Context: Landslide susceptibility mapping of Mussoorie and its surrounding areas in Uttarakhand Himalaya, Study show that 15 percent of the region is highly susceptible to landslides.
Background

• Like most hill townships, Mussoorie, a popular hill station in Uttarakhand, has witnessed several landslides, probably resulting from an increased spate of developmental activities.
• The increased disaster hazard has led scientists to map the landslide susceptibility of Mussoorie and surrounding areas, showing that 15 percent of the region is highly susceptible to landslides.

Key findings of the Study

• Scientists from Wadia Institute of Himalayan Geology (WIHG), an autonomous institute under the Department of Science and Technology, Govt. of India, carried out the study in Mussoorie township and its surroundings covering 84 square km in the Lesser Himalaya.
• They found that a dominant part of the area falls under very high and high landslide susceptible zone lies in the settlement area – Bhataghat, George Everest, Kempty fall, Khattapani, Library road, Galogidhar, and Hathipaon.
• The area is also covered by highly fractured Krol limestone exhibiting a slope of more than 60 degrees.
• As per the study, the various causative factors of landslides in the area are lithology, land use-landcover (LULC), slope, aspect, curvature, elevation, road-cut drainage, and lineament.

About National Landslide Susceptibility Mapping

• Geological Survey of India has launched and undertook a national programme on landslide susceptibility mapping – Macro scale (1:50,000) National Landslide Susceptibility Mapping (NLSM) with an aim to cover the 0.42 million sq. km landslide prone areas of the country.
• This national programme was formally launched in 2014.
• The mapping divides landslide-prone areas into three categories – high, moderate and low.

Aims and Objectives

• To create a dynamic National Landslide Susceptibility Geo database for India
• To prepare GIS – based seamless Landslide Susceptibility Maps of India on 1:50,000 scale
• To prepare a nation-wide repository on GIS-based Landslide Inventory

What is a landslide?

• Landslide is a physical phenomenon when a part of rock, and/or debris/ soil fall due to the action of gravity.
• It is caused by a set of terrain-specific geofactors (e.g., slope, lithology, rock structure, land use/ cover, geomorphology etc.).