Large-scale landslides are widespread and undergo a long-term process of damage accumulation under multi-stage rainfall. Landslides may cause catastrophic damage months or years later, threatening human lives and property. In this study, we focus on the fatigue weakening process of landslides by multi-stage rainfall. We design innovative rainfall-step creep experiments for the shear zone materials of large-scale creep landslides to study the correlation between multi-stage rainfall and landslide deformation. The experimental results show that each rainfall will cause a rapid increase in pore water pressure, which subsequently triggers a short-term acceleration in the deformation of the shear zone material, followed by a transition into a steady-state creep phase. With the increase in rainfall, the number of rainfalls required to trigger failure decreases, the secondary creep time is significantly shortened, and the landslide enters the tertiary creep faster. Under the same rainfall conditions, the lower the stress, the significantly longer the secondary creep time, but the failure occurs earlier, showing a high sensitivity of the shear zone material to rainfall. The rainfall-step creep experiments quantitatively demonstrate the on-site behavior of landslides, showing a cumulative destructive effect of multi-stage rainfall on landslides. Our results exhibit insights for a better understanding of the large-scale landslide from creep to failure.

The seismic noise measurement is widely used to investigate soil slopes due to their sensitivity to changes in material properties and their ability to investigate subsurface features at greater depths, but its application to deep rock landslides remains underexplored. Here, we apply the seismic noise measurement to investigate the geological structure of a deep rock landslide, the Tizicao (TZC) landslide. We deployed 107 single-station seismic noise monitoring sites across the TZC landslide and integrated the data with borehole information and other geophysical techniques, including multichannel analysis of surface waves and electrical resistivity tomography. The inversion process couples multiple methods to develop a three-dimensional geological model of the TZC landslide, which will benefit in estimating the location of the sliding surface. Meanwhile, the landslide volume can be calculated more accurately. Our results demonstrate that seismic noise measurements are an efficient, nondestructive, and rapid technique suitable for characterizing large, deep rock landslides. This approach not only improves our ability to simulate such landslides with greater accuracy but also contributes to providing reliable early warning and landslide management strategies.

Earthquake-triggered (coseismic) landsliding is among the most lethal of disasters, and rapid response is crucial to prevent cascading hazards that further threaten lives and infrastructure. Current prediction approaches are limited by oversimplified physical models, regionally focused databases, and retrospective statistical methods, which impede timely and accurate hazard assessments. To overcome these constraints, we developed the first comprehensive global database of ∼400 000 landslides associated with 38 of the most catastrophic earthquakes over the past 50 years. Leveraging this extensive dataset, we developed advanced deep-learning models that predict the probability of landsliding for any earthquake worldwide with an average spatial accuracy of ∼82% in less than a minute, without relying on prior local knowledge. Our framework enables swift disaster evaluation during the critical early hours following an earthquake while also enhancing pre-event hazard planning. This study offers a scalable and efficient tool to mitigate the catastrophic impacts of earthquake-triggered landslides, representing a transformative advance in global geohazard prediction.

Traditional Newmark models estimate earthquake-induced landslide hazards by calculating permanent displacements exceeding the critical acceleration, which is determined from static factors of safety and hillslope geometries. However, these studies typically predict the potential landslide mass only for the source area, rather than the entire landslide zone, which includes both the source and sliding/depositional areas. In this study, we present a modified Newmark Runout model that incorporates sliding and depositional areas to improve the estimation of landslide chain risks. This model defines the landslide runout as the direction from the source area to the nearest river channel within the same slope unit, simulating natural landslide behavior under gravitational effects, which enables the prediction of the entire landslide zone. We applied the model to a subset of the Minjiang Catchment affected by the 1933 MW 7.3 Diexi Earthquake in China to assess long-term landslide chain risks. The results indicate that the predicted total landslide zone closely matches that of the Xinmo Landslide that occurred on 24 June 2017, despite some uncertainties in the sliding direction caused by the old landslide along the sliding path. Distance-weighted kernel density analysis was used to reduce the prediction uncertainties. The hazard levels of the buildings and roads were determined by the distance to the nearest entire landslide zone, thereby assessing the landslide risk. The landslide dam risks were estimated using the kernel density module for channels blocked by the predicted landslides, modeling intersections of the total landslide zone and the channels. High-risk landslide dam zones spatially correspond to the locations of the knickpoints primarily induced by landslide dams, validating the model’s accuracy. These analyses demonstrate the effectiveness of the presented model for Newmark-based landslide risk estimations, with implications for geohazard chain risk assessments, risk mitigation, and land use planning and management.

Determining the shear‐velocity dependence of dry granular friction can provide insight into the controlling variables in a dry granular friction law. Some laboratories believe that the quality of this study is at the forefront of the discipline for the following reasons. Results suggest that granular friction is greatly affected by shear‐velocity (v), but shear experiments over the large range of naturally occurring shear‐velocities are lacking. Herein we examined the shear velocity dependence of dry friction for three granular materials, quartz sand, glass beads and fluorspar, across nine orders of magnitude of shear velocity (10−8–2 m/s). Within this range, granular friction exhibited four regimes, following a broad approximate “m” shape including two velocity‐strengthening and two velocity‐weakening regimes. We discuss the possible physical mechanisms of each regime. This shear velocity dependence appeared to be universal for all particle types, shapes, sizes, and for all normal stresses over the tested range. We also found that ultra‐high frequency vibration as grain surfaces were scoured by micro‐chips were formed by spalling at high shear velocities, creating ∼20 μm diameter impact pits on particle surfaces. This study provides laboratory laws of a friction‐velocity (μ‐v) model for granular materials.

The 2008 Wenchuan Ms8.0 earthquake triggered a catastrophic landslide, i.e., the Daguangbao (DGB) landslide (1.2 x 10(9) m(3)). Its shear failure occurred within a deep-seated (average depth of 400 m) saturated carbonate bedding fault in the Paleozoic Formation. The frequent seismic events in the tectonic belt make the landslide initiation mechanism more complex. Shake table tests were conducted on the DGB landslide to understand the coupling effect of multiple earthquakes, geology and hydrology. The results showed that the multiple earthquakes weakened the friction coefficient as the Boltzmann function on the sliding surface of the landslide. The friction law of the basal surface related to seismic energy was established and incorporated into the Newmark analysis. And the seismic energy consumed in the steep scarp surface release of landslide during an earthquake is also considered. It found that the traditional Newmark model overestimates the time for earthquake-induced landslides due to ignoring the steep scarp surface release stage. It proposed that evaluating pre-earthquake induced slope damage, and critical seismic energy for triggering co-seismic landslides are important for predicting post-seismic landslides.

Abstract Understanding the motion of particles in very dense granular flows is crucial for comprehending the dynamics of many geological phenomena, and advancing our knowledge of granular material physics. We conduct transparent ring shear experiments to directly observe the granular motion under relatively high‐pressure conditions, and find that the granular velocity non‐linearly decays, forming an approximately 7‐particle‐diameter‐thick localized shear band. A fitting curve underlying non‐local physics can be used to well predict velocity profile geometries that are almost independent of normal stress and shear velocity. Moreover, experimental results show monotonically decreasing granular kinetic temperature, which may be caused by energy dissipation due to more inelastic contacts under high confining pressures. The variation of granular temperature will significantly influence the local yield stress and rheological properties, which may lead to inhomogeneous fluidity of the material and thus to shear localization in very dense granular flows.

In the early hours of June 24, 2017, a major landslide event occurred in Xinmo Village, Sichuan Province, China. The landslide instantly devastated the whole village. Ten people died and 73 were missing in this major landslide event. The study area has suffered from several strong earthquakes in the past 100 y. Present studies have reported that the cumulative damage effect of the Xinmo landslide induced by earthquake is obvious. In this study, we conducted a shaking table test based on the detailed geological survey, historical seismic data, satellite optical image, unmanned aerial vehicle photography. The test result presents the characteristics of multistage seismic damage and progressive deformation process of the Xinmo landslide model, and shows that the historical earthquakes have caused serious damage to the interior of rock mass in the source area. The test also shows that the cumulative damage of the model increases with an increase in duration of earthquake loading. When the excitation intensity increases to a certain value, the damage accumulation velocity of the model suddenly increases. It reveals that frequent historical earthquake loads can be regarded as a main reason for the damage and deterioration of landslide rock mass. Damage accumulation and superposition occur in the slope. Under a long-term gravity, deformation of the slope gradually increases until catastrophic failure is triggered. The progressive deformation process of slope is summarized. Firstly, under strong earthquakes loading, a tensile fracture surface forms at the rear edge of the wavy deformation high and steep bedding slope. It reaches a certain critical depth and expands along the interlayer structural plane. Meantime, damaged fissures perpendicular to the structural plane also appear in the steep-gentle turning area of the slope. Secondly, under a coupling action of seismic loading and gravity, the interlaminar tensile crack surface at the rear edge of the slope extends to depth continuously. Meanwhile, rock fracture occurs in the steep-gentle turning area. The “two-way damage propagation” mode of the inter-layer tensile crack surface occurs until the sliding surface is connected. However, due to the “locking section” effect of rock mass at the slope foot, it can still maintain a short-term stability. Thirdly, under the influences of the heavy rainfall before a landslide and the long-term gravity of the upper sliding mass, rock mass in the steep section at the slope foot breaks outward. Finally, a catastrophic landslide occurs.

Earthquake-triggered landslides are widely recognized. Despite extensive research on the seismic responses of landslides triggered by single earthquakes, there is a lack of understanding of the seismic responses of landslides due to earthquake sequences and multiple earthquakes, and the mechanisms of dynamic weakening under multiple earthquakes still lack support from experimental results. To explore their seismic response characteristics and triggering mechanism, a series of multi-period vibrations ring shear tests and dynamic triaxial-bender tests were conducted with glass spheres. The experimental results show that the co-vibration slip occurred during the vibration process, and as the vibration periods increased, the sample gradually slipped after vibration, eventually leading to accelerated instability. The sample exhibited a transition from a solid-semi-solid state to a liquid state due to the increase in vibration periods. Further results show that the shear modulus progressively weakened with successive vibration periods. The weakening of the shear strength of the sample caused by multi-periods vibration was affected by the amplitude, the vibration time, and the interval time between two periods of vibration. Our study provided insights into how multiple earthquakes of seismic sequence and seismically active area trigger landslides. Plain Language Summary Earthquake-triggered landslides are affected by seismic sequences and multiple earthquakes in the geological history, but how multiple earthquakes trigger landslides is still unclear. In view of the dynamic response characteristics and triggering mechanism of landslides triggered by multi-stage earthquakes, we carried out dynamic ring shear experiments and dynamic triaxial-bender experiments. The experimental results show that with an increase in the number of vibration period, the sample initially experienced no deformation after vibration, followed by decelerated deformation, and finally underwent accelerated unstable deformation, showing a phase transition process from solid-semi solid to liquid. The experimental results further indicate that this was because the shear modulus of the sample decreased with the increase of the vibration period. Our results revealed how multiple earthquakes and seismic sequences trigger landslides.

Understanding particle fragmentation and its resulting particle-size distribution is essential for comprehending shear zone formation, structure, and frictional behavior in faults and landslides, particularly at high normal stresses. 3-D fractal dimension (D3) is used as a measure of particle-size distribution, and for the potential self-similarity physics. Previous research suggests D3 - 2.58 based on the "constrained comminution" model, or D3 = 3.00 considering large shear displacement. However, field data from rock avalanches reveal scattered D3 that deviate from these predictions, possibly due to the neglection of the underlying fragmented physics, such as the particle-size-dependent fragmentation probability. Herein, we conducted rotary shear experiments to investigate the evolution of D3 under varying normal stresses, velocities, and mineral compositions. Experimental results demonstrate that D3 monotonically increases with shear displacement and converges to an ultimate value, significantly influenced by mineral composition but less affected by shear velocity and confining stress within the experimental conditions. A modified large-strain model that considered size-dependent grain-breakage probability was proposed, which may explain the observed divergence of D3 from previous predictions. This model highlights the complex mechanisms involved in particle breakage within dense grain-flows, resulting in the high but scattered D3 observed in natural shear zones. Furthermore, we recognize that additional mechanisms, such as abrasion and grinding, can contribute to the particle size reduction and influence the ultimate fractal dimension. This study provides valuable insights into the dynamics of particle fragmentation in shear zones and has implications for understanding various geological processes. The fragmentation of coarse particles is a common process in geological processes such as earthquakes and landslides. Understanding how these particles break down and the resulting range of particle sizes is crucial because it directly influences the mechanical behavior of fault zones and landslide shear zones. To characterize the distribution of particle sizes, scientists often use a parameter called "fractal dimension." This value not only describes the proportions of different-sized particles but also reveals whether the patterns of particle breakage exhibit self-similarity across different scales. We conducted laboratory experiments using a ring shear apparatus, a device that simulates the shearing through rotation. Our results demonstrate that when particles undergo long-distance shearing, they generate a significantly larger proportion of fine particles compared to common fragmentation processes, leading to a higher fractal dimension. Furthermore, we discovered that the mineral composition of the particles plays a significant role in influencing the ultimate fractal dimension. This is likely because particles of different sizes and compositions have varying probability of being crushed during the shearing process. These findings provide a deeper understanding of earthquake and landslide dynamics and may offer evidence for inferring past dynamic processes based on the observed particle size distribution. The fractal dimension of particle size distribution increases with shear strain and tends to an ultimate value The ultimate fractal dimension is less affected by shear strain rate and confining stress, yet it is notably influenced by the lithology Complex fragmentation dynamics can explain scattered fractal dimensions with a value of similar to 3.00 in many natural shear zones

Shear zone is widely observed in natural faults and landslides as well as laboratory experiments on granular material. Understanding the shear-zone evolution process in granular materials is crucial in studying the dynamics of the landslides and faults. However, it is still not well understood. To this end, we conducted a series of ring-shear experiments to investigate the evolution of strain localization and shear-zone internal structure in cohesive and non-cohesive granular materials. The quantitative evaluation was conducted by using high-solution X-ray computed tomography (CT). The analyses included visualization of shear-zone internal structure and quantification of particle shapes, orientations, and grain-size distributions at different shear strain levels. We found that with the increase of shear displacement, the large particles inside the shear zone became more and more rounded, but without an orientation, wear and attrition resulted in an abundance of nanoparticles within the shear zones. We also found fine-particle layers (nanoparticle layers) formed on either side of shear zones during shear localization, implying that shear development progressed from a shear zone to an interface. These findings offer some new understanding of the evolution of shear zones in granular materials.

Fast and slow earthquakes are two modes of energy release by the slip in tectonic fault rupture. Although fast and slow slips were observed in the laboratory stick-slip experiments, due to the sampling rate limitation, the details of the fault thickness variation were poorly understood. Especially, why a single fault would show different modes of slip remains elusive. Herein, we report on ring shear experiments with an ultrahigh sampling rate (10 MHz) that illuminate the different physical processes between fast and slow slip events. We show that the duration of slips ranged from dozens to hundreds of milliseconds. Fast slip events are characterized by continuous large-amplitude AE (acoustic emission) and somewhat intricate variation of the sample thickness: A short compaction pulse during the rapid release of stress is followed by dilation and vibrations of the sample thickness. As the slip ends, the thickness of the sample first recovers by slow compaction and then dilates again before nucleation of the following slip event. In contrast, during slow slip events, the shear stress reduction is accompanied by intermittent bursts of low-amplitude AE and sample dilation. We observed the detailed thickness variation during slips and found that dilation occurs during both fast and slow slips, which is consistent with natural observations of coseismic dilatation. This study may be used to reveal the mechanism of fault slips during fast and slow earthquakes, which explain the potential effect of fast and slow slips on stress redistribution and structural rearrangement in faults.

In recent years, landslides induced by underground mining have attracted much attention as they cause great harm and early warning signals are difficult to detect. The key work of the early warning of a mining landslide is to clarify its initiation mechanism and evolution process. Due to the complexity of the deformation and failure of the goaf overburden and the lack of monitoring of the slope evolution process, the deformation and failure law and evolution characteristics of mining landslides have always been difficult to analyze. In this paper, a typical mining landslide, the Madaling landslide, was selected as the study object. The soft-hard interlayer structure of the slope was generalized and explored by centrifuge model tests and a 3D discrete element model. The results showed that the evolution of the Madaling landslide are divided into four stages: (I) the bending and collapse of the goaf overburden, the slope settlement and the formation of tensile cracks at the trailing edge; (II) the upwards extension of the subsidence cracks of the rock mass; (III) the occurrence of shear cracks in the rock mass, with gradual slope deformation as a whole; and (IV) the connection of shear cracks, with the initiation of landslides. The long-term gravity creep of soft rock and the extension of trailing edge tensile cracks cause the internal rock mass of the slope to become the key block controlling slope stability. The slope surface displacement ( S )-time ( t ) curve of mining landslides is divided into the settlement stage, rock mass crack development stage and landslide evolution stage. The formation time of shear cracks in the rock mass crack development stage is a sign of the transformation of subsidence into a landslide. The relationship between the horizontal displacement and the depth of the rock mass effectively reflects the development stage of shear cracks. The horizontal and vertical displacement of the deep rock mass can serve as the early warning criterion for mining landslides.

Stress accumulation and release reflected by acoustic emissions (AEs) during shearing of granular materials provide important information on failure mechanisms in seismic faults and landslides controlled by stick‐slip. Among many characteristics (amplitude, energy, counts, and frequency) of AE signals generated by stick‐slip, stress changes corresponding to various frequency AEs in different stages of the stick‐slip process are not clear, which limits our knowledge of the characteristics of precursory signals before stick‐slip failure. To better understand the physical mechanisms of granular stick‐slip, we monitored the mechanical and AE signals using high‐frequency (2 MHz) synchronous acquisition during constant‐speed shear of packs of uniform glass beads with different sizes at different normal stresses. The release rate of AE energy was found to accelerate with the dilatation of the sample volume, and the stress drop of stick‐slip was augmented with the increase of normal stress and particle size. Three characteristic events of single cycle stick‐slip were observed in this study: main slip, minor slip, and microslip. We analyzed the AE frequency spectra of these three event types. Both main slip and minor slip corresponded to stress drop and generated high‐frequency AEs (about several hundred kHz), while the AE frequencies generated by microslip were lower (about tens of kHz) and exhibited stress strengthening, which were not apparent in previous studies due to the low frequency of acquisition. We propose that the microslip is mainly due to sliding on grain contacts, while the main slip and minor slip resulted from breakage and reforming of force chains. Low‐frequency AEs from microslip may suggest a crucial precursor of seismic faults and landslides.

全国人民代表大会常务委员会: 按照环境保护法规定和全国人大常委会安排,受国务院委托,就 2022 年度环境状况和环境保护目标完成情况报告如下,请审议. 2022 年是党和国家历史上极为重要的一年.党的二十大描绘了全面建设社会主义现代化国家的宏伟蓝图,就推动绿色发展、促进人与自然和谐共生作出重大战略部署.

The M s 8.0 Wenchuan earthquake of 2008 dramatically changed the terrain surface and caused long-term increases in the scale and frequency of landslides and debris flows. The changing trend of landslides in the earthquake-affected area over the decade since the earthquake remains largely unknown. In this study, we were able to address this issue using supervised classification methods and multitemporal remote sensing images to study landslide evolution in the worst-affected area (Mianyuan River Basin) over a period of ten years. Satellite images were processed using the maximum likelihood method and random forest algorithm to automatically map landslide occurrence from 2007 to 2018. The principal findings are as follows: (1) when compared with visual image analysis, the random forest algorithm had a good average accuracy rate of 87% for landslide identification; (2) postevent landslide occurrence has generally decreased with time, but heavy monsoonal seasons have caused temporary spikes in activity; and (3) the postearthquake landslide activity in the Mianyuan River Basin can be divided into a strong activity period (2008 to 2011), medium activity period (2012 to 2016), and weak activity period (post 2017). Landslide activity remains above the prequake level, with damaging events being rare but continuing to occur. Long-term remote sensing and on-site monitoring are required to understand the evolution of landslide activity after strong earthquakes.

Complex geological problems caused by natural environment have emerged constantly, causing serious damage to the land use and groundwater ecological environment in the western region. How to deal with the relationship between the above factors and ecological environment protection is a new research topic at present. Broken rock mass, cracks and water inrush during construction can be blocked and reinforced by grouting to achieve environmental protection. Therefore, to develop accurate quantitative models for the hydration of cement and predict the properties of grouting materials plays a crucial role during the protection process. In this study, the hydration product Ca(OH)2 is taken as an example, and the adsorption processes of different functional groups on the surface of Ca(OH)2 were investigated using DFT. The adsorption energy of the (101) surface was −0.38 Ha in sulfonic group, the lowest on different crystal planes of Ca(OH)2, while the adsorption energy of different functional groups is sulfonic group > carboxyl group > amide group > benzene ring. The adsorption energy was the lowest when the hydroxyl and carboxyl ratio was 1:1, suggesting that the adsorption energy and hydration performance in different ratios of hydroxyl and carboxyl groups will also be discrepant. After the adsorption of functional groups with Ca(OH)2, the electron clouds and orbitals rearranged, new characteristic peaks of the s orbital were present in the vicinity of −15 eV, −13 eV, and −10 eV, respectively. Since the relationship between functional groups and cement hydration process of chemical admixtures was explored, the mechanism of the cement hydration reaction and the influence of cement-based admixtures was revealed from an electronic view, also to extract the key influencing factors for the grouting and develop accurate quantitative models to predict and tackle various geo-environmental hazards.

The 2017 catastrophic Xinmocun landslide was triggered on a bedding slope in the Songpinggou Gully, Maoxian County, China. Previous research primarily focused on the dynamic slope response and deformation characteristics of a single earthquake, and focus on the effect of damage accumulation on slope stability is lacking. The shaking table tests were conducted in this study to understand historical earthquake-induced damage accumulation in bedding slopes. The acceleration amplification coefficient (BPGA) and plastic effect coefficient (PEC) were used to reflect the damage accumulation of bedding slope under the influence of multiple earthquakes. The results revealed that the bedding surface-induced seismic motion amplification contributes to damage constrained on the slope sliding surface. The damage accumulation during multiple earthquakes contributed to slope peak ground acceleration (PGA) amplification increasing and model's natural frequency decreasing in non-linearly form. The shortening of the gap between the driving force frequency and the model's natural frequency had a great impact on the slope damage accumulation. These findings suggest that the accumulation of damage caused by historical earthquake amplification contributes significantly to post-earthquake instability. Future evaluations of slope stability should consider the accumulation and reduced frequency of slope deformation associated with multiple earthquakes.