (Delta) are estimated. By superimposing all the m (max) mainshocks (after adding A) onto the fault map, the maximum observed possible earthquake magnitude of all faults (M-max) are assigned to each fault. M-max value is used to estimate surface rupture length (RLD) and consecutively, the maximum magnitude (M-Max) from fault sources are estimated. Three region-specific ground motion prediction equations (GMPEs) are adopted in the logic trees assigning a proper weightage to each GMPE. A seismic hazard contour maps are prepared at bedrock level, C, and D-type soil sites for Maharashtra. In the western part of the study area, the maximum PGA value is found to be 0.58 g, 0.70 g, and 0.33 g at bedrock level, C, and D-type sites, respectively.