Landslide Atlas of India

Topic: Natural Hazards and Disaster Management in India · NCERT: Beyond NCERT

Meaning

The Landslide Atlas of India is a set of maps released by the National Remote Sensing Centre (NRSC) of ISRO on 18 March 2023. It records about 80,000 landslides mapped between 1998 and 2022 and ranks 147 districts by how exposed they are to landslides [2].

It matters because it gives India one national record of where landslides have already happened. Planners can use this record to decide where to build roads, towns and dams, and where to send warnings.

Explanation

What the atlas is

• The atlas is a landslide inventory. An inventory is a list and map of landslides that have already happened, with their location and date.
• It is not a forecast. It shows the past, and that helps us judge the future.
• It covers 17 states and 2 UTs in the Himalaya and the Western Ghats [2].
• It ranks 147 districts by landslide exposure, which means how much a district is threatened by landslides [2].
• Rudraprayag (Uttarakhand) ranks as the most exposed district.

• Tehri Garhwal (Uttarakhand) comes second.

• It also ranks the districts of Himachal Pradesh by landslide risk exposure [1].

How it was made: remote sensing

• Remote sensing means studying the Earth from far away, usually from satellites, without touching the ground.
• How it works:
• Satellites take images of the same hill area before and after heavy rain or an earthquake.
• A fresh landslide shows up as a bare scar of rock and soil where there used to be forest or grass.

• Experts mark each scar on the map and add it to the inventory.

• Satellites used: IRS-1D, the Resourcesat and Cartosat series, Sentinel-1 and 2, Pleiades and WorldView [2].

• Resourcesat and Cartosat are Indian satellites. Cartosat takes very sharp images that are used to make maps.

• Why satellites help: landslides depend on local factors such as rock type, slope, rain and land use, and these change from one hillside to the next. Checking every slope on foot is slow and costly. Satellites can cover large, remote mountain areas quickly.

Three types of inventory in the atlas

Type	What it records	Example from the atlas
Seasonal	All landslides in one rainy season	Rainy seasons of 2014 and 2017 [2]
Event-based	Landslides caused by one big disaster	Kedarnath and Kerala [2]
Route-wise	Landslides along important travel routes	Tourist and pilgrim routes [2]

Why some areas show so many landslides

• Himalaya: young fold mountains that are still rising and tectonically active (the plates beneath them are still moving). The rocks are soft and break easily, and the slopes are steep. Monsoon rain, earthquakes and road and dam building add to the problem.
• Western Ghats: the rocks are hard and old, but the western face has steep cliffs and gets very heavy monsoon rain. Mechanical weathering (rock heats by day and cools by night, so it cracks) also weakens the rock.
• Result: the atlas shows the most landslides where weak or steep slopes meet heavy rain and human pressure.

Where it occurs

• Run by: the National Remote Sensing Centre (NRSC), ISRO. It was released on 18 March 2023 [2].
• Time period: landslides from 1998 to 2022 [2].
• Area covered: 17 states and 2 UTs across the Himalaya and the Western Ghats [2].
• Top districts:
• Rudraprayag, Uttarakhand (most exposed)

• Tehri Garhwal, Uttarakhand (second)

• Most affected states: Mizoram (north-east) and Uttarakhand (Himalaya).

• Event areas mapped: Kedarnath (Uttarakhand) and Kerala (Western Ghats) [2].
• Routes mapped: tourist and pilgrim routes in the hills [2].
• Wider picture: about 0.42 million sq km, or 12.6% of India's land area (not counting snow-covered areas), is landslide-prone (GSI) [1].

Don't confuse with

• National Landslide Susceptibility Mapping (NLSM): run by the Geological Survey of India (GSI), not ISRO. It maps susceptibility (how likely land is to slide in future) at 1:50,000 scale. It covers about 4.3 lakh sq km in 19 states/UTs and checked 33,904 landslides on the ground [3]. The Atlas is a satellite inventory of past landslides.
• National Landslide Forecasting Centre (NLFC): set up by GSI and inaugurated on 19 July 2024. It gives early warnings of rain-triggered landslides using rainfall thresholds and weather models [3]. The Atlas does not forecast.
• NCERT landslide vulnerability zones (Figure 6.9): these group India into very high, high, moderate to low and other zones using geology, slope, rain and earthquakes. The Atlas instead ranks districts using 80,000 mapped landslides [2].
• Joshimath land subsidence (2023): this happened in Chamoli district, and it is sinking ground, not a landslide. Do not mix Chamoli up with Rudraprayag, the Atlas's top district.

Prelims Hooks

• The Landslide Atlas of India was released by NRSC (ISRO) on 18 March 2023, not by GSI or NDMA [2].
• It maps about 80,000 landslides from 1998 to 2022 and ranks 147 districts in 17 states and 2 UTs [2].
• Most exposed district: Rudraprayag (Uttarakhand), followed by Tehri Garhwal. Mizoram and Uttarakhand are among the most affected states.
• It has three inventory types: seasonal (2014 and 2017 monsoons), event-based (Kedarnath, Kerala) and route-wise (tourist and pilgrim routes) [2].
• Satellites used: IRS-1D, Resourcesat, Cartosat, Sentinel-1 and 2, Pleiades and WorldView [2].
• Trap: GSI runs NLSM (1:50,000) and the NLFC (2024) [3]. ISRO's NRSC made the Atlas [2].

Mains Points

• Using geospatial data for disaster risk reduction (GS-III, Sendai Framework): India is moving from giving relief after a disaster to reducing risk before it. Each tool does a different job:
• Map the past: the NRSC Atlas inventory [2].
• Map the future risk: GSI's NLSM at 1:50,000 [3].
• Warn in time: the NLFC's rain-based forecasts [3].

• Answer frame: these should feed into district land-use plans and local evacuation plans.

• Development versus fragile hills (GS-I/GS-III): the top-ranked districts lie in the young Himalaya, where tectonics, steep slopes and monsoon rain combine. Roads, tunnels, dams and unplanned building add to this pressure.

• Answer frame: use the Atlas's district rankings and route-wise maps to limit roads, large dams and big settlements in high-risk zones, and to carry out carrying-capacity studies for hill towns.

• Protecting pilgrim and tourist routes (GS-III, infrastructure): route-wise inventories show where landslides keep blocking roads [2].

• Mitigation: slope drainage, retaining structures, afforestation (planting forests on a large scale) and bunds (low banks of earth or stone that slow water running down a slope) at known landslide spots.
• Why it matters: this cuts losses to trade and travel (spatial interaction) in hill areas.

Related concepts

• Landslide
• Landslide vulnerability zones
• Landslides in the Himalayas and Western Ghats
• Landslide mitigation
• Malpa landslide
• Land subsidence
• Joshimath land subsidence (2023)
• Wayanad landslides (2024)

Read more

• Landslides and land subsidence