Landslide Atlas of India

In News

• ISRO recently released the Landslide Atlas of India identifying landslide hotspots in the country.

About 

• ISRO’s National Remote Sensing Centre created a database of landslide-prone regions of India based on events during 1998 – 2022.
• In addition to aerial images, high-resolution satellite images captured using ResourceSat-1 and 2, etc., were used to study the landslides.
• The pan-India database classifies landslides into – seasonal (2014, and 2017 monsoon seasons), event-based and route-based (2000 – 2017).

What are Landslides?

• A landslide is defined as the movement of a mass of rock, debris, or earth down a slope.
• They are a type of mass wasting, which denotes any downward movement of soil and rock under the direct influence of gravity. They generally occur in clay-rich soil.
• In India the entire Himalayan tract, hills/mountains in sub-Himalayan terrains of North-east India, Western Ghats, the Nilgiris in Tamil Nadu and Konkan areas are landslide-prone.

India’s Vulnerability:

• India is among the top five landslide-prone countries globally, where at least one death per 100 sq km is reported in a year due to a landslide event.
• Excluding snow-covered areas, the Atlas states that 
  •  approximately 12.6 per cent of the country’s geographical land area (0.42 million sq km) is prone to landslides. 
  • As many as 66.5 percent of the landslides are reported from the North-western Himalayas, about 18.8 per cent from the North-eastern Himalayas, and about 14.7 per cent from the Western Ghats.
  • Rainfall variability pattern is the single biggest cause of landslides in the country, with the Himalayas and the Western Ghats remaining highly vulnerable.

Region-wise Distribution:

• Nearly half of the country’s landslide-prone area (0.18 sq km) is located in the states of Assam, Arunachal Pradesh, Sikkim, Meghalaya, Mizoram, Manipur, Tripura and Nagaland.
• Uttarakhand, Himachal Pradesh, Jammu and Kashmir cover 0.14 million sq km of the total landslide-prone areas.
• Maharashtra, Goa, Karnataka, Kerala, and Tamil Nadu account for 0.09 million sq km.
• The Araku region in Andhra Pradesh along the Eastern Ghats too has reported landslide events.

State-wise Distribution:

• Uttarakhand, Kerala, Jammu and Kashmir, Mizoram, Tripura, Nagaland and Arunachal Pradesh reported the highest number of landslides during 1998 – 2022.
• Mizoram topped the list, recording 12,385 landslide events in the past 25 years, of which 8,926 were recorded in 2017 alone. 
• 2,071 events of the total 2,132 landslides reported in Nagaland during this period occurred during the 2017 monsoon season. 
• Manipur, too, showed a similar trend, wherein 4,559 out of 5,494 landslide events were experienced during the rainy season of 2017. 

• Of the total 690, Tamil Nadu suffered 603 landslide events in 2018 alone.
•  The Himalayan state of Uttarakhand has experienced the second-highest number (11,219) of landslides since 1998, all events occurring post-2000.
• Despite fewer events in the Western Ghats, landslides were found to be making inhabitants significantly vulnerable to fatalities, especially in Kerala.

Government Initiatives to deal with landslides

• National Landslide Risk Management Strategy (2019): 
  • It covers all aspects of landslide disaster risk reduction and management, such as hazard mapping, monitoring, and early warning systems.
  • It includes awareness campaigns, capacity building, training, regulations, and policies, as well as landslide stabilisation and mitigation.
• National Disaster Management Authority (NDMA) Guidelines on Landslide Hazard Management (2009):
  • It outlines the steps that should be taken to reduce the risk of landslides.
  • It also identifies regions that are prone to landslides
  • Encourages the use of effective landslide rehabilitation and mitigation techniques.
• National Institute of Disaster Management (NIDM):
  • It was set up to provide capacity building and support to various national and state-level authorities in the area of disaster management and disaster risk reduction 

Source: IE