Amiya Landslide in the Catchment of Gaula River, Southern Kumaun, Uttaranchal

The southern hills of Kumaun in [he proximity of the Main Boundary Thrust (MBT) are prone to recurrent landslides. The slope failures are related to steeper angle of hillslope, extent and type of vegetation. structural condition of bedrock, and neotectonism of the MBT. This paper presents the case history of the Amiya landslide of I I July 1999, which has claimed 22 lives. including 2 persons in a place 20 km northeast of Kathgodarn in Kumaun. The slope failure was related to structural conditions of bedrock, particularly five sets of joint spacing and the proximity to the MBT, which has been affected by neotectonic movements In the recent past. The large number of structures a discontinuities have diminishethde stability of the Siwalik hill slopes, reducing the safety factor to 0.412. The landslip vector has a close parallel ism with the geometrically determined wedge failures responsible for the landslide.