Landslides Essay

Introduction
Landslides are one of the most common destructive geological processes on the surface of the Earth and are accountable for loss of lives and property every year. Landslides are frequent and widespread geomorphological phenomena over mountainous regions and steep terrains are affected severely. It destroys fertile lands and is a major threat to urban and industrial development. Landslides cause changes in the morphology of the landscape and drop in land productivity (Blaschke et al., 2000).
Most of the mountainous regions over the globe have been hit adversely by landslides and experienced socio-economic losses (Sidle and Ochiai, 2006). The after effects of the landslides are severe in developing countries (including India), mountainous regions and remote areas (Himalayas) due to lack of financial resources and inadequate disaster management policies. Terrain instability and slope failures in mountain regions are one of the major concerns of land managers and policy makers worldwide.

Information on 'where' and 'when' the landslides may occur is the basic requirement of proper landslide assessment studies. Heavy rainfall is one of the triggering factors of landslides over mountainous terrains. Although the problem and the causes are quite evident, at present no system is available to model, regionally or globally, the threshold amount of rainfall to trigger landslides in different types of terrains. Better and more effective spatial coverage of landslide susceptibility mapping and hazard monitoring for vulnerable regions is an important task and need to be taken in priority (Sidle and Ochiai,