MAGNITUDE AND FREQUENCY OF ROCKFALLS IN THE LATE HOLOCENE - IMPLICATIONS FOR HAZARD AND RISK

The frequency and magnitude of rockfalls, rockslides and rock avlanches has been a major scientific interest since the beginning of the scientific observation of rock slope failure (Heim 1932). However, it is still unclear what factors control magnitude and frequency spectra of rock slope failure and to what degree they have change in the (Late) Holocene. Since different magnitudes pose very different types of hazards this is an important issue for the anticipation of potential risks.

We use a very detailed inventory covering 600 years rock slope failure in the Wetterstein Mountains (Zugspitze area) to analyse what kind of informations and approaches could help to answer this question. This can also be related to the varying hazard potential that has been effected by rockfalls in the past, the present and the future caused by varying frequencies of rainstorms and permafrost degradation.

Here we show, that there is certain sedimentary and process-related evidence that the magnitude-frequency spectra of rockfalls have considerably changed in the Late Holocene.