Location and likely size of the Eibsee and Ehrwald rock avalanches

Location and likely size of the Eibsee and Ehrwald rock avalanches

Candidate: Felix Hofmayer
Supervisors: Kerry Leith, Michael Krautblatter
Institution: Technical University of Munich
Activity: Completed summer 2015

Especially in alpine areas with a high density of population there is a huge risk of heavy rockfalls. Most of all in case there is a touristic dependency for the region. The Zugspitze with Garmisch-Patenkirchen at the bottom is a perfect example in addition with a ridge out of strongly fissured limestone. At the moment it is hard to predict if and why these big mass movements happen. To recognize this risk and so to reduce the danger it is essential to understand the processes in these mountains. It is the aim to unravel the reasons of the Eibsee Bergsturz and give proof with a numeric model. In order of this motivation a model was made with stress development and glacial cycles of the zugspitz region. At the beginning a reconstruction of glacial stands and their mass movement on and around the Zugspitze during the last glacial episodes got to be made. In order to analyze the rock behavior leading to the Eibseebergsturz it is necessary to calculate and visualize the volume of this event. Two profiles and numeric evaluations got to be done to answer the important question of stress development in this part of crust with brittle behavior. Therefor this work has to give the answer for the Ice loading and the rockfall volume, as well as for the reasons of the Bergsturz. Generally stress is induced through glacial loading and unloading which leads to a critical stressed crust and failure because of fracture development. In case a few boundaries are respected there will be a Bergsturz in the model. Most important are exceeded fracture limits, therefor the fact of the real Eibseebergsturz is evidence enough.

Final model stages for a 165 Mm3 rock avalanche

Final model stages for a 165 Mm3 rock avalanche