Recent Earthquake-Triggered Landslide Events in Central Asia, Evidence of Seismic Landslides in the Lesser Caucasus and the Carpathians

Abstract

AbstractThis chapter presents an overview of earthquake-triggered landslide hazards in Central Asia, with a focus on the Tien Shan and Pamir Mountain Ranges. It essentially compiles information presented by the author in his previous publications as well as other published results. This overview will show that in Central Asian mountain areas, most giant mass movements are likely to have a seismic origin—though it cannot be proved for most of them (see companion report by A. Strom). Here, we will briefly introduce those paleo-cases to establish a link with the Carpathian Mountains and the Lesser Caucasus, where old massive landslides could have a seismic origin as well and thus could provide information on ancient high-magnitude earthquakes for which no written information is available. In recent history, large earthquakes triggered only minor slope failures in the Carpathians and the Lesser Caucasus, while almost all M > 7 events that occurred last century in Central Asian mountain ranges triggered numerous landslides, including at least one two-billion m3 mass movement. However, none of these events can be compared with the 1999 Chi-Chi, the 2005 Kashmir or the 2008 Wenchuan earthquakes, which had triggered many thousands of landslides. The question is then—are such events impossible in Central Asia (maybe due to the much dryer climate than in the regions affected by the cited earthquakes) even though high-magnitude earthquakes are relatively common in the Tien Shan and Pamir? One possible response will be provided by a detailed outline of the largest earthquake disaster that had affected the Central Asian mountain regions in historic times: the Khait event in 1949. Some additional notes will outline the potential for future massive landslide activation during earthquakes in Armenia and Romania.