Bergstürze - Begriff, Ursachen und Einflussfaktoren, Prozessausl?sung, H?ufigkeit， Prozesskette und Umgang mit Bergsturzproblematik (Beitrag AGN)

摘要

In the first section, the term rock avalanche [Bergsturz] is explained, and its use in Switzerland for events with volumes over 1 million m3 which should generally be determined by the initial landslide volume. In the second section, the causes and influencing factors of rock avalanches are discussed. The emphasis is placed on the description of geological and morphological disposition. Tectonic preconditioning and the influence of gravity on the weakening of the rock mass are key elements of the disposition. These factors cause a continuous or step-wise Long-duration weakening of the rock mass in the initiation zone, especially through various weathering processes, until the rock mass is 《ripe》 for failure. The initiation of the rock ava- Lanche, or trigger, is generally caused by water in the rock mass, or less often by earthquakes. It is not clear to which extent the thawing of permafrost ice can directly trigger such Large processes. It therefore remains unclear how the frequency of Large events such as rock avalanches will increase as global warming continues. Basically, rock avalanches are very rare, with one to two events per decade occurring in Switzerland.