The Geological Survey of India is undertaking a ‘National Landslide Susceptibility Mapping’ in 18 states, including West Bengal, spanning approximately 4.27 lakh sq km of land and forest areas. The GSI had formulated a six-year perspective plan in 2014, keeping in view the rising frequency of landslides and slope failures in the mountainous regions, a statement issued by the Kolkata-based organisation said. The project is being executed in two phases, it said. The first phase has mapped Priority-1 areas with significant human settlements and roads, covering around 2.82 lakh sqkm. The second stage focused on Priority-2 areas in high altitudes with sparse or minimal settlements, spanning 1.45 lakh sqkm, the statement explained.
While Uttarakhand, Jammu & Kashmir, Himachal Pradesh and Sikkim have areas which fall both in Priority-1 and 2 zones, 13 states have places that come only under Priority-1 category. In West Bengal, both Darjeeling and Kalimpong districts have areas that fall under Priority-1. Arunachal Pradesh is the only state under Priority-2 category. The mapping divides landslide-prone areas into three categories – high, moderate and low. The information detailing area-wise particulars, past incidents, their magnitude and responsible factors is then fed into a GIS-based National Landslide Inventory along with satellite images and geological maps.
While maps covering about 70,000 sqkm area have already been uploaded in the “BHUKOSH” section of the GSI Portal(www.gsi.gov.in) for public use, information about another 1.71 lakh sqkm will be added to it by the end of 2018, the statement said. Nearly 15 per cent of Indian landmass is covered by hilly terrains where landslides or slope failures of varying types and magnitudes are reported every year, it added.