Knowledge based landslide susceptibility mapping in the Himalayas

Abstract

Background: Landslides are common geological hazard occurring in the mountainous region. The Himalayan belt is prone to landslide disasters, which is directly linked to the prosperity and development of the area. The present study was carried out around the Chamoli-Joshimath area, which is situated in the Northernmost-belt of the Garhwal Himalaya, India. A strategic road connecting Tibet which also links the famous Hindu temples Badrinath and Kedarnath traverses the area. The main purposes of the present study is to delineate the landslide susceptible zones in the area so that it could be helpful towards landslide disaster risk reduction and to highlight the applicability of knowledge based susceptibility mapping method in the Himalayas. Results: The area comprises low-to-high grade metamorphic rocks as well as carbonate rocks such as limestone and dolomite. In the study area, most of the landslides occur along the road and river sections, and in the thrust or fault zones. The landslide zones are strongly controlled by the Main Central Thrust and other faults and the resulting geomorphic condition. Most of the unstable slopes are prone to plane and wedge failures. There are many active and dormant landslides (covered by vegetation) in the area. The active landslides are due to reactivation of pre-existing ones. Conclusions: The predicted landslide susceptible zones are in good agreement with the historical landslide locations, which is good indication that knowledge based landslide susceptibility mapping can be successfully applied in the Himalayas provided the causative factors are thoroughly understood.