GEOTEST (Switzerland)

The unstable rock slope "Spitze Stei" (Kandersteg, Switzerland) has shown significantly increased activity for several years. Since 2018, observed displacement rates can exceed 40 cm per day seasonally. The instability covers a total area of ​​approximately half a square km. The volume of the moving rock and debris mass is ~16 million m3, distributed across several rock compartments. Driven by degrading permafrost and enhanced gliding planes, these primary gravitational instabilities result in secondary, often destructive, debris flows into the Oeschibach channel. While continuous monitoring is essential for risk management, traditional visual and radar methods are often constrained by adverse weather conditions, limited temporal resolution and limited sensitivity to subsurface processes. To overcome these limitations and monitor rockslide internal deformation, material damage, and ongoing mass-movement processes at high spatial resolution, a dense temporary seismic network consisting of 64 SmartSolo nodes (natural frequency 5 Hz) were deployed across the slope at the end of June 2025 and operated for nearly three months. This dataset is complemented by recordings from three semi-permanent seismometers that have been operating since October 2021, providing a longer-term reference for background seismicity and site-specific noise characteristics.We analyze the continuous seismic records to detect and characterize signals from a variety of mass-movement phenomena, including rockfalls, granular flows, debris flows and avalanche-related activity. Signals are evaluated based on waveform properties, duration, amplitude evolution, and spectral content, with comparisons across sensor types and periods. A key objective is to isolate and cluster internal microseismic activity, distinguishing it from background noise, external sources (e.g., icequakes), and transient permafrost-related signals.Our preliminary results highlight a diverse set of seismic signal types linked to both surface processes and internal rockslide dynamics. This observed variability suggests changes in deformation style across different rock compartments, demonstrating the potential of dense nodal seismic arrays to resolve internal rockslide processes relevant for hazard monitoring.

<strong class="journal-contentHeaderColor">Abstract.</strong> We estimate the sub-surface energy budget and heat fluxes in the coarse-blocky active layer (AL) of the Murt&egrave;l rock glacier, a seasonally snow-covered permafrost landform located in the eastern Swiss Alps. In the highly permeable AL, conductive/diffusive heat transfer including thermal radiation, non-conductive heat transfer by air circulation (convection), and heat storage changes from seasonal accretion and melting of ground ice shape the ground thermal regime. We quantify individual heat fluxes based on a novel in-situ sensor array in the AL and direct observations of the ground ice melt in the years 2020&ndash;2022. Two thaw-season mechanisms render Murt&egrave;l rock glacier comparatively climate-resilient. First, the AL intercepts ~70 % (55&ndash;85 MJ m^&minus;2) of the thaw-season ground heat flux by melting ground ice that runs off as meltwater, ~20 % (10&ndash;20 MJ m^&minus;²) is spent on heating the blocks, and only ~10 % (7&ndash;13 MJ m^&minus;²) is transferred into the permafrost body beneath and causes slow permafrost degradation. Second, the effective thermal conductivity in the ventilated AL increases from 1.2&nbsp;W m^&minus;¹ K^&minus;¹ under strongly stable temperature gradients to episodically over 10&nbsp;W m^&minus;¹ K^&minus;¹ under unstable temperature gradients, favouring convective cooling by buoyancy-driven Rayleigh ventilation (thermal semiconductor effect). In winter, radiatively cooled air infiltrating through a discontinuous, semi-closed snowcover leads to strong AL cooling. The two characteristic parameters (effective thermal conductivity and intrinsic permeability) are sensitive to debris texture, hence these convective undercooling processes are specific to highly permeable coarse-blocky material.

Hydrogeological properties of fluid reservoirs in the brittle continental crust at 5 km have been deduced from hydraulic and chemical data provided by the Deep Heat Mining well Basel-1 in the south of the Upper Rhine rift valley (central Europe, Switzerland). The investigation was challenging because no direct temperature logs or fluid samples from the undisturbed reservoir exist. However, the properties of the undisturbed reservoir have been reliably reconstructed from short time hydraulic tests and the evolution of outflow water composition. The rock of the open hole sections (4629–5000 m) is predominantly coarse-grained undeformed poorly fractured quartz-monzodiorite. The permeability k = 5.8 × 10–18 m2 is characteristic for plutonic basement at 5 km depth. Fluid flow is restricted to few steeply dipping fracture zones in this section. Outflow water triggered by massive injection of river water contains predominantly NaCl. The total of dissolved solids (TDS) in the pristine reservoir at depth is about 45 g kg−1. The origin of the high salinity is probably fossil seawater. The water has been modified in the reservoir by desiccation reactions related to the partial and local hydration of the igneous reservoir rock. The estimated reservoir temperature of 185 °C using three different calibrations of standard fluid geothermometers is in excellent agreement with measured and extrapolated temperatures in the borehole. The consistent application of different fluid geothermometers confirms the rock control of the fluid composition.

On 27 December 2011, a rock avalanche in the upper Val Bondasca in the southern Swiss Alps deposited 1.5–1.7 million m3 of rock debris. The following summer, debris flow activity in Val Bondasca was unusually high with four events after a 90‐year period of debris flow inactivity. This was an exceptional situation for the valley. Analysing the 2012 events, the long‐term record of meteorological conditions such as rainfall intensity and duration, in comparison with debris flow activity, suggests that the meteorological conditions in summer 2012 would not have triggered the high intensity debris flow events without additional sediment input. Consequently, the suddenly increased debris availability can be considered a major factor in these events. Interestingly, rainfall events of similar magnitude in the subsequent years 2013–2015 did not trigger additional debris flow events, indicating that debris flow initiation thresholds are increasing again, back towards pre‐rock avalanche levels. This study aims to help in understanding the so far poorly understood temporal evolution of debris flow triggering thresholds and the effect of sudden changes in sediment availability.

In this paper, we describe the investigations and actions taken to reduce risk and prevent casualties from a catastrophic 210,000 m3 rockslope failure, which occurred near the village of Preonzo in the Swiss Alps on May 15, 2012. We describe the geological predisposition and displacement history before and during the accelerated creep stage as well as the development and operation of an efficient early warning system. The failure of May 15, 2012, occurred from a large and retrogressive instability in gneisses and amphibolites with a total volume of about 350,000 m3, which formed an alpine meadow 1250 m above the valley floor. About 140,000 m3 of unstable rock mass remained in place and might collapse partially or completely in the future. The instability showed clearly visible signs of movements along a tension crack since 1989 and accelerated creep with significant hydromechanical forcing since about 2006. Because the active rockslide at Preonzo threatened a large industrial facility and important transport routes located directly at the toe of the slope, an early warning system was installed in 2010. The thresholds for prealarm, general public alarm, and evacuation were derived from crack meter and total station monitoring data covering a period of about 10 years, supplemented with information from past failure events with similar predisposition. These thresholds were successfully applied to evacuate the industrial facility and to close important roads a few days before the catastrophic slope failure of May 15, 2012. The rock slope failure occurred in two events, exposing a compound rupture plane dipping 42° and generating deposits in the midslope portion with a travel angle of 39°. Three hours after the second rockslide, the fresh deposits became reactivated in a devastating debris avalanche that reached the foot of the slope but did not destroy any infrastructure. The final run-out distance of this combined rock collapse–debris avalanche corresponded to the predictions made in the year 2004.

Abstract. Damage caused by weather- and climate-related disasters have increased over the past decades, and growing exposure and wealth have been identified as main drivers of this increase. Disaster databases are a primary tool for the analysis of disaster characteristics and trends at global or national scales, and they support disaster risk reduction and climate change adaptation. However, the quality, consistency and completeness of different disaster databases are highly variable. Even though such variation critically influences the outcome of any study, comparative analyses of different databases are still rare to date. Furthermore, there is an unequal geographic distribution of current disaster trend studies, with developing countries being underrepresented. Here, we analyze three different disaster databases in the developing-country context of Peru: a global database (Emergency Events Database: EM-DAT), a multinational Latin American database (DesInventar) and a national database (Peruvian National Information System for the Prevention of Disasters: SINPAD). The analysis is performed across three dimensions: (1) spatial scales, from local to regional (provincial) and national scale; (2) timescales, from single events to decadal trends; and (3) disaster categories and metrics, including the number of single disaster event occurrence, or people killed and affected. Results show limited changes in disaster occurrence in the Cusco and ApurÍmac regions in southern Peru over the past four decades but strong positive trends in people affected at the national scale. We furthermore found large variations of the disaster metrics studied over different spatial and temporal scales, depending on the disaster database analyzed. We conclude and recommend that the type, method and source of documentation should be carefully evaluated for any analysis of disaster databases; reporting criteria should be improved and documentation efforts strengthened.

Based on glacier retreat and degrading permafrost in high alpine regions across the Bernese Oberland (Central Switzerland), several new hazardous source areas for processes became evident within the last years. The evaluation of susceptible periglacial areas and the assignment of resulting processes by modelling will be one of the major tasks to be solved in near future. The prediction of those processes and their consequences is an interdisciplinary question. Meteorological scenarios for the next 50 years derived from climate change scenarios stand at the beginning of the decision chain. Based on those, susceptible periglacial areas which act as starting zones for massmovements (rockfall, landslides, debris flows) or new sediment sources can be calculated through sophisticated permafrost and glacier retreat models. A vast basic monitoring of the permafrost by BTS measurements helps understanding on-going processes and is fundamental for the bedload calculation in the periglacial area, which is measured by monitoring systems at representative and characteristic locations within the study area (e.g. Spreitgraben near Guttannen, Switzerland). Dealing with large investigation areas of several 100 km2 it is important to use adequate models. Well established simulation tools have been used within the project. The result is a so called periglacial hazard indication map visualizing endangered areas in the year of 2060 for massmovement processes as well as other natural hazards like floods, glacial ice avalanche or subglacial lake outburst.

In urbanen Orten des alpinen Raums gewinnt die Nutzung der Geothermie aus mehreren hundert Metern Tiefe zunehmend an Bedeutung. Dabei stehen vor allem offene Systeme im Vordergrund. Die vorliegende Arbeit prasentiert die ersten Erkenntnisse zur Prospektion und Charakterisierung des bisher unerforschten, nutzbaren und ergiebigen Aquifers der Aroser Dolomiten. Neben der Anwendung von etablierten Methoden und Verfahren, wie seismischen Messungen, einer Erkundungsbohrung, bohrlochgeophysikalischen Messungen und Pumpversuchen, wird auch die Anwendung des KARSYS-Ansatzes zur geologischen und konzeptuellen hydrogeologischen 3D-Modellierung des Aquifers aufgezeigt. Zudem wird die Entwicklung eines Viewers zur 3D-Visualisierung von Bohrungen dokumentiert. Das methodische Vorgehen, bestehend aus hydrogeologischen und messtechnischen Ansatzen auf regionaler und lokaler Ebene, ermoglicht eine lithologische Faziesdifferenzierung der Aroser Dolomiten sowie eine Differenzierung der geklufteten und verkarsteten Bereiche innerhalb des Aquifers. Die Ergebnisse bilden die Grundlage fur eine weitergehende, auf Fundigkeit optimierende und Risiken minimierende Explorations- und Bohrplanung sowie fur eine nachhaltige Nutzungsplanung.

Abstract Numerical modelling of rockfall events is an increasingly significant basis for the production of hazard maps and the design of protection structures. The fact that the various programs on the market lead to different results in specific cases has led to discussion. The programs most commonly used in Switzerland are therefore compared with regard to input parameters and results, the main and auxiliary algorithms and further aspects. The difference between deterministic and probabilistic methods is important. The probabilistic method requires great caution and experience, both in the parameter input and in the interpretation of the results. This poses the general question, what uncertainties have to be dealt with in the management of natural hazards.Numerische Modellierungen von Steinschlagereignissen stellen eine zunehmend bedeutendere Grundlage für die Erstellung von Gefahrenkarten und die Bemessung von Schutzbauten dar. Dass die verschiedenen marktüblichen Programme bei konkreten Fragestellungen zu unterschiedlichen Resultaten führen, hat zu Diskussionen geführt. Die in der Schweiz am häufigsten eingesetzten Programme werden deshalb betreffend der Eingabeparameter und Resultate, der zugrunde liegenden Haupt‐ und Zusatzalgorithmen und weiterer Aspekte verglichen. Wichtig ist die Unterscheidung zwischen deterministischem und probabilistischem Ansatz. Der probabilistische Ansatz bedarf sowohl bei der Parametereingabe als auch bei der Interpretation der Resultate größter Sorgfalt und Erfahrung. Dabei stellt sich auch die generelle Frage, wie mit Unsicherheiten im Naturgefahrenmanagement umzugehen ist.