Earthquake-induced hazards in mountain regions: a review of case histories from Central Asia – an inaugural lecture to the society.

This paper presents a summary of the main trigger factors of earthquake-induced landslides as well as a review of case histories of major landslide-triggering earthquake events in Central Asia. The goal is to analyse the relationship between geological, tectonic and morphological conditions and the susceptibility to seismic slope failure and to show the potential long-term contribution of seismic ground motion dynamics, such as site effects and liquefaction, to slope failure.
Case histories related to five M>7 earthquake events in the Tien Shan and Pamir Mountains are outlined: the earthquakes of Kemin in 1911, Sarez in 1911, Khait in 1949, Gissar in 1989 and Suusamyr in 1992. The Kainama earth-flow case history of 2005 is added to document possible mid-term effects of smaller earthquakes. These events show that in the Central Asian Mountains, two types of seismically triggered mass movements may have particularly disastrous effects: massive long rockslides and medium-sized earth flows made of loess – or a mixture of both. Actually, the most catastrophic mass movement of the last century in Central Asia triggered by the 1949 Khait earthquake was a massive long runout rock avalanche, which had gained a very high velocity due to the entrainment of loess sediments and related lubrification.