Quantification of meteorological conditions for rockfall triggers in Germany
Open Access
- 23 June 2022
- journal article
- research article
- Published by Copernicus GmbH in Natural Hazards and Earth System Sciences
- Vol. 22 (6), 2117-2130
- https://doi.org/10.5194/nhess-22-2117-2022
Abstract
A rockfall dataset for Germany is analysed with the objective of identifying the meteorological and hydrological (pre-)conditions that change the probability for such events in central Europe. The factors investigated in the analysis are precipitation amount and intensity, freeze–thaw cycles, and subsurface moisture. As there is no suitable observational dataset for all relevant subsurface moisture types (e.g. water in rock pores and cleft water) available, simulated soil moisture and a proxy for pore water are tested as substitutes. The potential triggering factors were analysed both for the day of the event and for the days leading up to it. A logistic regression model was built, which considers individual potential triggering factors and their interactions. It is found that the most important factor influencing rockfall probability in the research area is the precipitation amount at the day of the event, but the water content of the ground on that day and freeze–thaw cycles in the days prior to the event also influence the hazard probability. Comparing simulated soil moisture and the pore-water proxy as predictors for rockfall reveals that the proxy, calculated as accumulated precipitation minus potential evaporation, performs slightly better in the statistical model. Using the statistical model, the effects of meteorological conditions on rockfall probability in German low mountain ranges can be quantified. The model suggests that precipitation is most efficient when the pore-water content of the ground is high. An increase in daily precipitation from its local 50th percentile to its 90th percentile approximately doubles the probability for a rockfall event under median pore-water conditions. When the pore-water proxy is at its 95th percentile, the same increase in precipitation leads to a 4-fold increase in rockfall probability. The occurrence of a freeze–thaw cycle in the preceding days increases the rockfall hazard by about 50 %. The most critical combination can therefore be expected in winter and at the beginning of spring after a freeze–thaw transition, which is followed by a day with high precipitation amounts and takes place in a region preconditioned by a high level of subsurface moisture.Keywords
Funding Information
- Bundesministerium für Bildung und Forschung (01LP1903A, 01LP1903K, 01LP1903E)
This publication has 44 references indexed in Scilit:
- In situ rockfall testing in New South Wales, AustraliaInternational Journal of Rock Mechanics and Mining Sciences, 2012
- Deciphering the effect of climate change on landslide activity: A reviewGeomorphology, 2010
- Relevance of tectonic and structural parameters in Triassic bedrock formations to landslide susceptibility in Quaternary hillslope sedimentsQuaternary International, 2010
- Multiscale parameter regionalization of a grid‐based hydrologic model at the mesoscaleWater Resources Research, 2010
- A Multiscalar Drought Index Sensitive to Global Warming: The Standardized Precipitation Evapotranspiration IndexJournal of Climate, 2010
- Scoring Rules for Forecast VerificationMonthly Weather Review, 2010
- State of the art in rockfall – forest interactionsSchweizerische Zeitschrift fur Forstwesen, 2007
- Landslide susceptibility assessment using “weights-of-evidence” applied to a study area at the Jurassic escarpment (SW-Germany)Geomorphology, 2007
- The assessment of rockfall hazard at the base of talus slopesCanadian Geotechnical Journal, 1993
- A new look at the statistical model identificationIEEE Transactions on Automatic Control, 1974