Types of Slope Movement and Their Relation to Geology, Geological Structures and Topography in Central Nepal

Abstract

Types of slope movement are discussed in consideration of geology, geological structure with enphasis on rock types and rock structure and morphological development of the Lesser Himalaya in the central Nepal.In the Rosi Khola watershed which consists of schist, quarzite and granitic gneiss the surrounding zone of MCT (Main Central Thrust) is susceptible to rock fall due to cracks formation in the overturned fold. Largescale landslides are also distributed in this area, where depositional river terraces of natural dam origin were formed possibly by these landslides. Toppling has been formed in the steep homocline structure of Schist . Apart from these slumps are often observed on the gently sloping terrain with thick soil which has been protected from erosion.In the low-grade metamorphized rocks of Tamakoshi and Sunkoshi watersheds block slides, debris slide on the gentle slopes and rock fall on the steep slopes are frequently observed along the schistosity or joint planes. Cuesta topography widely distributed in these areas is considered to have been formed by these slope movement processes.Various types of slope movement proceed in relation to plane structure of rocks, fracturing along MCT zone and morphological development.