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India’s first high-resolution landslide susceptibility map

GS Paper  1

 Syllabus: Geography/ Disaster Management


Source: TH

 Context: IIT Delhi’s HydroSense Lab has created India’s first high-resolution landslide susceptibility map.


What is Landslide Susceptibility Mapping?

Landslide Susceptibility Mapping involves creating maps that depict areas prone to landslides based on certain factors. For example, using data on past landslide events and factors like slope steepness, soil type, and vegetation cover, a computer model can analyse these variables to predict areas at high risk.


Features of National Landslide Susceptibility Map:

Data SourcesThe map incorporates 1.5 lakh known landslide events from sources like the Geological Survey of India (GSI). It also considers 16 landslide conditioning factors, including soil cover, tree density, proximity to roads or mountains, etc.
Machine Learning AnalysisEnsemble machine learning methods were employed to analyse the data. This involves using multiple machine learning models together to mitigate the impact of any single model’s limitations.
High-Resolution MappingThe map provides a high-resolution overview with a detailed resolution of 100 sqm., offering insights into landslide susceptibility across India.
Identification of New Risk ZonesFamiliar areas with high susceptibility, such as the Himalayan foothills, Assam-Meghalaya region, and Western Ghats, were identified.
New risk zones, previously unrecognized, were also revealed, including parts of the Eastern Ghats north of Andhra Pradesh and Odisha.
Online AccessibilityThe map is available online and accessible to the public. It allows anyone to interact with the data without requiring technical expertise.
Future UseThe map aims to assist policymakers and organizations in landslide investigation and mitigation, and the team plans to develop a Landslide Early Warning System for India


About Landslide:

A landslide is “a movement of a mass of rock, earth or debris down a slope”.


Types of flows

  1. Debris flows: It is a form of rapid mass movement in which a combination of loose soil, rock, organic matter, and slurry that flows downslope. They are commonly caused by intense precipitation or rapid snowmelt.
  2. Earth flow: It is a down-slope viscous flow of fine-grained material saturated with water.
  3. Mudflow:A mudflow is a wet or viscous fluid mass of fine and coarse-grained material that flows rapidly along drainage channels.
  4. Creep:Creep is the slow, steady, downward movement of material under gravity that occurs in a large area


India’s Vulnerability to Landslides (as per ISRO’s Landslide Atlas of India)

  1. Global Ranking: India ranks among the top five countries globally prone to landslides, witnessing at least one death per 100 sq km annually due to such events.
  2. Primary Cause: Rainfall variability, particularly in the Himalayas and Western Ghats, stands as the predominant cause of landslides in India.
  3. Geographical Vulnerability: Excluding snow-covered areas, over 12% of the country’s geographical land area is susceptible to landslides.
  4. Regional Breakdown:
    1. Over 66% of landslides occur in the North-western Himalayas.
      1. Rudraprayag and Tehri Garhwal districts of Uttarakhand have the highest landslide density and landslide risk exposure in the country.
    2. About 19% are reported in the North-eastern Himalayas.
    3. The Western Ghats contribute to over 14% of landslide events.
  5. Impact in the Western Ghats: Despite fewer occurrences, landslides in the Western Ghats pose significant risks, especially in Kerala, making inhabitants vulnerable to fatalities.


Causes of Landslides:

Causes of LandslidesDetails
Heavy RainfallExcessive rainfall saturates the soil, increasing its weight and reducing cohesion. This weakens slopes, particularly during heavy rain, making them more susceptible to landslides.
Steep SlopesAreas with steep terrain face greater landslide risk as gravitational forces act more intensely on sloping surfaces, especially during heavy rainfall or seismic activity.
EarthquakesSeismic activity can disrupt slope balance, triggering landslides. Volcanic eruptions, such as pyroclastic flows, displacing soil and rock, also contribute to landslide occurrences.
Human ActivitiesDeforestation, mining, construction, and excavation alter landscapes, remove vegetation, and disturb slope balance. These activities weaken terrain stability, escalating the risk of landslides.
Underlying GeologyThe type of rock and soil beneath an area influences landslide susceptibility. Loose, unconsolidated soil is more prone to landslides, while stable bedrock, typical in the Himalayan landscape, is less likely to experience such events.


Effects of landslides:

  • Loss of Life: According to the International Disaster Database (EM-DAT), landslides have caused over 50,000 fatalities worldwide between 2000 and 2020.
    • In the state of Uttarakhand, India, the 2013 Kedarnath disaster resulted in approximately 6000 deaths.
  • Environmental Impact: Soil erosion caused by landslides can lead to sedimentation in rivers and streams, affecting water quality and aquatic life.
    • The 2014 landslide in Oso, Washington, resulted in significant damage to the Stillaguamish River ecosystem.
  • Infrastructure Disruption: Landslides can block critical transportation routes.
    • In February 2021, the Chamoli disaster led to the blockage of the Rishi Ganga River and the destruction of various infrastructure in the region.
  • Property Damage: The cost of repairing or rebuilding homes, infrastructure, and farmlands can be substantial.
  • Displacement: The United Nations Office for Disaster Risk Reduction (UNDRR) reports that landslides triggered by heavy rainfall in Nepal in 2020 displaced more than 9,000 households, leaving many families without shelter.


Recent examples of landslide disasters in the past year:

  • Joshimath Sinking in Uttarakhand
  • June 2023: A landslide in the Noney district of Manipur, India, killed at least 58 people.
  • May 2023: A landslide in Rio de Janeiro, Brazil, killed at least 232 people.
  • March 2023: A landslide in Putumayo, Colombia, killed at least 323 people.


Government Measures for Landslide Impact Mitigation:

  • The National Landslide Susceptibility Mapping (NLSM) Programme (initiated by the Geological Survey of India in 2014) aims to
    1. Map the 0.42 million sq. km landslide-prone areas across India at a Macro Scale (1:50,000)
    2. Create a dynamic National Landslide Susceptibility Geodatabase for India
  • Establish a nationwide repository on GIS-based Landslide Inventory
  1. The goal is to enhance understanding, assessment, and management of landslide-prone regions in the country through comprehensive mapping and geospatial analysis.
  • National Remote Sensing Centre (NRSC) under the Indian Space Research Organisation (ISRO) has released the Landslide Atlas of India, a detailed guide identifying Landslide Hotspots in the country.


NDMA Guidelines:

National Disaster Management Guideline on Management of Landslides and Snow Avalanches

  1. Hazard, Vulnerability & Risk Assessment: Identify areas prone to landslide hazards and assess resources at risk
  2. Early Warning Systems: Continuous monitoring of movements, stress development, and timely data transmission
  3. Investigations for Risk Assessment: Multi-disciplinary investigations for comprehensive risk assessment leading to the formulation of standards to effectively mitigate the impact of landslides


Way Forward for Landslide Management in India:

Way ForwardDetails
Landslide MonitoringInvolves deploying sensors, satellite imagery, and ground-based instruments for detecting ground movement and potential landslide precursors.
NHAI’s Landslip Detection SystemThe National Highways Authority of India (NHAI) plans to install a landslip detection system on the Kochi-Dhanushkodi National Highway in Munnar. The system, developed by IIT-Mandi, the Indian Army, and DRDO, aims to provide early warnings about landslips.
Landslide Hazard MapsGeneration of reliable landslide hazard maps using advanced tools like UAVs, Terrestrial Laser Scanners, and high-resolution Earth Observation (EO) data.
International Best PracticesLearning from Brazil’s SNAKE System, a Landslide Early Warning System (LEWS), to incorporate digital monitoring, forecasting, and alert mechanisms.
Special Purpose Vehicle (SPV) for Landslide ManagementFormation of an expert professional group at the national level to study and decide on risk mitigation strategies to recommend permanent fixes for identified landslide hotspots.
Awareness ProgrammesInitiatives aimed at creating a culture of awareness, alertness and preparedness among the public.
Monitoring Construction and DevelopmentImplementing strict monitoring of construction and developmental activities, such as roads and dams, in landslide-prone areas.
Limiting Agriculture and SettlementsRestricting agriculture to valleys and areas with moderate slopes, controlling large settlements in high vulnerability zones.
Afforestation and Water Flow ControlPromoting large-scale afforestation programs and constructing bunds to reduce water flow.
Encouraging Terrace FarmingEncouraging terrace farming, especially in northeastern hill states where Jhumming (Slash and Burn/Shifting Cultivation) is prevalent.



Understanding the causes and effects of landslides is essential for disaster preparedness and mitigation efforts. Implementing early warning systems, land-use planning, and sustainable land management practices can help reduce the vulnerability of communities to landslide hazards. Moreover, international cooperation and sharing of knowledge and best practices are crucial in addressing the challenges posed.


Insta Links:

Landslide Atlas of India


Mains Link:

Disaster preparedness is the first step in any disaster management process. Explain how hazard zonation mapping will help disaster mitigation in the case of landslides UPSC 2019

Differentiate the causes of landslides in the Himalayan region and Western Ghats (UPSC 2021)