1. Impact of an 0.2 km3 Rock Avalanche on Lake Eibsee (Bavarian Alps, Germany) – Part II: Catchment Response to Consecutive Debris Avalanche and Debris Flow
- Author
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Michael Krautblatter, Bernhard Lempe, Sibylle Knapp, Flavio S. Anselmetti, Anselmetti, Flavio S., 2 Institute of Geological Sciences and Oeschger Centre for Climate Change Research University of Bern Bern Switzerland, Lempe, Bernhard, 3 Engineering Geology Technical University of Munich Munich Germany, Krautblatter, Michael, and 1 Landslides Research Group Technical University of Munich Munich Germany
- Subjects
010504 meteorology & atmospheric sciences ,Geography, Planning and Development ,Drainage basin ,lake sediments ,010502 geochemistry & geophysics ,progressive slope failure ,01 natural sciences ,catchment response ,Debris flow ,law.invention ,lake impact ,law ,550 Earth sciences & geology ,Earth and Planetary Sciences (miscellaneous) ,Fernpass rockslide cluster ,Radiocarbon dating ,Sedimentology ,0105 earth and related environmental sciences ,Earth-Surface Processes ,geography ,geography.geographical_feature_category ,Landslide ,rock avalanche ,Rockslide ,prehistoric earthquake ,Debris ,ddc ,Erosion ,Physical geography ,recurrence rates ,Geology - Abstract
The ~0.2 km3 Eibsee rock avalanche impacted Paleolake Eibsee and completely displaced its waters. This study analyses the lake impact and the consequences, and the catchment response to the landslide. A quasi‐3D seismic reflection survey, four sediment cores from modern Lake Eibsee, reaching far down into the rock avalanche mass, nine radiocarbon ages, and geomorphic analysis allow us to distinguish the main rock avalanche event from a secondary debris avalanche and debris flow. The highly fluidized debris avalanche formed a megaturbidite and multiple swashes that are recorded in the lake sediments. The new calibrated age for the Eibsee rock avalanche of ~4080–3970 cal yr BP indicates a coincidence with rockslides in the Fernpass cluster and subaquatic landslides in Lake Piburg and Lake Plansee, and raises the possibility that a large regional earthquake triggered these events. We document a complex history of erosion and sedimentation in Lake Eibsee, and demonstrate how the catchment response and rebirth of the lake are revealed through the complementary application of geophysics, sedimentology, radiocarbon dating, and geomorphology. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd, Sedimentological, geophysical and geomorphological investigation in and around Lake Eibsee allows to decipher three rock‐slope failures from Mount Zugspitze: (i) the Eibsee rock avalanche ~4000 cal yr BP; (ii) a debris avalanche in the aftermath; and (iii) a large debris flow ~3740 cal yr BP. The Eibsee rock avalanche was re‐dated to a refined age of 4089–3876 cal yr BP. The coincidence with major events in the Fernpass rockslide cluster increases the likelihood of a prehistoric earthquake trigger., Studienstiftung des Deutschen Volkes e.V. (German National Academic Foundation): http://dx.doi.org/10.13039/501100004350, British Society for Geomorphology http://dx.doi.org/10.13039/100010165
- Published
- 2020