LANDSLIDE HAZARD ASSESMENT AND SUSCEPTIBILITY MAPPING: A CASE STUDY OF THE MARCH 2020 CHOZOLI LANDSLIDE IN RUMPHI DISTRICT

Chozoli in the south of Rumphi experienced a landslide recently on 6th march 2020. Rumphi is a mountainous area characterized by a great number of hill and the area experience frequent high landslide occurrences causing a lot of damage to farmlands, non-cultivated lands, people’s properties, and sometimes loss of lives. In this study five factors including surface texture of the soil, type of geology, Landcover/ land use, rainfall and slope gradient were used to identify which was the most contributing factor of the 2020 Chozoli landslide. GIS-based Statistical information value method was used in the preparation of the landslide susceptibility map where factors such as Land cover, slope gradient of the terrain, soil type and geology were used as the input data. The effect of these landslide causing factors was determined in relation to slope instability. Google earth imagery was used to determine the distance covered by a landslide and its depth. Chozoli landslide susceptibility map was categorized into five classes which included very low, low, moderate, high, and very high. The results from susceptibility mapping showed that high and very high landslide susceptibility areas fell under hilly areas with high slope gradient and mostly bare and agricultural lands. Landslide susceptibility mapping is of high importance since it can be used for regional land use planning and landslide hazard mitigation purposes. Keywords: landslide, geographic information systems (GIS), susceptibility, land cover, information value, Rockfall, rotational, translational, geohazard, Debris flow.

Rumphi is a mountainous area characterized by a great number of hill and the area experience frequent high landslide occurrences causing a lot of damage to farmlands, non-cultivated lands, people’s properties, and sometimes loss of lives. In this study five factors including surface texture of the soil, type of geology, Landcover/ land use, rainfall and slope gradient were used to identify which was the most contributing factor of the 2020 Chozoli landslide. GIS-based Statistical information value method was used in the preparation of the landslide susceptibility map where factors such as Land cover, slope gradient of the terrain, soil type and geology were used as the input data. The results from susceptibility mapping showed that high and very high landslide susceptibility areas fell under hilly areas with high slope gradient and mostly bare and agricultural lands.

Chozoli is locates in the southern part of Rumphi district. The area covers about 350.940Km2
and it is located 6.87 km away from Bolero and 8.59 km away from Rumphi central. The area lies within Nyika area which extends from just south of Karonga (near the northern end of Lake Malawi) to just north of Rumphi and lies on the geographical coordinates between 33046’40’’E, 10057’30’’S and 33046’40’’E, 11000’’17’’S.
The area is mainly drained by Runyina River which is in the western part and further west of it is Luviri which forms the main tributary.

Traditional authority: TA Chikulamayembe

District: Rumphi

Coordinates: -10.9657, 33.75375