Factors affecting Landslides in the Matara district

Abstract

Landslides pose a serious threat to landslides are caused by a number of geophysical and human factors in mountain areas with steep slopes. This paper presents an analysis of some of the factors affecting landslides in the Matara district. Considering the high degree of vulnerability, Pasgoda and Kotapola Divisional Secretariat Divisions have been chosen as the field setting for this particular study. Landslides which are distributed among two selected Divisional Secretariat Divisions have been studied adopting observation method. An observation checklist has been applied in order to collect data on geology, geomorphology, lithology, thickness of debris layer and its composition, degree of slope drinange system, type of natural vegetation, landuse and other human activities. Monthly rainfall data have been analyzed to identify the relationship between the occurrence of landslides and rainfall intensity. The observations and analysis reveal that combination of a number of factors is responsible for the vulnerability of landslides in Matara District. Slopes which measured 16-30 degree are liable to trigger off in many areas. A significant relationship between intensity of rainfall and occurrence of landslides is observed in the area. Also, human activities such as slope cutting and unsuitable landuse practices attribute to trigger off many slopes in Matara district.