Evaluation of earthquake-induced landslides hazard zonation methods: a case study of Sarein, Iran, earthquake (1997)

Abstract

Landslides, in general, and seismic landslides, specifically, are among the phenomena that caused a huge loss to the humans over the past years. In this research, one of the novel methods for seismic landslides hazard zonation, a comprehensive areal model of earthquake-induced landslides (CAMEL), is applied to predict the concentration and hazard induced by the landslides and evaluate these landslides by the quantitative approaches. In this regard, the zone affected by the M w = 6.1 Sarein earthquake (1997) was selected as the model area. At first, the necessary information including disturbance distance (distance from river and road), ground strength class, ground moisture, shaking intensity, slope angle, slope height, soil depth, terrain roughness, material type, and vegetation were collected using aerial photos, Landsat satellite images, geological and topographic maps, and site investigation of the studied region. These data were digitized and weighed using the digital geographic information system (GIS) in a comparative manner, and then concentration and hazard of the seismic landslides were predicted using the CAMEL program. Next, by empirical comparing the landslides triggered by Sarein earthquake and the predicted concentration, the accuracy of this technique was evaluated. It can be inferred that CAMEL predicts soil landslides concentration more efficient than rock landslides. For rock slumps and block slides, CAMEL’s performance was slightly poorer. The model predicted a low occurrence of rock slumps and block slides, when none in fact occurred. A similar comparison with the Sarein case study was also conducted using a quantitative method. The accuracy of both quantitative and CAMEL approaches was evaluated using the quantitative zonation, revealing improved performance with CAMEL.