In 1968 a road was constructed along the coast on the western side of the Tröllaskagi peninsula in central north Iceland. The road, which until 2010 was the only whole year road to the town of Siglufjörður, crosses three large landslides, the Hraun landslide in the south, the Þúfnavellir landslide and the Tjarnardalir landslide in the north, in an area named Almenningar. Since its construction extensive damages have occurred on the road often causing hazardous conditions.
In 1977 the Icelandic Road and Coastal Administration began to monitor the deformation. In the beginning the measurements were achieved with several years intervals, but over the last decades yearly measurements have been carried out. In the year 2022, nine GNSS stations were installed along the road and a rain gauge, giving us for the first time the possibility of 24/7 monitoring on the displacements and connect the movement to weather variations, such as temperature variation and precipitation.
The dataset, which spans now over 47 years, gives us a unique opportunity to correlate the displacements on the road to external factors. Written source of deformation in the Almenningar area dates back to 1916 and since then more than 50 movement events have been listed affecting the road.
These measurements show the deformation along the road, but recent studies using “feature tracking” and InSAR show us that the whole landslide masses show signs of movement.
Our studies show that the highest movement rate takes place along the frontal parts of the landslide masses and that the movement is strongly related to both weather variations, e.g. precipitation, snowmelt and coastal erosion.
How to cite: Sæmundsson, Þ. and Geirsson, H.: Interaction between weather variations and large scale displacements along the Siglufjarðarvegur road in the Almenningar area, in central North Iceland, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8775, https://doi.org/10.5194/egusphere-egu25-8775, 2025.
The reactivation of earthflows in fine-grained geological media represents a complex phenomenon characterised by transitions from prolonged dormant phases to sudden accelerations. While dormant stages typically exhibit slow movements (less than 1 m/year), critical rainfall conditions may trigger rapid surges in which the landslide mass can attain velocities up to several meters per hour within a limited time frame. Despite the extensive literature on the subject, the mechanisms and dynamics underlying this peculiar behaviour remain incompletely understood, largely due to challenges in acquiring direct field data that accurately capture these episodic events.
This study presents field data documenting the October 2024 reactivation of the large, dormant Ca’ di Sotto earthflow, located in the Northern Apennines (Italy) within the municipality of San Benedetto Val di Sambro. During the initial stages of reactivation, adverse weather conditions, including persistent fog and rainfall, severely hindered direct visual observation and aerial monitoring of the landslide's evolution. To overcome these challenges, a GNSS-based monitoring system was promptly deployed, comprising 31 evenly distributed periodic measuring points (surveyed daily) as well as three dual-frequency permanent GNSS stations.
GNSS data revealed an exceptionally rapid reactivation of the Ca’ di Sotto earthflow. The initial failure quickly propagated from the source area through the entire 2-km-long landslide body within a few days irreversibly compromising the functionality of a water bypass system built at the toe of the earthflow along the Sambro Stream after a previous reactivation in 1994. The failure of this bypass caused a critical water level rise in an upstream impoundment that had formed during the 1994 event.
In the following weeks, as precipitations significantly subsided, the landslide mass progressively decelerated, transitioning from peak velocities of 100 – 150 m/day recorded during the initial phase to rates of a few cm/day. At this stage, the monitoring system was enhanced with periodic drone surveys and a robotic total station, providing hourly measurements with millimetric precision across 24 regularly distributed monitoring prisms. Particularly, two transverse prism arrays were strategically installed at different elevations to serve as early warning systems for potential future reactivations.
Additionally, emergency hydraulic risk assessments were conducted, examining plausible scenarios of river blockage, impoundment water level fluctuations and management with contingency water pumping systems. These scenarios were evaluated considering ad hoc impoundment characteristic curves and hydrographs derived for design rainfall events, following the standardised NRCS (Natural Resources Conservation Service) unit hydrograph methodology.
How to cite: Zuccarini, A., Ciccarese, G., Dal Seno, N., Bartola, M., Rani, R., Zamboni, L., Caputo, G., Carboni, R., Fantini, A., Monti, L., and Berti, M.: Field monitoring of the recent reactivation of the large dormant Ca’ di Sotto earthflow, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6962, https://doi.org/10.5194/egusphere-egu25-6962, 2025.
In Nepal, efforts to establish landslide-triggering rainfall thresholds across multiple scales are well underway, aiming to enhance the effectiveness of landslide early warning systems (LEWS). These thresholds are being developed at regional, provincial, municipal, and single-slope levels, supporting landslide prediction across diverse geographic and administrative contexts.
In the vast and landslide-prone Himalayan region, establishing a regional rainfall threshold is crucial. Analysis of historical data from 1951–2006 covering 677 landslides identified a threshold relationship between rainfall intensity and duration, revealing that daily precipitation exceeding 144 mm significantly increases landslide risk. This regional threshold, developed by Dahal and Hasegawa (2008), serves as a valuable basis for early warnings across the Nepal Himalaya, providing essential risk management information for large-scale events.
Landslides in Nepal are frequently triggered by high-intensity rainfall, seismic activity, and hillside modification. A study using satellite rainfall data and landslide records from 2011 to 2022 developed a provincial-level threshold for Bagmati Province. The threshold equation at a 5% non-exceedance probability indicates that even low rainfall levels can trigger landslides due to geological weaknesses, particularly following the 2015 Gorkha Earthquake. This provincial threshold has been validated through real-time analysis, establishing a robust foundation for LEWS of Bagmati Province.
At the municipal level, rainfall thresholds have been developed for Helambu and Panchpokhari Thangpal municipalities. Using inventory data, intensity-duration threshold equations were established with high accuracy, showing strong predictive capability for landslides in these areas. The correlation between landslide susceptibility and terrain features underscores the importance of localized LEWS and community awareness initiatives to improve response during intense rainfall events.
On a single-slope scale, a physically based model was used to establish a landslide threshold for a slope on the Narayangadh-Mugling road. Here, variations in pore water pressure were analyzed under different rainfall return periods, revealing that increased topographic hollow size amplifies pore water pressure, which elevates landslide risk. The slope at Nau Kilo, with an extremely low safety factor, is highly susceptible to collapse during heavy rainfall, underscoring the need for targeted monitoring and stabilization at high-risk sites.
Developing these multilevel rainfall thresholds, tailored to Nepal’s diverse landscapes, provides essential tools for advancing LEWS and reducing landslide impacts on vulnerable communities. Enhancing rain gauge density, ensuring consistent landslide data management, and refining thresholds continuously will further improve prediction accuracy, offering valuable insights for disaster preparedness and community risk reduction across landslide-prone areas of Nepal.
How to cite: Dahal, R. K.: Multi-Scale Rainfall Thresholds for Landslide Prediction: Advancing Early Warning Systems in Diverse Landscapes of Nepal, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-276, https://doi.org/10.5194/egusphere-egu25-276, 2025.
Early detection and monitoring of rock slope instabilities are critical due to their sudden onset and significant risks to life and infrastructure. Understanding the factors controlling the dynamic evolution of rock slopes towards catastrophic failure remains a major challenge as mechanisms driving the failure occur at depths inaccessible to surface-based measurement techniques.
Once rock bridge failures grow and coalesce to a continuous failure plane under (sub)critical stress, a rockslide enters the mobilisation phase. From then, it creeps or slides until it evacuates the source area. For many hillslope instabilities, it is unclear how the interplay between internal mechanisms and external, often meteorological drivers governs the time to collapse and the extent of structural damage during displacement.
In Brienz/Brinzauls, Switzerland, near-field seismic data from a network of geophones and broadband sensors captured precursory signals originating on or within the active “Insel” compartment of a large landslide complex, as it accelerated from 50 mm/day in late April to over 5000 mm/day, before its collapse on 15 June 2023. During prolonged mobilisation, we analyse the link between precipitation and internal mechanisms and assess how these internal processes independently drive the unstable rock mass to catastrophic collapse in the absence of external meteorological forces.
We apply a supervised XGBoost machine learning model based on seismic features to detect and classify surface rockfall events and sub-surface micro-earthquake events (internal rock bridge failures and basal stick-slip) from continuous seismic time series.
Initial increases in surface and sub-surface event rates were rainfall-driven, with sub-surface event spikes lagging behind surface events due to progressive water infiltration into the landslide mass. After rainfall ends, surface event rates decrease earlier than sub-surface event rates as water drains from the landslide mass. Rocksliding transitioned to a phase of internal control, leading to the nonlinear evolution of surface and sub-surface events until the main collapse, in the absence of rainfall. After the transition, subsurface activity accelerated without a corresponding change in rockfall activity. Rockfall activity from the "Insel" increased after a 9-day lag, likely driven by the upward propagation of stress imbalances caused by an enhanced rate of basal sliding. A continuous decrease in sub-surface events per unit slip indicates rate-weakening behaviour at the sliding surface with slip progressively eroding asperities, reducing frictional resistance. In this context, the disintegration of rock fragments along the sliding surface generates transient families of repeating seismic events characterized by near-identical waveforms.
Our observations underline the critical role of dynamic roughness evolution at the sliding interface in governing rock mass mobilisation, with the transition from meteorologically driven sliding to internally controlled acceleration predominantly reflected in basal stick-slip and internal cracking, rather than surface rockfall activity. This highlights the need for spatially extensive monitoring of rock-internal processes to understand the non-linear dynamics of large slope instabilities during failure preparation, beyond precipitation-based models.
How to cite: Dash, S., Dietze, M., Zhou, Q., Makus, P., Walter, F., Fulde, M., Turowski, J., and Hovius, N.: Seismic precursors reveal the role of internal processes in driving mobilisation of the 15th June 2023 Brienz/Brinzauls Rockslide, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7312, https://doi.org/10.5194/egusphere-egu25-7312, 2025.
Understanding particle fragmentation and its resulting particle-size distribution is crucial for interpreting shear zone behavior in geological processes like faulting and landslides, especially under high-stress conditions. This study uses the 3-D fractal dimension (D3) to measure particle-size distribution and potential self-similarity. While previous models predict D3 values around 2.58 or 3.0, field data show significant variation. We conducted rotary shear experiments to investigate how D3 evolves with shear displacement under different normal stresses, velocities, and mineral compositions. Our results show that D3 increases monotonically with shear displacement, converging to an ultimate value highly dependent on mineral composition, but much less affected by normal stress and shear velocity. A modified large-strain model incorporating size-dependent grain-breakage probability is proposed, which explains the divergence of D3 from previous predictions. This model highlights the complexity of particle fragmentation in dense grain flows and provides a possible explanation for the high but variable D3 observed in natural shear zones. Further, we acknowledge that additional mechanisms, such as abrasion and grinding, can further contribute to particle size reduction. This study offers valuable insights into the dynamics of particle fragmentation in geological shear zones.
How to cite: Ge, Y., Hu, W., and Li, Y.: Fractal Dimension Evolution in Dense Granular Flows: Insights from Rotary Shear Experiments, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3981, https://doi.org/10.5194/egusphere-egu25-3981, 2025.
Determining the shear-velocity dependence of dry granular friction can provide insight into the controlling variables in a dry granular friction law. Scattered laboratory 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 m/s - 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, and we discussed 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 formed by spalling at high shear velocities, creating ~20 µm diameter impact pits on particle surfaces. This study provided laboratory laws of a friction-velocity (μ-v) model for granular materials.
How to cite: hu, W.: Variation in granular frictional resistance across nine orders of magnitude in shear velocity, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4620, https://doi.org/10.5194/egusphere-egu25-4620, 2025.
The importance of erosion processes in influencing the long-distance travel of geophysical mass movements (such as debris flows, rock and snow avalanches, and landslides) is well recognized. However, numerical modeling of these processes remains difficult and is frequently overlooked. Typically, researchers have neglected entrainment or employed empirical models, where the entrainment parameters must be back-calculated to achieve the observed erosion volume and runout. Instead, in this work, we use a two-phase depth-resolved model, within an elasto-plastic framework, utilizing a dilatant Mohr-Coulomb constitutive model based on Terzaghi's effective stress principle. This model effectively captures large deformations and the interactions between solid and liquid phases in water-saturated soils subjected to overriding granular flows. Consequently, it naturally simulates bed liquefaction—the transition of initially solid soil into a liquid-like state—when overridden by debris material. The simulations reveal that the initial characteristics of the bed material, such as its permeability and consolidation degree, are crucial in influencing pore pressure generation and dissipation, degree of bed material mobilization and flow travel distance, consistent with observations from natural events. The study highlights the need to consider ground hydrological and geotechnical properties when predicting landslide hazards while also offering a detailed quantitative analysis of how bed mechanical properties influence the potential for liquefaction. Since bed material properties can potentially be measured through laboratory and field tests, the two-phase depth-resolved model has the capabilities to predictively simulate real events.
How to cite: Vicari, H., Tran, Q.-A., Metzsch, M., and Gaume, J.: Two-phase depth-resolved numerical model captures debris flows entraining water-saturated sediments, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6888, https://doi.org/10.5194/egusphere-egu25-6888, 2025.
Water plays a crucial role in the initiation and runout patterns of most landslides. Variations in the degree of saturation and porewater pressure influence the strength of landslide materials, thereby determining the final runout for a given topography. These properties can vary within a single landslide body, leading to different movement patterns and mobility across different sections, with associated implications for the landslide hazard and risk. This complexity poses challenges for numerical modelling aimed at accurately predicting landslide runout.
In this study, we used Material Point Method—a hybrid Lagrangian-Eulerian method—coupled with mixture theory (Tampubolon et al., 2017) to simulate elastoplastic deformation and runout behaviour of the landslide body. To better capture the evolution of movement patterns with minimal manual constraints and to enhance the accuracy of runout predictions, we integrated an excess pore pressure generation curve (Wang, 1999) into the computational workflow. This allowed us to simulate the excess pore pressure induced by the negative dilatancy of the solid phase under conditions of rapid motion or low permeability. The integration of this mechanism captures the effects of dilatancy, which arise from compaction and grain crushing in the sliding zone during the runout process. We show that by accounting for this localised material strength loss and the pore pressure dissipation, the evolution of landslide movement and landslide runout may be more accurately simulated.
The model was validated against a two-dimensional cross-sectional slope failure scenario with varying permeability conditions. Subsequently, it was applied to two typical multi-pattern landslide cases: a giant loess landslide on the Qinghai-Tibet Plateau and another one in London Clay on the northern shore of the Isle of Sheppey. The initial state of the slope was reconstructed based on pre-landslide digital elevation model data, while the groundwater variations, driven by either rainfall or tidal influences, were modelled as the triggering factors. This approach effectively captures the localised pore pressure effects, thereby improving the accuracy of runout distance and area predictions. We expect our model to be broadly applicable to improve runout simulation and associated hazard assessment for a broad range of hydrologically modulated landslides.
How to cite: Chen, Y., Van Wyk de Vries, M., and Wang, F.: Improved landslide runout prediction by integrating the pore pressure response to dilatancy, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12359, https://doi.org/10.5194/egusphere-egu25-12359, 2025.
Erosion can tremendously amplify the volume and destructive potential of mass flows with spectacularly increased mobility. However, the mechanism and consequences of erosion and entrainment of such flows are still not well understood as these processes are inherently complex due to the composition of the flow as well as the erodible bed material and their physical properties. Erosion rate, erosion velocity, and momentum production are the key factors essentially controlling all the processes associated with erosive mass transport. Here, we present experimental results on the dynamics of impact-induced mobility of erosive mass flows. Experiments are conducted at the Laboratory Nepnova – Innovation Flows in Kathmandu using some native Nepalese food grains as well as geological granular materials. As we focus on erosion in the inclined channel, transition, and run-out zone, we determine how the flow and the bed conditions control the erosion rate, erosion velocity, and momentum production. This includes the change in volume, composition, and physical properties of the released mass and the erodible bed and its slope. We establish some quantitative functional relationships among the erosion rate, the erosion velocity, and the mobility of the mass transport aiming at providing a foundation for developing predictive models and innovative strategies for erosion control and mitigation from landslide hazard.
How to cite: Tiwari, C. N., Dangol, B. R., Kattel, P., Kafle, J., and Pudasaini, S. P.: The dynamics of impact-induced erosive mass flow mobility, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14875, https://doi.org/10.5194/egusphere-egu25-14875, 2025.
Earth dams, either natural or developed as part of mining operations (tailing dams) are prone to failure. In particular, recent studies show that tailing dams have a worldwide failure rate close to one collapse per year [1].
In this work we present the developments done in the monitoring and risk assessment for dams; including sensor technology, real-time numerical modelling and safety factor calculation. The recent surge in the availability of sensors allows enhancing the data that can be gathered to monitor the mechanical and hydraulic state of the dams. Numerical models can be used to enrich the local information collected by the sensors (e.g. piezometers, inclinometers) and provide the current physical state of the dam.
For monitoring purposes, numerical models are only useful if they provide results fast enough to react to an unsafe state. The results presented include the works of [2] and [3], where model order reduction techniques are applied in the context of data assimilation to learn about the state of dams. A transient nonlinear hydro-mechanical model describing the groundwater flow in unsaturated soil conditions is solved using Reduced Basis method. Hyper-reduction techniques (DEIM, LDEM) are tested and show time gains up to 1/100 with respect to standard finite element methods.
REFERENCES
[1] Clarkson, Luke, and David Williams. "Critical review of tailings dam monitoring best practice.International Journal of Mining, Reclamation and Environment, 34.2: 119-148, doi:10.1080/17480930.2019.1625172, 2020.
[2] Nasika C., P. Díez, P. Gerard, T.J. Massart and S. Zlotnik. Towards real time assessment of earthfill dams via Model Order Reduction. Finite Elements in Analysis & Design, Vol. 199, 103666, doi:10.1016/j.finel.2021.103666, 2022.
[3] Nasika C., P. Díez, P. Gerard, T.J. Massart and S. Zlotnik. Discrete Empirical Interpolation for hyper-reduction of hydro-mechanical problems in groundwater flow through soil. Journal for Numerical and Analytical Methods in Geomechanics, doi:10.1002/nag.3487, 2022.
How to cite: Zlotnik, S., García-González, A., Díez, P., and Massart, T.: Monitoring and real time risk analysis of earth dams, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11221, https://doi.org/10.5194/egusphere-egu25-11221, 2025.
During extreme rainfall, large-scale landslide is a frequent mishap in mainstream and tributaries of Taiwan. Reviewing the histories of Taiwan landslide events, as a large-scale rock/soil mass of simultaneous movements in mountains roads, villages, valley sides, it might cause serious disasters. Reviewing the present literatures, there are morphological indications that the potential rockslide can be track and find. Especially, the slate slope is influenced by weathering and gravitation for a long time, it become weak and it may cause the sliding slope creep and folding rock that will become the sliding surface of deep-seated rockslide. But analysis of earthquake and rainfall induced rock slope deformation, development of cracks on cliff top, failure for disaster preparedness, and response planning are sometimes inadequate due to the complexity of such slopes. Whereas, this study formulates three years that mainly focus on the failure trend of large-scale landslides for slate (or argillite) slope caused by the adjacent anticline structure. The study area was selected D077 large-scale landslide (The landslide volume is approximately 5.9 million cubic meters) case which to discuss the landslide mechanism, monitoring, and scenario simulation model. Base on the past events of the rockslide, the geological investigation, morphological analysis and remote sensing technology will helpful to induce the geological characteristics and the morphological evolution. Then, calibrated numerical methods adopted in the small-scale model were used to simulate the full-scale model. The scenario simulation results should be as close to reality as much as possible. Finally, D077 large-scale landslide case will be simulated, establishing a landslide scenario simulation model, and the results can provide reference for disaster prevention, mapping and interpretation of monitoring signals with hazard areas, and associated renovation project planning.
Key words: large-scale landslide, slate slope, anticline, monitoring, scenario simulation model.
How to cite: Lo, C.-M. and Wu, Y.-C.: Study on the landslide mechanism, monitoring, and scenario simulation of slate slopes caused by adjacent anticline structure, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2389, https://doi.org/10.5194/egusphere-egu25-2389, 2025.
Rock slope toppling typically occurs in slopes with steep, deep-seated discontinuities and involves large unstable rock masses that may transform into catastrophic secondary failures. Understanding the long-term weakening processes of such slopes remains challenging due to limited subsurface access and the lack of continuous deformation monitoring under diverse external forcings. To address these limitations, this study implements a comprehensive, tunnel-based multi-parameter monitoring system in the toppling zone intersected by the first 500 meters of the Bedretto Tunnel in Ticino, Switzerland.
The system integrates high-resolution (~0.5 m) distributed fibre optic sensors for strain and temperature monitoring along the tunnel with GPS measurements of 3D surface displacements. In-tunnel hydraulic sensors installed, in both stable and critical zones, continuously capture changes in pore water pressure, tunnel inflow dominated by fractures, and groundwater origins through high-frequency recordings of pressure, temperature, and electrical conductivity. Meteorological stations at the slope toe and toppling crown measure rainfall, air temperature, snow depth, and humidity. Complementary manual snow water equivalent measurements support a degree-day model to estimate surface infiltration onsets and volumes.
Initial results from early 2024 suggest that structural orientation primarily controls deformation patterns. While reversible strain correlated with periodic temperature fluctuations is evident, strain variations become more dynamic after precipitation events, particularly intensified in the highly fractured ductile hinge zone. These observations are reinforced by hydrological evidence, which shows gradual seasonal inflow trends near toppling boundaries punctuated by intermittent inflow spikes in response to rainfall and snowmelt events. The findings provide insights into the coupled hydromechanical and thermomechanical processes driving damage accumulation within large toppling slopes. Long-term data collection and integration with historical records aim to pinpoint the primary drivers of deformation variability. As data monitoring efforts continue and more weather events are captured, the results will support the development of modelling toppling failure evolution and contribute to a deeper understanding of rock slope weakening mechanisms.
How to cite: Yuan, M., Aaron, J., Hirschberg, J., de Palézieux, L., Rinaldi, A. P., and Edme, P.: Capturing Rock Damage and Environmental Forcings in Toppling Slopes: An Integrated Monitoring System in Bedretto, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9131, https://doi.org/10.5194/egusphere-egu25-9131, 2025.
The entire Joshimath township, located in the Chamoli district of the Garhwal Himalayan region of Uttarakhand state in India, is situated on deep-seated landslides (DSLs) and is therefore prone to intermittent creep over decades. Since October 2021, accelerated surface movements localized along the DSLs have been reported. This has damaged 868 buildings and displaced nearly 1,000 people, while also damaging roads, pipelines and other infrastructure in Joshimath, and disrupting tourist revenues. Deep-seated landslides (DSLs) in high mountain regions therefore pose a significant threat to people and infrastructure and some of these landslides are capable of transforming into catastrophic failure, similar to rock avalanches. This study hence focusses on identifying and assessing the impact of DSL acceleration, on the vulnerability of buildings exposed to DSL activity in Joshimath town. For this purpose, the vulnerable areas and infrastructure are first identified based on acquired building damage data and field studies. Next the intensity of DSL activity is determined for the identified vulnerable areas/building aggregates, using satellite-based interferometric synthetic aperture radar (InSAR) techniques, which have proven to be a cost-effective method for long-term displacement monitoring over the past decades, especially in inaccessible remote regions. Therefore, this study identified vulnerable areas/building aggregates affected by accelerated DSL activity in Joshimath, and classified these exposed areas based on damage severity, resulting in an equivalent damage severity (ED) map. The equivalent cumulative displacement (ECD) was calculated for each vulnerable area under a defined damage severity level and presented as an ECD map, derived using InSAR velocities. Finally, the empirical fragility and vulnerability curves are developed for building aggregates and vulnerable areas susceptible to DSLs activity in Joshimath. These curves facilitate a quantitative assessment of potential damage and can be used as valuable tools for planning effective risk mitigation strategies for DSL activity in Joshimath town.
Keywords: deep-seated landslides (DSLs); interferometric synthetic aperture radar (InSAR); vulnerability; equivalent damage severity map (ED); equivalent cumulative displacement (ECD)
How to cite: Lakhera, S., Jaboyedoff, M., Derron, M.-H., Peduto, D., Dehls, J., Aslan, G., Nicodemo, G., and Goswami, A.: Vulnerability Assessment of Buildings Exposed to Deep-seated Landslide Activity in the Joshimath town of Chamoli, Uttarakhand, India, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18213, https://doi.org/10.5194/egusphere-egu25-18213, 2025.
The expansion of offshore renewable energy infrastructure is critical for achieving net-zero carbon targets. However, submarine landslides pose a significant threat to power transmission cables, pipelines, and other linear infrastructure, with high associated economic and operational risks. To address this challenge, we present a novel geotechnical centrifuge model that evaluates the impact of submarine landslides on flexible obstacles. The experimental setup features a tilting mechanism to induce slope failure, simulating landslides in an enhance-gravity scaled environment. The soil material comprises glass beads, and the impacted obstacle is a cylindrical element spanning the centrifuge box transversely. The cylinder, designed to slide laterally upon impact, mimics the flexibility of cables and pipelines lying on the seafloor. An external spring system connected to the cylinder adds resistance, also allowing precise reconstruction of soil-forces and their evolution over time. Both submerged and dry conditions are explored. Preliminary results highlight the influence of obstacle flexibility on force attenuation and displacement patterns. These insights contribute to the understanding of flow-structure interaction in submarine landslides, necessary to update guidelines on impact loads, and providing a foundation for resilient offshore infrastructure design.
How to cite: Leonardi, A., Pasqua, A., and Cabrera, M.: Submarine landslide modelling to evaluate hazard to offshore linear infrastructure, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11856, https://doi.org/10.5194/egusphere-egu25-11856, 2025.
Posters virtual: Mon, 28 Apr, 14:00–15:45 | vPoster spot 3
EGU25-21656 | Posters virtual | VPS12
Centrifuge modelling of a roto-translational landslide in stiff clay formationMon, 28 Apr, 14:00–15:45 (CEST) | vP3.1
Roto-translational landslides are characterized by two movement types at different landslide parts, i.e., rotational movement at the headscarp and translational movement at the toe. They are widely distributed in clay formations with planar or subhorizontal layers, posing threats to human life and infrastructure. Due to the different shapes of the sliding surfaces, the kinematics of roto-translational landslides show complicated patterns with varying spatial and temporal distributions. Forecasting the rapid sliding of roto-translational landslides presents challenges, as they often manifest as unnoticed slowly movement. The sliding surfaces of the roto-translational landslides feature concave-upward shape at the landslide head and a planar shape at the landslide accumulation zone, leading to complex deformation mechanisms. Roto-translational landslides usually exhibit creep deformation along sliding surfaces, showing transverse cracks on the ground surfaces. However, the scarcity of experimental data has significantly hindered a deep understanding of their failure mechanisms. Our research probes into the rotational failure phenomena of landslides in stiff clay formations, utilizing geotechnical centrifuge modelling and laboratory creep tests. Our findings reveal that rotational failures in model slopes are exclusively triggered under conditions of an undrained boundary at the basal shear zone. The post-failure behaviour is characterized by a settlement at the slope crest and a pronounced bulge at the toe, resulting in complex rotational movements along the basal sliding surface. Moreover, our laboratory experiments illuminate the creep behaviour of shear-zone materials under undrained conditions. In particular, samples with a high initial water content under sustained loading are highly susceptible to a quick transition into tertiary creep, leading to accelerated failure. These experimental insights substantially advance our understanding of the rotational failure patterns observed in clay-based landslides.
How to cite: Peng, X., Kang, X., and Wu, W.: Centrifuge modelling of a roto-translational landslide in stiff clay formation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21656, https://doi.org/10.5194/egusphere-egu25-21656, 2025.
EGU25-5029 | Posters virtual | VPS12
Geologic and morphologic characteristics of Nergeeti landslide, Imereti, GeorgiaMon, 28 Apr, 14:00–15:45 (CEST) | vP3.2
The fatal rock avalanche type landslide occurred in the northern part of the village Nergeeti (Imereti region) on February 7, 2024, which destroyed private houses, damaged a road, water supply, gas pipelines and different infrastructure objects, moreover, 9 persons lost their lives. The study area is located in the Khanistskali river valley and tectonically represents a frontal part of the Adjara-Trialeti fold-and-thrust Belt. Here, it is represented the data based on a detailed field investigation conducted to characterize the landslide body and identify its parameters (using a UAV). Slope is represented by the Middle Eocene (Zekari suite) volcanic and sedimentary rocks such as - tuffs, volcanic sandstones, volcanic breccias, and clays. These sediments are overlaid by the Quaternary diluvium-colluvium deposits. According to the local meteorological station, the total amount of precipitation during February 5-7 was 81 mm, which represents 46% of the entire month’s precipitation, generally. The AMSL of a main scarp and a base of the landslide body varies from 378 to 215 meters. Based on a DTM and field investigations, the total area of the landslide mass is 4.45 ha, while the height of a main scarp reaches up to 30 meters. The width in the upper part is 45-50 meters, while in the lower parts, it widens up to 140-160 meters. Moreover, nearby living 7 families were recommended to be moved to a low-risk area by the specialists of the Department of Geology of the National Environmental Agency. Event once again clearly shows the importance of integrating and advancing interdisciplinary methods in studying geohazards in a rapidly changing environment.
How to cite: Gaprindashvili, G., Gaprindashvili, M., Giorgadze, A., and Kurtsikidze, O.: Geologic and morphologic characteristics of Nergeeti landslide, Imereti, Georgia, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5029, https://doi.org/10.5194/egusphere-egu25-5029, 2025.
EGU25-16734 | ECS | Posters virtual | VPS12
Rockfall susceptibility and trajectory simulations for enhanced monitoring and early warning systems along roads: the Maratea landslide case studyMon, 28 Apr, 14:00–15:45 (CEST) | vP3.3
On the 30th of November 2022, a major rockfall event occurred in the Triassic dolostones of Castrocucco cliff (Maratea, Southern Italy), mobilising a volume of about 8000 m3 (Minervino Amodio et al. 2024) and destroying the underlying SS18 national road with no fatalities. The SS18 has critical importance in an area of high tourist, landscape, and historical interests, and determined the planning of a bypass tunnel to avoid the cliff, which has been affected by recurring instability events in the last decades (Pellicani et al. 2016). However, before the tunnel could be completed, the safe reopening of the road was critical for the region. For this reason, a high-resolution monitoring system was developed, enabling the timely road closure to the traffic in case of new failure (Santo and Massaro 2024).
In this study, we describe the geo-structural investigation and reconstruction of the rockfall kinematics and triggering factors, as well as the susceptibility analysis carried out to develop the monitoring system that allowed the road to reopen. Such a system consisted of a network of sensors placed in the areas and on the rock blocks that showed high levels of susceptibility to rockfalls. The data collection was performed through field and digital surveys. The latter was carried out on Virtual Outcrop Models (VOM) following drone photo acquisition. Successively, the rock block trajectories were simulated under static and seismically induced conditions with different block volume scenarios. These results, integrated with the real-time deformation data recorded by the sensors, will enhance the mitigation plan further. Moreover, the developed methodological approach and workflow could be applied to similar situations where critical road infrastructures lie in areas of high susceptibility to rockfall.
Minervino Amodio A, Corrado G, Gallo IG, Gioia D, Schiattarella M, Vitale V and Robustelli G (2024) Three-dimensional rockslide analysis using unmanned aerial vehicle and lidar: The Castrocucco case study, Southern Italy. Remote Sensing, 16 (12), 2235. doi: 10.3390/rs16122235
Pellicani R, Spilotro G and Van Westen CJ (2016) Rockfall trajectory modeling combined with heuristic analysis for assessing the rockfall hazard along the Maratea SS18 coastal road (Basilicata, Southern Italy). Landslides, 13: 985-1003. doi: 10.1007/s10346-015-0665-3
Santo A and Massaro L (2024) Landslide monitoring and maintenance plan along infrastructure: The example of the Maratea major rockfall (Southern Italy). Landslides. doi: 10.1007/s10346-024-02409-3
How to cite: Massaro, L., Falcone, G., Urciuoli, G., and Santo, A.: Rockfall susceptibility and trajectory simulations for enhanced monitoring and early warning systems along roads: the Maratea landslide case study, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16734, https://doi.org/10.5194/egusphere-egu25-16734, 2025.
EGU25-9926 | ECS | Posters virtual | VPS12
High-Resolution 3D MPM Simulation of the 2011 Akatani LandslideMon, 28 Apr, 14:00–15:45 (CEST) | vP3.4
The Akatani landslide, located on the Kii Peninsula of Japan, is a catastrophic deep-seated landslide triggered by intense rainfall during Typhoon Talas in 2011. The landslide mass travels a considerable distance, forming a landslide dam at the slope foot. Its instability is primarily attributed to the rapid reduction of shear strength in sandstone–mudstone (shale) materials and elevated pore water pressure. In this study, a fully three-dimensional physical model based on the Material Point Method (MPM) is applied for the first time to investigate the Akatani landslide. By employing the high-performance solver MaterialPointSolver.jl, an advanced numerical simulation is conducted, integrating geotechnical parameters from ring shear tests, pore pressure characteristics, and field-based geological and topographical data. The proposed model effectively replicates the rainfall-triggered reactivation of the landslide along pre-existing sliding surfaces identified through the Sloping Local Base Level (SLBL) [1, 2]. It captures the failure process, from initial instability to rapid downslope movement and channel blockage, under a coupled solid–fluid framework. Comparisons with field observations and previous LS-Rapid simulations demonstrate the high accuracy and applicability of this modeling approach. These findings provide essential insights for understanding the dynamic mechanisms of deep-seated rainfall-induced landslides, evaluating secondary disaster risks, and developing effective disaster mitigation strategies.
References
[1]. Chigira, M., Tsou, C. Y., Matsushi, Y., Hiraishi, N., & Matsuzawa, M. (2013). Topographic precursors and geological structures of deep-seated catastrophic landslides caused by Typhoon Talas. Geomorphology, 201, 479-493.
[2]. Jaboyedoff, M., Chigira, M., Arai, N., Derron, M. H., Rudaz, B., & Tsou, C. Y. (2019). Testing a failure surface prediction and deposit reconstruction method for a landslide cluster that occurred during Typhoon Talas (Japan). Earth Surface Dynamics, 7(2), 439-458.
How to cite: Huo, Z., Tang, X., Jaboyedoff, M., Podladchikov, Y., and Chigira, M.: High-Resolution 3D MPM Simulation of the 2011 Akatani Landslide, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9926, https://doi.org/10.5194/egusphere-egu25-9926, 2025.
EGU25-20680 | Posters virtual | VPS12
Landslide evaluation applying electrical tomography techniques: study case San José de Aloburo, Pimampiro,ImbaburaMon, 28 Apr, 14:00–15:45 (CEST) | vP3.5
Landslides affect millions of people annually in the mountainous regions of Latin America, resulting in significant economic, human and structural losses (Carrasco et al., 2011). The San José de Aloburo landslide, located in Imbabura-Ecuador, occurred in November 2021, significantly changing the landscape as well as the increase of the substantial damage to the locality. Vásquez et al. (2021) characterized it as a complex rotational landslide, highlighting its geomorphological and stratigraphical particularities. This study aims to integrate geophysical and geological approaches to further analyze the internal structure and physical properties of the materials involved in the landslide.
The methodology included the application of electrical resistivity tomography (ERT) profiles (Perrone, 2014), using low-cost equipment, suitable for the economic context of the region. It allowed to identify variations in the subsurface resistivity. Stratigraphic columns were constructed also to analyze the interlaying and composition of the displaced geological strata. In addition, a granulometric analysis was carried out on a representative sample to evaluate the particle size distribution.
The results reveal significant variations in resistivity associated with the distribution of the displaced materials and the presence of complex internal morphology. Likewise, the integration of geophysical and geological data allowed a more precise delineation of the rupture zone, the depth of displacement and the characteristics of the materials involved. These findings provide valuable information for understanding landslide processes in the region and monitoring this type of events with the additional advantage of being economically accessible.
Keywords: Landslides, Electrical Resistivity Tomography (ERT), Geophysical Integration
References:
Carrasco, J., et al. (2011). Impactos del cambio climático, adaptación y desarrollo en las regiones montañosas de América latina. Ministerio
de Relaciones Exteriores, Gobierno de Chile-Alianza para las Montañas-FAO-Banco Mundial.
Perrone, A., et al. (2014) Electrical resistivity tomography technique for landslide investigation: A review. Earth-Science Reviews, 135 , 65-82.
Vázquez, Y., et al. (2021). Informe técnico sobre el movimiento en masa ocurrido en san José de Aloburo (noviembre/2021), Pimampiro,
Imbabura. Escuela de Ciencias de la Tierra, Energía y Ambiente, Yachay Tech.
How to cite: Mayacela-Salazar, B., Torres-Ramirez, R., and Perez-Roa, R.: Landslide evaluation applying electrical tomography techniques: study case San José de Aloburo, Pimampiro,Imbabura, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20680, https://doi.org/10.5194/egusphere-egu25-20680, 2025.
EGU25-9062 | ECS | Posters virtual | VPS12
Runout Mechanism of Flow-like Landslides Based on Granular Flow PhysicsMon, 28 Apr, 14:00–15:45 (CEST) | vP3.6
Characterized by sudden occurrence, high velocity and long runout distance, flow-like landslides pose great threats to human communities. In essence, flow-like landslides can be regarded as the flow of granular materials under different topographic conditions, driven by external triggers or internal state changes. During the movement of landslides, the motion behavior transitions from a solid-like state to a fluid-like state, finally resulting in its extreme mobility. Based on the granular flow physics, we investigate the dynamic process of flow-like landslides from a rheological perspective, thereby exploring the motion transition from a solid-like state to a fluid-like state and its hypermobility feature. We utilize an elastic viscoplastic constitutive model to capture the changes in the motion behavior of landslides during their movement. This model accounts for both the elastic response of the material under low-strain conditions and the viscoplastic behavior under large strains, and incorporates both stress and strain rate dependencies, which help in describing the progressive transition from a solid-like deformation to a fluid- like flow. For practice, numerical analyses of column collapse are conducted using the Material Point Method (MPM), a numerical technique well-suited for simulating large deformations. Moreover, a typical flow-like landslide in China, the Luanshibao landslide, is well studied to investigate its long runout mechanism.
How to cite: Tang, X., He, S., Zhu, L., Zhang, H., Jaboyedoff, M., and Huo, Z.: Runout Mechanism of Flow-like Landslides Based on Granular Flow Physics, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9062, https://doi.org/10.5194/egusphere-egu25-9062, 2025.
EGU25-17719 | ECS | Posters virtual | VPS12
Quantifying pre-collapse dynamics of hanging rock-ice masses using remote sensing datasetsMon, 28 Apr, 14:00–15:45 (CEST) | vP3.27
Changing climate is enhancing the occurrence and intensity of natural disasters, profoundly impacting human lives, livelihoods, infrastructure, and economic growth. Modelling and prediction of deadly high-mountain slope failure hazards such as snow, ice, and rock avalanches have always been challenging. Current in-situ sensor-based approaches for slope failure predictions of hanging glaciers and rock faces are quite limited in their spatial continuity and extent and there is also a research gap on linking the pre-collapse slope movements with subsequent avalanche runouts. Earth observation datasets can offer a viable alternative for quantifying and monitoring pre-collapse dynamics at larger spatial scales. For the catastrophic 2021 rock-ice collapse in Chamoli, India, several studies had reported some anomalous movements weeks-to-months prior to the collapse. However, we need more analyses to understand how common such pre-collapse anomalous movements are before we can even start considering investigating them as potential precursors for effective avalanche predictions. To fill this research gap, using satellite remote sensing datasets and digital elevation models, we investigated several high-mountain slope failure events (e.g., Piz Scerscen in 2024, Piz Cengalo Bondo in 2017) of varying magnitudes and nature (i.e., rockfall, rock-ice avalanche, and ice avalanche) in different topographical and climate settings. While we were able to quantify pre-collapse dynamics for these events, we also observed variations in the occurrence and magnitude of anomalous movements prior to the events. These preliminary findings are encouraging and the future research and results from such analyses can bridge the knowledge gap on the detection and modelling capabilities, ultimately enhancing resilience to mountain hazards.
How to cite: Sam, L., Bhardwaj, A., and Temadri, P.: Quantifying pre-collapse dynamics of hanging rock-ice masses using remote sensing datasets, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17719, https://doi.org/10.5194/egusphere-egu25-17719, 2025.
