Abstract

On the regional scale, landslide, a slope process, often occurs in monsoon in the high mountains in the tropical and high precipitation climatic zone. The occurrence of landslides was frequently assigned to the decisive role of intense or prolonged rainfall. However, on the local scale and in small geographic areas, where the same vegetation, duration and intensity of rain exist, rain often triggers landslides on only specific slopes and rocks. Apart from that, landslides can re-occur at the same location afterwards. The complicated and almost irregular nature of landslides requires a deep understanding of the endogenous and exogenous geological factors that can generate or play a significant role in the landslide process in a given area from which it is possible to delineate areas with a high risk of landslides. This research used the spatial statistical analysis of the relationship of 7855 historical landslides with tectonic factors, geological structures, litho-petrographic characteristics, and topographic slope. Our results indicated that fault zones and petrographic features are the most critical factors controlling the formation of landslides. Most landslides occur on the slope of 5 to 20 degrees. The areas where fault zones cut through magmatic and metamorphic rocks are likely to be more favourable for generating landslides of considerable size and volumes than the areas where the fault zones cut through the terrigenous rocks.