Landslide hazard zonation mapping on meso-scale in SH-37 ghat section, Nadugani, Gudalur, the Nilgiris, India

Abstract

Landslide is the most common natural disaster in mountainous regions. It causes damages to life and properties. The study area, Calicut–Nilampur–Gudalurghat section (SH37) falls under the Survey of India toposheet 58A-7/NE (1:25,000). The present study was carried out with landslide hazard zonation mapping on meso-scale. This paper explains how meso-zonation of landslide hazards (facet-wise) was made from investigations as per the norms given in Bureau of Indian Standard IS 14496:1998. Remote sensing and geographic information system (GIS) was utilized for the preparation of thematic maps on 1:10,000 scale. The present study evaluates more detailed related factors of inherent causative factors (lithology, structure, slope gradient, relative relief, land use/land cover, and hydrogeology) involved in landslides. This method also incorporates effects of external causative factors like seismicity and rainfall as corrected rating. In the study area, 10 different facets have been identified. This area falling in facets 3, 4, 6, 7, and 10 come under high hazardous zone, the slopes falling in the facets 1 and 5 fall in the moderate hazardous zone, facet 2 in low hazard zone and other facets 8 and 9 show very high hazardous zone. Details of this work are presented in this paper. The landslide inventory points were collected with the help GPS in this ghat section. The inventory percentage 3.3% comes in low hazard zone, 18% present in moderate hazard zone, 57.4% in high hazard zone, and 21.3% under very high hazard zone.