Журнал экологических опасностей

Landslides Mapping and Susceptibility Analysis Using RS and QGIS Techniques in Chiweta Area, Northern Malawi

Abstract

Dyson N Moses

Landslides are disastrous and fatal geohazard capable of retarding developmental process of the nation as it grapples with recovering from the damage incurred. In this study, Remote sensing (RS) and QGIS techniques were used to map out landslides and assess susceptibility to landslides occurrence around Chiweta area in Rumphi, Malawi. RS input data was acquired from a USGS website. Deskwork involved identification of sites of landslides occurrence on the downloaded satellite images. Fieldwork was then done to validate the information from satellite images. During the landslides mapping survey, 46 landslides were recorded. DEM data and landslides data were processed in QGIS to obtain the results. The outcome show that the distribution of mapped landslides and the exposure to landslides hazard risk is high on NE-SE and S-SW facing and occurred within 15 m distance to the road and 0-100 m from the major streams. Landslides also tend to concentrate in altitudes of 500-1000 and a few others in the 1000-1500 at slope angles ≥ 600 and in a rare phenomenon at ≤ 300. With respect to geology, mapped landslides are concentrated in sedimentary rocks which are inherently weak rocks as compared to crystalline rocks but some landslides were found in highly weathered cut metamorphic rocks.