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Process-based rockfall simulation models attempt to better emulate rockfall dynamics to different degrees. As no model is perfect, their development is often accompanied and validated by the valuable collection of rockfall databases covering a range of site geometries, rock masses, velocities, and related energies that the models are designed for. Additionally, such rockfall data can serve as a base for assessing the model’s sensitivity to different parameters, evaluating their predictability and helping calibrate the model’s parameters from back calculation and analyses. As the involved rock volumes/masses increase, the complexity of conducting field-test experiments to build up rockfall databases increases to a point where such experiments become impracticable. To the author’s knowledge, none have reconstructed rockfall data in 3D from real events involving block fragments of approximately 500 metric tons. A back analysis of the 2015 Mel de la Niva rockfall event is performed in this paper, contributing to a novel documentation in terms of kinetic energy values, bounce heights, velocities, and 3D lateral deviations of these rare events involving block fragments of approximately 200 m3. Rockfall simulations are then performed on a “per-impact” basis to illustrate how the reconstructed data from the site can be used to validate results from simulation models.

In this paper, a geological–geotechnical rock slope classification system is presented, providing a central instrument of the safety strategy of the Austrian Federal Railways (OBB) Infrastruktur AG in rockfall protection. The classification, which is based on an evaluation matrix, enables the rock slope maintenance or inspection interval to be adapted to the geological and geomorphological characteristics of the respective rock slope. The aim is to achieve a reduction of the scope of work by adapting the inspection intervals to the expected rockfall activity. This prioritisation can be used to determine the annual cost-intensive rock scaling to be carried out on a 1- to 3-year interval. Although this semiquantitative method was especially developed for assessing rockfall hazards on rock slopes above rail lines, it could also be applied to other transport infrastructures.

Jointed network simulations tend to be more random in nature due to the uncertainty of rock mass structures. In this paper, a series of jointed network models can be established in batches using Monte Carlo simulation (MSC) and loop iteration. Taking the joints, tunnel profile and their intersections as the edges E and vertices V of graph G, the jointed network model can serve as an unweighted undigraph. Then, the breadth-first search is introduced to search the closed paths around the tunnel profile, such as the potential key blocks. With batch simulation of network models, the spatial distribution characteristics and probability distribution rules of blocks can be automatically analysed during the search process. For comparison, the Laohushan tunnel of the Jinan Belt Expressway in China has been analysed using the breadth-first search, discontinuous deformation analysis method and procedure of “Finding the Key Blocks-Unrolled Tunnel Joint Trace Maps”. Each simulation starts from the same probabilistic model of geometrical parameters of joints but develops differently with different outcomes. The spatial distribution rule of potential key blocks simulated by the aforementioned batch jointed network models is essentially identical to the actual rockfall during tunnel excavation.

The quantitative study of earthquake-triggered rockfall debris along seismogenic fault zones has proven to be a valid approach for use in identifying paleo-earthquakes and faulting activities. After the 2010 Yushu earthquake, paleo-rockfall research employed U-series dating of calcareous coats on the rockfall surface, and the results provided chronological evidence of multi-period features relating to earthquake-triggered rockfalls that have occurred along the Yushu fault. In this study, the mechanism involved in forming the calcareous coat on seismic rockfall surfaces was analyzed to further explain the significance of conducting associated U–Th aging analyses. For earthquake-triggered rockfall regions, the U–Th age of the calcareous coat can be used as a proxy age of the rockfall formation, and the timing of the related paleo-earthquake event can be constrained. Based on all current existing age data, an in-depth comparison was made between the U–Th ages of calcareous coats obtained from five seismic rockfall sites and other 14C dating results obtained from trenches and paleo-seismic landslides relating to paleo-earthquakes. Combined with the results of field investigations, four individual paleo-earthquakes that triggered rockfalls of different scales in historical time were identified. These results imply that multi-period earthquake-triggered rockfalls along the Yushu fault may be valid time indicators of seismic events and reflect the intensity and meizoseismal scale of relevant paleo-earthquake events. This exploratory research on the U-series dating of calcareous coats from earthquake-triggered rockfalls in Yushu can be used as a valuable reference for paleo-earthquake studies in other tectonically active regions.

The performance of a structurally dissipating rock-shed (SDR) depends largely on the capacity of its energy dissipators. At present, most energy dissipators are made of metals, which dissipate energy by unrecoverable plastic deformation. Therefore, they are not able to recover their energy-dissipation capacity after deformation under rockfall impact. However, a rockfall usually disintegrates into pieces when it rolls down from a higher position and results in multiple rockfall impacts. An energy dissipator with self-recovery capability is therefore more suitable for ensuring the safety of SDRs. Replacing metal with polyurethane (a hyperelastic material with remarkable self-recovery capability) can provide self-recovery capability for energy dissipators, making them more suitable for resisting multiple rockfall impacts. In this work, polyurethane was manufactured into two types of energy dissipators: cylindrical and cubical. Full-scale falling rock impact tests and dynamic numerical simulations were conducted to study the mechanical response of the energy dissipators. In addition, in order to ensure the accuracy of the simulation, the dynamic mechanical properties of the polyurethane were tested and its dynamic constitutive model was established. The experimental and simulation tests have clarified the advantages of the polyurethane energy dissipator. We also summarized the practical considerations in the design of energy dissipators.

The spatial and temporal quantification of rockfall frequency remains a major challenge in mountain environments, especially also in terms of rockfall management. Approaches that have been used traditionally to quantify rockfall frequency include historical records, remote sensing, or in situ monitoring, but have been shown repeatedly to suffer from a lack of completeness or to rely on rather short time series (of a few years) that are, in addition, limited to small areas. As such, they normally cannot meet the stringent requirements of hazard and risk analyses. Here, we propose a new procedure coupling field analysis of rockfall deposits in mitigation structures and growth disturbances in tree-ring series with three-dimensional (3D), process-based rockfall modeling to estimate rockfall frequencies for individual cliff compartments. This procedure has been tested on a slope in the Swiss Alps (La Fory, Sembrancher VS), where rockfall triggered from a 38 hm $$^{2}$$ cliff to threaten a 1-km-long section of the road to the Grand St. Bernard tunnel and the local railway line. Based on 84 rockfall deposits retrieved from 420-m-long protection barrier and growth disturbances in trees over the 1994–2017 period, we estimate rockfall hazard to between 0.043 and 0.348 events yr $$^{-1}$$ at various locations on the slope. In total, we used 68,680,000 rockfall simulations to translate hazard values into rockfall frequencies at the cliff level. Converging release frequencies between tree-ring analyses (0.99–1.35 events yr $$^{-1}$$ hm $$^{-2}$$ ) and values obtained from deposits in the protection barrier (0.82 events yr $$^{-1}$$ hm $$^{-2}$$ ) confirm the reliability of our procedure. Despite remaining limitations, our approach enables precise quantification of rockfall release frequency in a holistic and reproducible manner both in space (a few hm $$^{2}$$ ) and time (several decades), and thus yields the data needed for hazard and risk mapping. We therefore recommend, where applicable, to include this procedure in future rockfall management strategies.

At 6pm on July 19, 2019, the Yahuokou earthflow (Zhouqu County, Gansu Province, China) was reactivated following a period of intense rainfall. A volume of approximately 3.9 × 106 m3 travelled approximately 1100 m in 27 days, blocking part of the Min River. Multi-temporal InSAR monitoring and interpretation of high-resolution optical images were used to map different phase of mass movements (including rock fall, topple, slide, and flowslide) to characterize the pre-failure deformation of the earthflow. Analysis of displacement patterns indicates that initiation of the earthflow is closely correlated with road construction, intense and long-lasting rainfall (443 mm from April 1, to July 19, 2019), and seismic activity. The potential to forecast the time of failure based on pre-failure deformation patterns observed by InSAR monitoring is demonstrated. Three types of pre-failure deformation are distinguished: steady creep, fluctuating creep, and accelerating creep. The monitoring process enabled identification and characterization of three key stages of the earthflow (initiation, transportation, and accumulation/deposition) providing important lessons learned for improvement of landslide early warning and hazard assessment in similar geological and geomorphological settings.

Geohazard recognition and inventory mapping are absolutely the keys to the establishment of reliable susceptibility and hazard maps. However, it has been challenging to implement geohazards recognition and inventory mapping in mountainous areas with complex topography and vegetation cover. Progress in the light detection and ranging (LiDAR) technology provides a new possibility for geohazard recognition in such areas. Specifically, this study aims to evaluate the performances of the LiDAR technology in recognizing geohazard in the mountainous areas of Southwest China through visually analyzing airborne LiDAR DEM derivatives. Quasi-3D relief image maps are generated based on the sky-view factor (SVF), which makes it feasible to interpret precisely the features of geohazard. A total of 146 geohazards are remotely mapped in the entire 135 km2 study area in Danba County, Southwest China, and classified as landslide, rock fall, debris flow based on morphologic characteristics interpreted from SVF visualization maps. Field validation indicate the success rate of LiDAR-derived DEM in recognition and mapping geohazard with higher precision and accuracy. These mapped geohazards lie along both sides of the river, and their spatial distributions are related highly to human engineering activities, such as road excavation and slope cutting. The minimum geohazard that can be recognized in the 0.5 m resolution DEM is about 900 m2. Meanwhile, the SVF visualization method is demonstrated to be a great alternative to the classical hillshaded DEM method when it comes to the determination of geomorphological properties of geohazard. Results of this study highlight the importance of LiDAR data for creating complete and accurate geohazard inventories, which can then be used for the production of reliable susceptibility and hazard maps and thus contribute to a better understanding of the movement processes and reducing related losses.

A rockfall is a typical dynamic problem of a discontinuous block system originating from a dangerous rock mass and always presents serious geo-hazards along highway slopes in mountainous areas. This study aims to investigate the failure mechanisms and movement characteristics of rockfalls through a three-dimensional discontinuous deformation analysis (3D DDA) method and attempts to comprehensively examine the complicated kinematic process of rockfall disasters. In terms of the initial failure and post-movement characteristics (i.e., motion trajectory and kinetic energy) of a rockfall, the effectiveness of 3D DDA is verified by comparing its results with those of laboratory experiments. Taking the K4580 typical high-steep slope undergoing rockfalls along the G318 national highway in Tibet as an example, the initiation and failure of a single boulder and a large-scale rock mass at the source area were simulated by 3D DDA. Then, the movement characteristics of the boulder and massive collapsing rocks along the slopes of different geometrical characteristics, i.e., the slopes before the landslide and after the shallow and deep landslides, were studied. The results show that the 3D DDA has significant advantages in analysing the failure mechanisms of slope rockfalls and can satisfactorily simulate the spatial movement (e.g., lateral deviation and deflection) of blocks by considering the 3D geometry of the slopes and blocks. The 3D DDA numerical simulation can predict the movement range, deposition position, and affected area of rockfall disasters, which can provide a basis for formulating disaster prevention countermeasures in actual projects.

The current research on the deformation of buried pipeline under rockfall impact load is generally based on the analysis of the pipeline cross-sectional deformation, and the deformation caused by lateral deflection of pipeline is less considered. The two-stage method is introduced to analyze the deformation of the adjacent buried pipeline by rockfall impact. The first stage solves for the additional stress caused by rockfall impact in the pipeline, and the second stage solves for the pipeline deformation caused by the additional stress. The validity and accuracy of the method in this paper are verified by comparing with the solutions in the existing literature. In addition, the influence law of pipe diameter, wall thickness, burial depth, rockfall action position and rockfall impact velocity on the deformation of buried pipes is analyzed. The research results show that for certain working conditions and soil parameters, there will be an optimal pipeline diameter D, which minimizes the deformation of the buried pipeline under the rockfall impact; based on Pasternak foundation model and Winker foundation model to calculate the rockfall impact load on buried pipe deformation respectively, it is found that the difference between these two foundation models on pipe deformation is small.

Seismic and acoustic signals induced by rock falls and rock avalanches always contain abundant information about movement processes. By simultaneously monitoring and analyzing the characteristics of the two physical signals, there is a better opportunity to closely interpret the behaviors of the processes closely. This study conducted small-scale rock fall field tests on a creek bank. Three types of field tests including single large rock fall, single small rock fall, and rock-mixture fall tests were carried out. Low cost and easy-to-install accelerometers and microphones were used to record both seismic and acoustic signals, respectively. The results affirm that the characteristics of the seismic and acoustic signals are generally similar and correlated due to the signals being caused by the same event energy sources. The attenuation of acoustic signals was less than that of seismic signals and high-frequency portion of the seismic signals attenuates quickly in stratum. It was also shown how the surface wave velocity of the stratum of the test site was estimated. In addition, the larger the rock mass, the lower the seismic frequency was found to be. The possible practical significance of this study is provided, and the simultaneous use of acoustic and seismic signal monitoring to rock falls/landslides is promoted.

The Samos Island (Aegean Sea) Earthquake occurred on 30 October 2020. It produced a tsunami that impacted coastal communities, ground shaking that was locally amplified in some areas and that led to collapse of structures with 118 fatalities in both Greece and Turkey, and wide-ranging geotechnical effects including rockfalls, landsliding, and liquefaction. As a result of the global COVID-19 pandemic, the reconnaissance of this event did not involve the deployment of international teams, as would be typical for an event of this size. Instead, following initial deployments of separate Greek and Turkish teams, the reconnaissance and documentation efforts were managed in a coordinated manner with the assistance of international partners. This coordination ultimately produced a multi-agency joint report published on the 2-month anniversary of the earthquake, and this special issue. This paper provides an overview of the reconnaissance activities undertaken to document the effects of this important event and summarizes key lessons spanning topic areas from seismology to emergency response.

Post-landslide high slopes have always been at increased risk for rockfall disasters, posing a considerable threat to the slope toe area and making it very difficult to manage. In this paper, a comprehensive rockfall hazard assessment strategy based on high-resolution terrestrial laser scanning is proposed. A high-resolution digital terrain model was obtained based on terrestrial laser scanning (TLS) and data processing. Combined with a three-dimensional (3D) probabilistic model, the movement of rock blocks is simulated, and the mechanical parameters for simulation are corrected by 3D back analysis. Finally, based on hierarchical analysis process (AHP) and raster calculation, a rockfall hazard map can be obtained. The method was applied to analyze rockfall hazards on the post-landslide rock slope in Ganluo County. It was found that the rockfall hazard of the post-landslide slope is a great threat to the personnel and equipment of the emergency rescue at the site, and its long-term rockfall risk is also a big hidden danger to the railway at the foot of the slope. The planned 3 m high and 1500 kJ energy capacity protection net has 87.22% interception efficiency, but it is difficult to stop the falling rocks with high speed or high bouncing height. According to the characteristics of rockfall hazards, recommendations for rockfall hazard mitigation measures are proposed, including two aspects of rockfall source area remediation and rockfall transport path blocking. The case of rockfall hazard assessment in Ganluo County provides new methods and ideas for the management of rockfall hazard on post-landslide rock slopes.

To evaluate the ultimate capacity of the ground reinforced embankments, most of the research have been focused on high levels of impact energy. However, many existing embankments have been impacted by several blocks without collapsing. The residual characteristics and efficiency of post-impact embankments under low-energy impact are researched in this paper. Model tests of two types of embankments are compared to investigate the deformation performance and damage evolution of embankments. A simplified analytical approach, based on the test results and the energy method, is proposed to assess the residual efficiency of the post-impact embankments. Furthermore, the adverse impact conditions are analyzed by numerical simulation. The results show that the damage evolution of the embankments goes through three phases, uphill face compression, downhill face displacement, and collapse. Compared with experimental data, the stability calculation method is proved to be feasible. It is also found that the impact location and inclination of the blocks affect the deformation and stability of the embankments significantly. These points should be beneficial to the design of ground reinforced embankments.

This study exploited the historical rockfall inventory and the meteorological stations database of Mont Cervin and Mont Emilius Mountain Communities (Aosta Valley, northern Italy) to decipher relationships between climate processes, typical of mountain environments and rockfall phenomena. The period from 1990 to 2018 was selected as reference to perform the analysis. Climate processes were translated into four climate indices, namely short-term rainfall (STR), effective water inputs (EWI, including both rainfall and snow melting), wet and dry episodes (WD) and freeze-thaw cycles (FT). The comparison between climate indices values at each rockfall occurrence and the statistical distributions describing the whole indices dataset allowed to define not ordinary climatic conditions for each index and their influence on rockfall occurrence. Most of the events analysed (>95% out of 136) occurred in correspondence of the defined not ordinary climatic conditions for one or for a combination of the indices. The relationships between rockfalls and climate showed a seasonality. In spring, most of the events resulted to be connected to FT (70%) while in autumn to EWI (49%). The relative seasonal importance of WD reached its maximum in summer with 23% of the events related to this index alone. Based on these results, different strategies to define empirical critical thresholds for each climate index were explored, in order to make them valid for the whole study area. A preliminary exploratory analysis of the influence of high temperatures and temperature gradients was carried out for some summertime rockfalls, not correlated to the other investigated indices. The presented approach is exportable in neighbouring regions, given the availability of a dated rockfall dataset, and could be adapted to include different processes.

Remote sensing was used to visualize the West region with the purpose of investigating recent natural hazards observed in this area. Various approaches used based on multi-spectral information such as PCA, band compositions, NDVI, and texture analysis are used to investigate landslide and new faults in the region of West Cameroon. The combination of remote sensing techniques with fieldwork and photogrammetry has been probed again and helped to detect three (03) new faults and to characterise the recently assumed landslide as a rock fall characterised by an accumulation of fresh rock deposits downwards, from the edge to the valley. In this study, we extracted in this region all linear and curvilinear edges resulted from geomorphological features, geological structures, rock composition, vegetal tonal contrasts, soil moisture, and human activities. These features are terraces, linear valleys and cliffs, faults, joints, and other line weaknesses, tracks, buildings, roads and rivers. They are overlain on rivers, highways and digital elevation model maps for preliminary validation. Then, a post-processing fieldwork has been conducted to avoid any confusion with faults. The digital elevation model and the derived slope maps enabled fracturing to be discerned. Existing known faults have also been identified in this study.

Albania is located in the Alpine fold belt extending to the central part of the Dinarides–Hellenides arc in a zone characterized by intense tectonic-seismic activity that has a considerable influence in shaping the geo-environment of the area. Historically, strong earthquakes occurred in this region and triggered lots of mass movements causing considerable damages such as life loss, destruction of properties and disruption of the geo-environment. This paper introduces several earthquake-triggered mass movement events in Albania that occurred during 1850–2019. It was achieved through collection and analysis of data from historical studies and authors’ field investigations. The results show that soil type, slope inclination and seismic activity have a direct influence in the occurrence of these movements consistent with similar parameters occurred worldwide. Earthquake’s magnitude and degree of mass movement is well correlated. Mass movements such as lateral earth spread, rock fall, debris slides, sand boils, sand fluidization, cracks and settlement were triggered by earthquakes with a magnitude of 6.0 or higher. On the other hand, lateral rock spread needs a higher seismic magnitude to occur.

The trajectory of a rolling stone begins and is characteristically accompanied by a certain initial rotation. Considering the influence of the initial rotation, the four basic motion forms of a rolling rock movement are analyzed, based on contact mechanics and kinematics principles. The speed calculationF formulas for a rolling rock mass were obtained. Besides, taking the dangerous rock slope of Changheba Hydropower Station in Sichuan Province as an example, the entire moving process of a rolling stone was simulated using “Rocfall software”, and the influence of an initial rotation on total kinetic energy, bounce height, and trajectory of the rolling stone during the movement was analyzed. According to the results, the determination of the most dangerous position during the movement of the rolling stone is not be affected by the initial rotation angular velocity. However, the maximum bounce height of the rolling stone at the most dangerous position increases with the increase of the initial rotation; the initial rotation of a rolling stone affects the longest distance and total horizontal distance. The probability density distribution of total kinetic energy and horizontal distance followed the Gaussian distribution; the influence of initial rotation on the central value can not be ignored. In this case, if the rotation was ignored, the rockfall disaster range would be underestimated, the rate can reach up to 94% when $$\omega =200\hbox {rad/s}$$ . The initial rotation of a rolling stone has a different sensitivity to the slope characteristics. The smooth and hard surface was the most sensitive. The larger the angular velocity, the more sensitive the slope. Therefore, the influence of a rocking stone rotating velocity and slope surface material must be considered in investigating the trajectory of the rockfalls and the provision of protective measures.

Rockfall is a natural hazard that needs to be rigorously managed along all the major road and railways transport networks by identifying the most appropriate mitigation measures. There has been significant progress in rockfall modelling and rockfall protection systems in recent years but there remains one aspect that is not very well understood and quite challenging to account for in the design of rockfall protection structures, namely the fragmentation of falling blocks upon impact. Rocks often break up upon impact, which leads to a change in size, shape and energy of falling blocks, parameters that affect the design of the protective structures. Before being able to incorporate fragmentation into predictive trajectory models, it is required to better understand the fragmentation process and its likely outcome (number, volume of fragments and their trajectories). To that aim, an innovative experimental setup was developed at the University of Newcastle (Australia) to study rock fragmentation upon impact. The setup was designed to perform controlled vertical drop tests and record the following impact parameters: impact force, impulse, impact duration, velocities (of the block before impact and its fragment after impact) and all components of energy, pre and post impact. Six views (four high-speed cameras and two mirrors) are used for an accurate reconstruction of the 3D trajectory of blocks and fragments, in translation and rotation. This paper presents the validation of the setup via two series of drop tests using mortar spheres. Attention was focused on the evaluation of impact force and impulse from load cells placed under the impacted surface, tracking of translational and rotational velocity and the computation of total kinetic energy (before and after impact) and all components of energy dissipation. The results confirm that the experimental setup and the approach developed can be used to obtain impact force, impulse and to compute the energy balance during the impact and fragmentation and conduct advanced fragmentation testing.

The stability properties of a freely rotating rigid body are governed by the intermediate axis theorem, i.e., rotation around the major and minor principal axes is stable whereas rotation around the intermediate axis is unstable. The stability of the principal axes is of importance for the prediction of rockfall. Current numerical schemes for 3D rockfall simulation, however, are not able to correctly represent these stability properties. In this paper an extended intermediate axis theorem is presented, which not only involves the angular momentum equations but also the orientation of the body, and we prove the theorem using Lyapunov’s direct method. Based on the stability proof, we present a novel scheme which respects the stability properties of a freely rotating body and which can be incorporated in numerical schemes for the simulation of rigid bodies with frictional unilateral constraints. In particular, we show how this scheme is incorporated in an existing 3D rockfall simulation code. Simulations results reveal that the stability properties of rotating rocks play an essential role in the run-out length and lateral spreading of rocks., Projekt DEAL

Road Cut Slope Catastrophe (RCSC) is a recent menace threatening vehicular traffic and commuter safety in hilly tracts. Reduction of risk along Road Cut Hill Slope (RCHS) needs to be tackled on priority. National Highway (NH) 60 (formerly NH-50) situated in semi-arid basaltic tract within Chandanapuri Ghat (hill) in Maharashtra is being expanded to enhance economic activity in the allied region. To predict RCSC or landslide activity across the Ghat stretch, eleven (n = 11) road cut slopes were investigated by collecting data regarding (1) slope, (2) RCHS height, (3) distance from road, (4) rock composition, (5) soil structure, and (6) mass movement. Traffic survey was also carried out to understand the vehicular frequency. Survey of India (SOI) 1:50,000 scale toposheet (47/I/3) and LISS-III satellite imagery were used to identify the pre-expansion road situation of the area. Mean rainfall and temperature data were collected from TRMM data, and worldclime grid, respectively, to evaluate climatic nature of the area. Satellite-derived ASTER GDEM data were used to prepare the topographic information. Field investigations, GPS data and traffic survey, space-based remote sensing (RS) satellite-derived data were all integrated in ArcGIS V.9.2 software to produce the composite spatial database of all samples. After that, RCHS site weighting and weighted factor combination (WFC) were carried out to form the Landslide Risk Intensity (LRI), i.e., Low risk (LR), Moderate Risk (MR), High risk (HR), and Very High risk (VHR). Results indicate that out of 11 samples, 2 (P3, P11) are prone to VHR, 3 (P2, P9, P10) prone to HR, 3 (P5, P7, P8) prone to MR, and 3 (P1, P4, P6) prone to RCSC. The results were validated from rock fall activity even though the cut slopes are protected with security net, confirmed by field visit. Thus, investigated RCSC will be useful to evaluate the risk intensity and help evolve suitable remedial measures for RCSC or landslide reduction in the present and other similar areas. It is also recommended to make highway slope maintenance an integral part of highway management.

The Ocona River Valley, in the Arequipa Department in southern Peru, extends over 150 km from the Pacific coast to its headwaters in the Andes Mountains. While traditionally sparsely populated with farmers and crawfish fishermen, the valley has seen a large population growth in the last 20 years as small gold mines have developed. This change poses the opportunity to evaluate three research questions: How do geologic hazards and risks increase from mining activity? How does unplanned urban development affect risks? How do landforms restrict development and thereby increase risks? The combination of climate, topographic, and hydrologic conditions result in widespread hazards from debris flows, collapsible soils, erosion, rockfall, flooding, and liquefaction. We have developed maps of these hazards for three communities where mines have recently developed, Secocha, Alto Molino, and San Juan de Chorunga, and then we conducted a risk analysis for changing conditions, termed “Risk–Risk” analysis. Because of the lack of vegetation on mountain slopes, mining operations typically only affect rockfall hazards, mostly in the immediate vicinity of the mines and in the nearby runout zones. However, increased population and associated settlement infrastructure is constrained by steep slopes and regularly-flooded valleys, so residents live in fan and terrace areas with substantially increased risks from debris flows and collapsible soils and moderately increased risks from flooding and rockfall.

Rock block characteristics are the controlling factors that define the potential rockfall volume, associated hazard and design of preventive practices. The present study defines a methodology to demonstrate the impact of block characteristics on rockfall hazard and its implications on the design of mitigative measures by analysing a recurring rockfall site along a critical highway corridor in NW Himalaya, India. The field data were quantitatively characterised for statistical distributions of size and volume of in situ as well as rockfall blocks. Possible block failures and rockfall initiation zones were predicted using modified kinematic analysis and distinct element method. The size and volume distributions as well as shapes were simulated against these predicted initiation zones to determine the cumulative impact of block characteristics on rockfall hazard by analysing the block kinetics and trajectories. It is found that the block initiation zones majorly govern the relative bounce height, kinetic energy, run-out distance and impact down the slope respective of block sizes and associated mass coupled with slope geometry. However, the effect of block shapes is observed to be minor compared to the blocks greater than a particular size range. Therefore, the design of rockfall protection such as barrier can be more effective when considering the kinetic energies of such block size range assisted by initiation zones. This study proposed that the knowledge of block size frequencies and rockfall initiation zones could provide a rational threshold for which a protection strategy can be designed and optimised to prevent rockfall hazard along the Himalayan highway corridors.

On January 24, 2020, Sivrice–Elazig–Turkey earthquake occurred along the East Anatolian Fault Zone. The moment magnitude of the event was reported as 6.8. This paper documents reconnaissance findings performed immediately after the event. Investigated sites namely, Lake Hazar shores, Karakaya Dam Reservoir–Euphrates River shores, Malatya–Battalgazi district and its villages, and Elazig Downtown are predicted to be shaken by rock peak ground acceleration, PGAVS30=1100 m/s, levels of 0.12–0.42 g, 0.05–0.11 g, 0.05 g, and 0.08 g respectively. The documented geotechnical field performances vary from widespread liquefaction-induced sand boils and lateral spreading, to no signs of surface manifestations of permanent ground deformations or soil liquefaction. In Battalgazi district and Elazig Downtown, the foundation performances vary from no signs of permanent ground deformations to 1–3 cm settlements, and 1–2 cm lateral movements. Additionally, the hydraulic structures inspected are estimated to be shaken by PGAVS30=1100 m/s levels of 0.03–0.23 g. Other than a minor longitudinal cracking along a limited section along the crest of a homogeneous earthfill dam, no apparent signs of permanent ground deformations were reported. Last but not least, a number of rock falls were mapped, based on back analyses of which probable peak ground velocities at these rockfall sites were speculated.

Landslide susceptibility modeling is complex as it involves different types of landslides and diverse interests of the end-user. Developing mitigation strategies for the landslides depends on their typology. Therefore, a landslide susceptibility based on different types should be more appealing than a susceptibility model based on a single inventory set. In this research, susceptibility models are generated considering the different types of landslides. Prior to the development of the model, we analyzed landslide inventory for understanding the complexity and scope of alternative landslide susceptibility mapping. We conducted this work by examining a case study of Kalimpong region (Himalayas), characterized by different types of landslides. The landslide inventory was analyzed based on its differential attributes, such as movement types, state of activity, material type, distribution, style, and failure mechanism. From the landslide inventory, debris slides, rockslides, and rockfalls were identified to generate two landslide susceptibility models using deep learning algorithms. The findings showed high accuracy for both models (above 0.90), although the spatial agreement is highly varied among the models.

Cemented paste backfill (CPB) has been widely used as local and regional underground support to reduce host rock wall closure in mined-out areas and also to reduce rockfall and rockburst incidents. However, analyzing the rock mass—CPB interactions in the first month after backfill placement must account for the CPB’s time-dependent strength, stiffness, and volume change characteristics during binder hydration. This article presents the first such comprehensive study made for CPB from the Williams mine in Ontario, Canada. Monotonic isotopically consolidated drained compressive triaxial tests were conducted on cured CPB specimens using the lubricated-ends test technique. The specimens had 3.0–7.5% Cement Content (CC); Curing Times (CTs) were from 3 to 28 days; and the confining stress ranged from 25 to 350 kPa. During shearing, all tests exhibited an initial contractive phase leading to a Characteristic State (CHS or point of volumetric strain reversal) followed by dilation with a maximum dilation rate corresponding to peak stress at the Failure State (FS). Both CHS and FS are adequately described by the Mohr–Coulomb criterion and a framework formulation was proposed to predict the evolution of CHS and FS based on CC and CT. Furthermore, the volumetric strains at CHS and FS can be defined as linear functions of the respective axial strains at the CHS and FS. Quantification of the observed behaviors through these functional relationships can help develop future constitutive models that better represent CPB’s transient response to triaxial stress loading while curing, which is essential to understanding as-placed backfill properties and its interaction with surrounding rock mass.

Soil cushion layers are commonly paved in front of protection structures to avoid the direct impact of rockfall and debris flow. This study is devoted to investigating the influence of particles size on the buffering efficiency of a soil cushion layer by experimental and numerical tests. A series of experimental tests are performed by releasing a spherical granite rock block from different heights to impact onto a soil cushion layer consisting of uniformly graded particles. The influence of particle grading on the buffering efficiency is then analyzed in a set of parametric studies. The impact force of rock block and the interacting force at the interface between the soil layer and the protection structure are monitored and evaluated. The discrete element method is utilized to explore the cratering process of rock block, together with the force chains and energy evolutions in the soil cushion layer. The results indicate that soil particles size can influence significantly on the impact force, especially for high-velocity impacts. This effect can be explained by the number and the stability of force chains formed in the granular packing. These findings can provide some insights to designing effective soil cushion layers for protection structures.

Ground control failures are one of the main causes of accidents in the underground stone mining industry. Some of the fundamental tools for rockfall hazard identification are related to rock mass characterization and geotechnical discontinuity mapping. Recent technological advances in these methods are related to remote sensing techniques and point cloud processing software for automated discontinuity mapping. Remote sensing techniques, such as LiDAR and photogrammetry, generate multi-million point clouds with millimetric precision, capturing the structure of the rock mass. The automated point cloud processing tools offer alternative algorithm-based methods to characterize and map these discontinuities. However, their applicability is constrained by multiple factors such as site specific conditions of the rock mass and the parameters used within the mapping algorithms. This paper evaluates the performance of automated discontinuity extraction software compared with manual virtual discontinuity mapping. Sampling windows from laser-scanned sections in an underground limestone mine are defined and mapped using discontinuity set extractor (DSE). Results from the virtual discontinuity software are compared with manually extracted fractures from I-Site based on reviewing orientation, trace length, spacing, number of extracted discontinuities, and processing time. The analysis determined that the automated mapping algorithm was able to identify the same discontinuity sets that had been manually mapped. The automated mapping software mapped an excessive amount of smaller fractures, which caused the comparison of both mapping techniques to be unsuccessful in terms of trace length and spacing.

Flexible rockfall barriers are commonly constructed on steep hillsides to mitigate rockfall. The evaluation of the dynamic response of proprietary flexible rockfall barriers is conventionally performed using full-scale field tests by dropping a block onto the barriers in accordance with the European test standard ETAG 027. The block typically has a spherical or polyhedral shape and cannot reproduce more complex rockfall scenarios encountered in the field. Little attention has been paid to the effects of the block shape on the impact force and structural response. This paper aims to quantitatively reveal the influence of the block shape on the dynamic response of flexible rockfall barriers. First, an ellipsoidal model is established to approximately simulate the block, and the sphericity is employed as the representative index of the block’s shape. A full-scale test on a typical flexible barrier system is carried out and then used to calibrate an advanced three-dimensional finite element model. Finally, the dynamic responses of flexible rockfall barriers are analyzed and discussed, focusing on the effects of the block’s shape. The numerical results show that the sphericity will obviously influence the maximum elongation of flexible barriers, the peak impact force, the peak force of the upslope anchor cable, the peak force of the lower main support cable, the axial peak force of the post, and the peak shear force at the post foundation. The assumption of spherical or polyhedral blocks in the test standard could lead to the defensive failure of flexible rockfall barriers in some impact scenarios.

A procedure of overall work is given for the current engineering study of the emergency section of the access transport route on seaport territory. Results of the overall engineering study is provided, and analysis is completed, on the basis of which the zones that are hazardous due to rock falls are localized. Substantiation was given, and optimal technical solutions for engineering protection of the plant were developed.

Rockfalls are a major hazard in mountain areas and along engineering slopes. It is important to fully understand the characteristics and processes of rockfall movements, both for hazard assessment and countermeasure design. This study focused on the movement characteristics and disaster processes of rockfalls by three-dimensional discontinuous deformation analysis (3D-DDA), the effectiveness of which was verified by outdoor experiments. An apparatus specifically built for the experiments was established, which included a releasing device and a binocular camera stereovision system. Blocks of three different shapes and sizes were released on slopes with three different inclinations on the campus of Tibet University. The indices of the movement characteristics of the blocks, such as lateral deviation, resting position, jumping height, and kinetic energy evolution, were investigated. The experimental results were compared with those of the 3D-DDA, so as to study the rockfall movement characteristics. On this basis, the 3D-DDA was applied to simulate a large-scale slope rockfall on the Tibetan Plateau, and the rockfall failure processes and movement characteristics were further analyzed. The results showed that the 3D-DDA method could effectively simulate the entire rockfall process in time and space, including instability and movement. Through the 3D-DDA numerical simulations, rockfall phenomena and behaviors could be fully understood. Furthermore, by analyzing the trajectories and kinetic energies of a rockfall, the prediction of rockfall disasters and the reasonable design of protective countermeasures could be realized.

The main objective of this study was to evaluate the influence of the degree of weathering on the strength properties and parameters of a kinzigite gneiss. Kinzigites are important to study do to their common occurrence in southeastern Brazil, as in the city of Rio de Janeiro, where many rock slope stability problems—such as rock falls, rockslides and debris flows—are related to the occurrence of such rocks. This manuscript presents results on the influence of weathering on the parameters of the Hoek–Brown strength criterion, which is not commonly discussed in the technical literature. Specimens of this rock type were collected from a typical weathering profile developed under a tropical climate, exhibiting four classes of alteration: sound rock (I), slightly weathered rock (II), moderately weathered rock (III) and highly weathered rock (IV). Tests were performed in accordance with methods suggested by the ISRM (The complete ISRM suggested methods for rocks characterization, testing and monitoring. ISRM Turkish National Group Ankara, Turkey, 2007). The results showed that the mi parameter of the Hoek–Brown strength criterion was clearly affected by weathering; mi was 21.31 ± 8.24 for Class I materials, 13.17 ± 2.53 for Class II materials, and 11.12 ± 7.29 for Class III materials.

A numerical analysis is validated against a Swiss Federal Commission for Technology and Innovation (CTI)—frame impact experiment conducted by the Swiss Company Geobrugg. The discrete element method is used to simulate the impacting object, while the highly nonlinear structural response is analysed with the finite element method. Both methods are coupled within an open-source multi-physics research code to exchange data and simulate the interaction. The successful practical application of the coupling algorithm is demonstrated with this work, as the numerical results show good agreement with the experimental results. Within this paper the main focus is the appropriate modelling of the impacting objects, which heavily influences the simulation results, while a simplified structural model allows a correct assessment of the global deformation behaviour and reaction forces.

The runout behavior of rockfall is mostly determined by the terrain and its mechanical parameters. The two factors can be significantly changed in a short period of time due to rockfall deposits in high-frequency rockfall regions. In this paper, a self-evolution process of rockfall from the Hongshiyan post-earthquake rock slope is observed and analyzed. This self-evolution process of the rockfall is the consequence of the re-occurrences of a large number of rockfall events in a short period of time, which lead to an increase in the elevation, slope angle, and hardness of the terrain, and aggravate further the severity of subsequent rockfall disasters. In order to analyze the self-evolution process, numerical simulations based on a probabilistic model were carried out on eight different conditions to analyze the interaction between the rockfall and different ground surface. The corresponding rockfall hazard was then analyzed according to a quantitative assessment method. The statistics of the average class (AC) and mitigation index (MI) of the rockfall were proposed to quantify the rockfall characteristics in different conditions. The effectiveness of structural and non-structural rockfall protection measures in high-frequency rockfall areas was discussed. An interim non-structural measure that addresses the self-evolution of rockfall is proposed to improve the mitigation efficiency, which can also reduce the maintenance cost.

Rockfall is a critical problem in the hilly regions. The Lengpui-Aizawl highway has witnessed many rockfalls and other types of landslide events in the past few years. This highway is imperative to the area as it links the Lengpui airport with the city. Most of the rock slopes along this highway are prone to rockfall, thus requires proper investigation. In this study, an investigation into the rockfall hazard was carried out on the nine rock slopes using the rockfall hazard rating system (RHRS) approach along NH-44A. Based on an extensive field investigation, the analysis shows that two out of nine slopes are more hazardous than the others as the RHRS score for these slopes is higher than 500. Furthermore, rockfall simulations were performed for hazardous slope to quantify the risk in terms of bounce height, velocity, kinetic energy and maximum reach of falling rock blocks. The simulation result reveals that vehicles on the roadway are under continuous threat. The potential falling blocks have a kinetic energy of 196 kJ which is enough to damage the buildings, vehicles and fatalities.

The Karakoram Highway links north Pakistan with southwest China. It passes through unique geomorphological, geological and tectonic setting. This study focused 200-km-long section of the highway starting from Besham until Chilas. Landslides are frequent and are mostly triggered by torrential rain during Monsoon and Westerlies, leading to highway blockade. Rockfall and debris flow are prime mode of slope failures. Regional to site-specific approach was implemented to assess risk associated with these two modes. Remote sensing-based techniques were used to identify potential hazardous sites, which were further investigated for risk assessment. Modified Pierson’s rockfall hazard rating system (RHRS) rated potential rockfalls, whereas semi-quantitative technique was employed to assess debris flows. Normalized scores of each site shaped the final map, further classified into four zones: very high, high, intermediate and low risk.

Rockfall is a natural hazard in mountainous areas not to be underestimated. Mass activities differing in rock volume may cause considerable economic damage. Accomplishing qualitative appraisal of high-potential zones for rockfall is a first step towards implementing mitigation strategies. Nowadays, Geographical Information Systems (GIS) are the state-of-the-art tool for a fast and economic approach of identifying potential hazard zones rather than using conventional mapping with in-situ field data. Primarily, current research focuses on designing and implementing user-friendly tools delineating potential rockfall hazard zonation (RHZ). The constructed model examines triggering factors like slope, aspect, elevation, lithology, structural lineament, rainfall intensity, and seismic activity focal depth of a mountainous coastal region (Gulf of Aqaba, Egypt). The extracted geomorphological parameters were based on a high-resolution TanDEM-X Digital Elevation Model. The enhanced Landsat ETM + 7 was used to generate the lithological and structural lineament parameters, while the rainfall data were collected from NASA project tool. The zonation model was implemented by means of ESRI’s ArcGIS Pro ModelBuilder. Google Earth Pro orthophotos compared with the generated rockfall hazard zonation map indicate the potential RHZ with high reliability. The achieved results show that 15 % of the study area qualifies as a high rockfall hazard zone. As the RHZs generated by the model depend on the input data and the selected rating scores and weights, obtaining ground truth is essential to get a trustworthy result. Finally, this study recommends employing the built RHZ model on similar terrains worldwide to support decision-makers involving any sustainable development projects.

A rock avalanche that destroyed 23 houses and killed 35 people occurred on 28 August 2017, Nayong, SW China. Combined with the dynamic parameters from seismic signal inversion, a discrete element model, MatDEM was used to determine the rock avalanche’s kinematic behavior. Although the dynamic process obtained through inversion will be disturbed by factors, such as rockfall from the source area, by comparing the velocity of rock avalanche versus horizontal distance traveled, the best combination of parameters was selected from different values given. The dynamic process obtained by modeling was compared with the nearest seismometer frequency distribution spectrum, showing that the dynamic process is in good agreement with those parameters inverted from seismic signals. The simulation results show that the movement process lasted for nearly 40 s, with a maximum speed of 40 m/s. This model of selecting parameters contributes to explain the dynamic processes of similar rock avalanche more accurately and is of great significance to the hazard prediction in the karst area.

The assessment of rock fall hazard of a natural rock slope surface with ancient rock cave monuments of historic importance at World-Heritage site of Ajanta in the state of Maharashtra in India, embedded in basaltic rock formation is carried out and presented. In past the site has witnessed many small and large scale rock falls in the form of boulders which could cause the loss to the ancient rock caves of historic importance as well as en-dangering the visitor’s safety. The main cause of the rock fall is dislocation of the boulders from the natural rock surface slopes due to heavy rainfall as well as due to erosion, rock weathering, trees roots widening etc. In the present study, the rock slope surface and dislocated boulders vulnerability to failure risk is carried out with the Rockfall Hazard Rating System (RHRS) in tandem with other empirical approaches available for rock mass classification. The study using rockfall hazard rating system requires tedious field-work due to the involvement of a large number of parameters and long-stretch of the site under question. The detailed field study is carried out for the evaluation of various parameters involved in the RHRS as well as that of various empirical approaches applied. In the case of the cumulative RHRS score is more than 500 which implies that the slope surface or critical boulder site is unstable, prone to failure and need immediate attention for remedial measures. Accordingly, stabilization measures are planned on the priority basis.

Back break is an unsolicited phenomenon caused due to rock condition, blast geometry, explosive and initiation system in mines. It does not help in creating a smooth high wall and free face for next blasting due to cracks, overhang and under-hang. It can cause rockfall during drilling due to the cracks present in the in situ rock mass at the perimeter. Due to improper free face created from the previous blast and the presence of loose strata in the face increases the overall cost of production. Therefore, predicting and subsequently optimising back break shall reduce their problems to some extent. In this paper, an attempt is made to predict back break using the random forest method. The variables used for the study was such as burden to spacing ratio, stemming to hole-depth ratio, p-wave velocity and the density of explosive. For the random forest model, R2 0.9791 and RMSE 0.87899 and for linear regression was R2 was 0.824 and root mean square error (RMSE) 0.72, respectively. From the field trials, it was evident that the use of low-density emulsion can help in reducing the back break and optimise the overall cost of the blasting process. The same results were validated using Random forest method wherein the model R2 was 0.9791 and RMSE was 0.8799.

Rockfall trajectory and kinetic energy distribution are the main components of rockfall research. In many cases, limited by site conditions, field experiments cannot be conducted adequately, so numerical simulation is necessary. This paper investigates the rockfall hazard on a slope in Yuanyang city, Dalian, China. Field experiments, ROCFALL software simulation and a secondary development simulation based on the discrete element method (DEM) were used to obtain the kinetic characteristics of ten rock blocks on four profiles. Comparing the results of two simulation methods with the field experiments shows that the DEM simulation is more accurate and comprehensive. According to the simulated trajectory and kinetic energy distribution of rockfalls, the area influenced by rockfalls is obtained, and a flexible barrier is selected as the protection measure. Therefore, DEM simulation is an effective means to study rockfall movement and can serve as the basis for the design of safety engineering.

As a key input parameter for simulating the moving trail of a rockfall, the magnitude of the normal coefficient of restitution (Rn) directly affects the prediction accuracy. However, few comprehensive and accurate calculation models are available for reference, owing to the fact that Rn is jointly controlled by multiple factors with the influence mechanisms being complex. Considering the interactive effects of influencing factors and the non-linear relationships between some influencing factors and Rn, the combined effects of the seven influencing factors on Rn were first investigated in this study by the response surface methodology–central composite design (RSM–CCD) method. The effects of the seven main factors on Rn were all significant; the results of the regression and variance analysis indicate that for non-angular blocks, the degree of influence of these factors is given by the following sequence: shape factor (η) > Schmidt hardness of the block (SHV1) > impact angle (θ) > rotational speed (ω) > Schmidt hardness of the slope surface (SHV2) > incident velocity (V) > block size (d). However, for angular blocks, the sequence is θ > SHV1 > ω > η > V > SHV2 > d. There are also many interaction parameters that had significant effects on the Rn of the test blocks (for non-angular blocks: η–θ > d–η > η–ω > V–d > SHV1–η > SHV1–θ; for angular blocks, d–θ > SHV1–d > V–η > SHV1–ω > d–η > η–ω > SHV1–η), the effects of which were examined via contour and three-dimensional surface plots. Based on the conclusions of these experiments (the determined significant influence parameters of Rn) and the previous single-factor experiments, the SPSS19.0 software was used to perform multivariate non-linear regression on the test results. Consequently, two Rn value calculation models of both non-angular and angular blocks were established. Through a contrastive analysis of the measured values of field tests and the predicted values of various models, the prediction ability of models “a” of the two types of blocks closely approached the measured values, with average deviations of only 3.4% and 9.8%; thus, these models can basically be used to achieve an accurate prediction of Rn values under various conditions. The models obtained in this study consider the comprehensive influences of various factors, which include not only the effects of all the main controlling factors, but also those of the interactions between them. Thus, these models can more accurately reflect the energy loss in the process of rockfall impact, which is helpful to improve the prediction accuracy of rockfall motion paths and is capable of providing a more reliable reference for the prevention and control of rockfall disasters.

Global warming and anticipated increase in rainfall frequency and magnitude are linked to enhanced rockfall activity worldwide. Arid environments, which currently receive limited amount of annual rainfall, will be particularly subject to frequent and unpredictable rockfall activity that can substantially jeopardize human lives and infrastructures. The main scope of this study is to assess the rockfall hazards in Thawr Mountain and Al-Azyziah district, western Saudi Arabia, using integrated field, geological, climatological and remote sensing datasets and modeling. Our findings indicated that: (1) there are general increasing trends of average annual precipitation and temperature for the period between 2009 and 2019, (2) inspection of multi-temporal satellite images between 2003 and 2017 showed rapid urban expansion, mainly through modification of hillslopes for urban development, which is expected to pose critical consequences on slope instability, (3) field investigations attributed rockfall activity to weathered exfoliated granodiorite hillslopes with abundant tension cracks and steep slopes, (4) slope degrees reached 79° with a general slope direction toward the urbanized areas, and (5) the rockfall motion was simulated along six profiles with dynamic urban areas along the termination of each profile, which showed that several blocks along the six profiles can reach the profile termination with medium intensity rockfall activity and kinetic energy ranges between 50 and 80 kj. The reported rockfall motion can threaten lives, houses and infrastructures. Therefore, protective precautions were suggested to prevent and mitigate the impact of rockfall activity along the studied profiles and similar areas in the mountainous western Arabian Peninsula.

Rockfalls are one of the most common instability processes in high mountains. They represent a relevant issue, both for the risks they represent for (infra) structures and frequentation, and for their potential role as terrestrial indicators of climate change. This study aims to contribute to the growing topic of the relationship between climate change and slope instability at the basin scale. The selected study area is the Bessanese glacial basin (Western Italian Alps) which, since 2016, has been specifically equipped, monitored and investigated for this purpose. In order to provide a broader context for the interpretation of the recent rockfall events and associated climate conditions, a cross-temporal and integrated approach has been adopted. For this purpose, geomorphological investigations (last 100 years), local climate (last 30 years) and near-surface rock/air temperatures analyses, have been carried out. First research outcomes show that rockfalls occurred in two different geomorphological positions: on rock slopes in permafrost condition, facing from NW to NE and/or along the glacier margins, on rock slopes uncovered by the ice in the last decades. Seasonal thaw of the active layer and/or glacier debutressing can be deemed responsible for slope failure preparation. With regard to timing, almost all dated rock falls occurred in summer. For the July events, initiation may have been caused by a combination of rapid snow melt and enhanced seasonal thaw of the active layer due to anomalous high temperatures, and rainfall. August events are, instead, associated with a significant positive temperature anomaly on the quarterly scale, and they can be ascribed to the rapid and/or in depth thaw of the permafrost active layer. According to our findings, we can expect that in the Bessanese glacierized basin, as in similar high mountain areas, climate change will cause an increase of slope instability in the future. To fasten knowledge deepening, we highlight the need for a growth of a network of high elevation experimental sites at the basin scale, and the definition of shared methodological and measurement standards, that would allow a more rapid and effective comparison of data.

On Friday, January 24, 2020 at 20.55:11 local time (17:55 UTC), an earthquake with a magnitude of Mw = 6.8 has occurred in Sivrice district of Elazig (Eastern Turkey). Focal mechanism solution is consistent with pure left-lateral strike-slip faulting; the location of the epicenter and fault mechanism suggest deformation along the Puturge segment of the East Anatolian Fault Zone. A 10-day fieldwork was carried out along the Puturge segment to study surface deformation; the geometry of the surface rupture and other seismic geomorphological structures were mapped and studied in detail. The field data are also correlated with satellite images. This paper, therefore, presents classification of seismic geomorphological structures and discuss intimate relationship between fault geometry and stress field in the region. Seismic geomorphological deformation and related features of the Sivrice (Elazig) earthquake are observed in the area between Gezin (Elazig) and Ormanici (Puturge) villages; they are classified into two as seismotectonic and seismo-gravitational features. Field observations confirm that seismo-gravitational structures develop along both Gezin-Sivrice–Doganbagi and Doganbagi–Cevrimtas–Ilincak–Koldere–Ormanici sections of the Puturge segment, while surface rupture is mapped as seismotectonic structure only along the Doganbagi–Cevrimtas–Ilincak–Koldere–Ormanici section. Small-scale landslides, rock falls, feather cracks along asphaltic roads, and laterally discontinues ground failure-related features are common seismo-gravitational structures that developed along the fault zone. In addition, small-scale lateral spreading and liquefaction structures are common especially in areas where fault-perpendicular streams meet the Karakaya Dam reservoir. The surface rupture is mapped as stepping and overlapping en echelon fractures along elongated pressure ridges between Cevrimtas and Doganbag villages, to northwest of Ilincak village, along 1.5-km-long pressure ridge between Topalusagi and Doganyol, across the elongated hill that developed on an alluvial fan to the northwest of Doganyol and in the area between Koldere and Ormanici villages. Surface fractures deforming the pressure ridges are all aligned parallel to the long axes of the ridges and display reverse components that give rise to small-scale pop-up structures. Interferometric SAR (DInSAR) studies indicate a 10-cm uplift in the northwestern block of the fault and a 6-cm subsidence in the southeast block. The difference in vertical movements between two blocks of the fault is interpreted to suggest that at least 30-km-long section of the Puturge segment in the area between southwest of Sivrice and Puturge is broken during the main shock. Although the focal mechanism solution of the main shock gives pure left-lateral strike-slip faulting, there is no significant left-lateral displacement observed during the fieldwork. This can be explained by the following: (1) left-lateral strike-slip displacement was not able to reach the surface; (2) left-lateral torque movement of the fault around a vertical axis during the earthquake, (3) restraining bend nature of the Puturge segment, or (4) the presence of Puturge metamorphics along the fault strike. It is also important to note that along most part of the Puturge segment where surface rupture is observed, talus, colluvial or alluvial fan sediments are exposed; unconsolidated and/or poorly consolidated nature of these sediments may also be counted as one of the main reason for not observing horizontal displacement on the surface. When we compare these surface deformations with the surface ruptures that occurred in the last 100 years in Turkey, we suggest that the formation of the surface deformations is variable depending on: (1) the fault type and the state of regional stress, (2) the magnitude of the earthquake, (3) the duration time of the earthquake and (4) the geomorphologic feature of landscape in relation to the lithologic and structural features of the rock units along the active fault zone.

A growing body of research indicates that rock slope failures, particularly from exfoliating cliffs, are promoted by rock deformations induced by daily temperature cycles. Although previous research has described how these deformations occur, full three-dimensional monitoring of both the deformations and the associated temperature changes has not yet been performed. Here we use integrated terrestrial laser scanning (TLS) and infrared thermography (IRT) techniques to monitor daily deformations of two granitic exfoliating cliffs in Yosemite National Park (CA, USA). At one cliff, we employed TLS and IRT in conjunction with in situ instrumentation to confirm previously documented behavior of an exfoliated rock sheet, which experiences daily closing and opening of the exfoliation fracture during rock cooling and heating, respectively, with a few hours delay from the minimum and maximum temperatures. The most deformed portion of the sheet coincides with the area where both the fracture aperture and the temperature variations are greatest. With the general deformation and temperature relations established, we then employed IRT at a second cliff, where we remotely detected and identified 11 exfoliation sheets that displayed those general thermal relations. TLS measurements then subsequently confirmed the deformation patterns of these sheets showing that sheets with larger apertures are more likely to display larger thermal-related deformations. Our high-frequency monitoring shows how coupled TLS and IRT allows for remote detection of thermally induced deformations and, importantly, how IRT could potentially be used on its own to identify partially detached exfoliation sheets capable of large-scale deformation. These results offer a new and efficient approach for investigating potential rockfall sources on exfoliating cliffs. Electronic supplementary material The online version of this article (10.1007/s10346-020-01524-1) contains supplementary material, which is available to authorized users.

Slope dynamics in volcanic environments comprise a wide spectrum of phenomena, from large lateral collapse to shallow debris remobilization, which may represent a major threat for human communities and infrastructures. Many volcanos built up from the ocean floor and large portions of the volcano edifice are submerged. In these settings, only the edifice's summit can be investigated by terrestrial remote sensing and in-situ approaches. Growth and destruction, including tectonics and gravitational phenomena, affect entire volcano flanks and are not limited to the physical boundary of the sea level but could comprise their subaqueous parts

A high-position destructive rockfall, significantly influenced by post-seismic effect of Wenchuan earthquake in 2008 and associated aftershocks, was reported in Miansi Town of Wenchuan County, Sichuan Province, China. About 3,000 m3 of rock at high position detached from a dipping rocky slope, which manifested as a translational motion. Detailed field investigation, geological mapping, kinematic analysis, and numerical modelling are presented to comprehensively analyze the complex failure mode of the post-seismic rockfall. The results demonstrated that the sliding surfaces are mainly controlled by the internal shear discontinuity sets. The backscarps are progressively evolved from the tensile cracks at rear slopes caused by the Wenchuan earthquake. Because of the combination effect of heavily shocks of previous earthquake and local geomorphology of the rockfall with beneficial for facilitating the magnification effect on peak ground acceleration (PGA), the rock mass of slopes is dramatically damaged and fractured. The original intact slopes finally developed to the shattered slopes as an optimum birthplace for the post-seismic rockfalls. It should be noticed that intensive precipitation plays a triggering factor that generates the hydrostatic water pressure in the rear cracks and the uplift pressure at the bottom sliding surface within a short time. The evolution processes are divided into three stages: slope relaxation stage, rock shattering and disaggregation stage, and high-speed falling stage. Velocities, energy, and bounce heights of falling rock blocks are computed by the RocPro3D software for understanding the corresponding kinematics. The paper can provide an insight into post-seismic rockfalls in the tectonic areas associated with the combination of seismic activities and intense rainfall.

Forests below rocky cliffs often play a very important role in protecting settlements against rockfall. The structure and development of these forests are expected to be substantially affected by the disturbance of the falling rocks. Knowing about this effect is important to predict the development of protection forests and consider potential effects of the falling blocks in management strategies. The goal of this study is to quantify differences in forest structure depending on rockfall activity in four different sites in the Swiss Alps. For this, we collected data on forest structure in zones of different rockfall activity and derived rockfall impact probabilities based on rockfall simulations. We assessed whether differences in forest structure and signs of rockfall disturbance could be observed between the rockfall zones. We additionally built mixed-effects models to identify the key variables explaining the forest characteristics described by diameter (DBH) and basal area (bA). The forest structure differs between the rockfall zones, however, with varying effects amongst the sites. DBH tends to decrease with increasing rockfall activity, whereas tree density appears to be little impacted by rockfall. For most sites, the number of deposited blocks and the simulated tree impact probability have a significant effect in the models along with the species, whereas for one site, hardly any effect of rockfall was found. Our results, obtained either from direct measurements or modelling, show that rockfall can locally influence the structure of forests, whereas the influence depends on the frequency and intensity of the rockfall disturbance. Impact probabilities obtained by simulations can serve as a good proxy for rockfall disturbances.

The winding Dasha River section of the Central Cross Island Highway in Taiwan is 9.44 km long. More than 20% of its length has been rerouted in the past six decades due to landslide-induced maintenance problems. To investigate the influence of geological conditions on the maintenance of this mountainous road section, this study establishes inventories of highway alignments and nearby landslides based on interpretations of multi-temporal aerial photos and highway maintenance records. Types of landslide and topographic features are verified through field investigation, and the engineering characteristics of rock masses are evaluated using the Q-method semi-quantitatively. The results reveal that three sections with rerouting of road or structural modification are located near the undercut slopes of the Dasha River and the boundaries of strata where water erosion and scouring are active and considerable gullies develop. Various metamorphic strata with intricate folds are formed by orogenic deformation and metamorphism under the influence of weathering, such as water erosion and scouring; these evolve into meanders and steep slopes. Gullies develop along the boundaries of strata with distinct lithology, where the engineering characteristics of rock masses vary markedly, disturbing the stability of nearby slopes and hindering the maintenance of the mountain road for long periods. Rerouting the highway and the use of a tunnel instead of the slope-cut-in halfway road effectively mitigate the influence of landslides near meanders where water erosion and scouring are significant. A gallery tunnel effectively mitigates rock fall. However, a gallery tunnel must be constructed without causing overcut-induced slope instability.