Landslide Atlas of India
26-08-2023
12:04 PM
1 min read
What’s in today’s article?
- Why in News?
- What is a Landslide and what Causes one?
- How are Landslides Classified and Mapped?
- How Prone is India to Landslides?
- Landslide Atlas of India
- What does the Landslide Atlas Suggest?
Why in News?
- The Central government formally outlined the Digital India Act, 2023.
What is a Landslide and what Causes one?
- A landslide is defined as the movement of a mass of rock, debris, or earth down a slope.
- Landslides are a type of "mass wasting," which denotes any down-slope movement of soil and rock under the direct influence of gravity.
- Landslides occur mainly in mountainous terrains where there are conducive conditions of soil, rock, geology and slope.
- Natural Causes that trigger it include heavy rainfall, earthquakes, snow melting and undercutting of slopes due to flooding.
- Landslides can also be caused by Anthropogenic Activities such as excavation, cutting of hills and trees, excessive infrastructure development, and overgrazing by cattle.
- In India, rainfall-induced landslide events are more common.
How are Landslides Classified and Mapped?
- Landslides are broadly classified based on the –
Image Caption: Types of Landslides
How Prone is India to Landslides?
- India is considered among the top five landslide-prone countries in the world.
- In India, at least one death per 100 sq. km is reported in a year due to a landslide event.
- Rainfall variability pattern is the single biggest cause for landslides in the country, with the Himalayas and the Western Ghats remaining highly vulnerable.
- Excluding snow covered areas, 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 per cent 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.
Landslide Atlas of India
- The Landslide Atlas of India is prepared by the National Remote Sensing Centre (NRSC).
- NRSC is one of the primary centres of Indian Space Research Organisation (ISRO), Department of Space (DOS).
- NRSC has created a pan-India database of ~80,000 landslides those occurred during last two decades using satellite data.
- This database contains both seasonal landslides and event-based landslides.
- It is a rich collection of landslide inventory which will help user departments in prioritisation of developmental activities in tectonically and ecologically sensitive mountainous areas in India.
What does the Landslide Atlas Suggest?
Image Caption: India’s vulnerability to landslides
- 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.
- Likewise, 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.
- Among all these states, an alarming situation is emerging from Uttarakhand and Kerala.
- Uttarakhand –
- Uttarakhand’s fragility was recently exposed during the land subsidence events reported from Joshimath since January.
- The state has experienced the second highest number (11,219) of landslides since 1998.
- Kerala –
- Kerala has been consistently reporting massive landslides since it suffered the century’s worst floods in 2018.
- The year-wise landslide events here are 2018 (5,191), 2019 (756), 2020 (9) and 2021 (29).
- Uttarakhand –
- Most Vulnerable District?
- From the events and images obtained, the NRSC ranked Rudraprayag in Uttarakhand at the top of 147 vulnerable districts.
- It has the highest landslide density in the country, along with having the highest exposure to total population and number of houses.
Q1) What causes landslides?
Landslides are caused by disturbances in the natural stability of a slope. They can accompany heavy rains or follow droughts, earthquakes, or volcanic eruptions.
Q2) What is the difference between endogenic & exogenic forces?
Endogenic forces produce after-effects that are visible only after it causes sudden damage. Exogenic forces create changes visible over a period of thousands or millions of years.
Source: Landslide Atlas of India: Which states, regions are most vulnerable