Use of Indirect Evidence for the Prehistoric Earthquake-Induced Landslides Identification

Abstract

Presence of large and/or long runout prehistoric rockslides is often equalized with an evidence of strong past earthquakes without providing any additional reasons in favor of such assumption—just due to enormous size and surface expression of these features. The erroneous assumption on seismic origin of a particular landslide or group of landslides would cause not only an overestimation of seismic hazard, but, also, underestimation of an overall landslide hazard due to much longer recurrence period of large earthquakes in comparison with other triggering phenomena like rainstorms. Examples of reliable substantiation of seismic origin of large rockslides based on identification of spatially distributed sedimentary features in the lacustrine environment closely timed to river damming event are presented and discussed.