Volcanism and Landslides
What the topic is and why it matters for UPSC
Volcanism and landslides are two of the most dynamic geological processes shaping the Indian sub‑continent. While volcanoes are the surface expression of mantle magmatism, landslides are gravity‑driven mass movements that often follow intense rainfall, seismic shaking or volcanic activity. Both phenomena have direct implications for human safety, infrastructure, water resources, agriculture, biodiversity and climate.
For a civil‑service aspirant, understanding these hazards is essential because:
- Disaster management & policy – The Ministry of Home Affairs (MHA) and the National Disaster Management Authority (NDMA) formulate mitigation strategies, early‑warning systems and relief measures based on scientific assessments of volcanic and landslide risk.
- Development planning – Large‑scale projects (highways, dams, mining, urban expansion) must incorporate geo‑technical studies to avoid triggering landslides or to respect volcanic exclusion zones.
- International obligations – India is a signatory to the UN Sendai Framework for Disaster Risk Reduction (2015‑2030) and the Paris Agreement, both of which require robust hazard mapping and climate‑adaptation measures.
Constitutional / Legal foundation
The State’s duty to protect life and property under Article 21 of the Constitution, coupled with the Disaster Management Act, 2005, provides the legal basis for preventive and remedial actions against volcanic eruptions and landslides.
Sub‑topics covered in this chapter
- Fundamentals of Volcanism
- Types of volcanoes (shield, stratovolcano, cinder cone)
- Magma genesis, plate‑tectonic settings, and Indian volcanic provinces (e.g., Deccan Traps, Barren Island, Narcondam)
- Volcanic Hazards
- Lava flows, pyroclastic density currents, ash fall, volcanic gases, lahars
- Monitoring techniques (seismology, gas emission, satellite remote sensing)
- Landslide Mechanics
- Classification (rock fall, debris flow, earth slide, slump, creep)
- Triggering factors: rainfall intensity, seismicity, anthropogenic activities, volcanic deposits
- Landslide Hazard Mapping & Zonation
- GIS‑based susceptibility models, remote‑sensing indices (e.g., NDVI, slope, curvature)
- Role of the Geological Survey of India (GSI) and State Disaster Management Authorities (SDMAs)
- Case Studies from India
- 1991 Barren Island eruption, 2001 Bhuj earthquake‑induced landslides, 2013 Kedarnath flash flood‑landslide, 2021 Uttarakhand debris flow, 2022 Kinnaur landslide
- Mitigation & Management Strategies
- Structural measures (retaining walls, diversion channels, early‑warning sirens)
- Non‑structural measures (land‑use zoning, community awareness, insurance schemes)
- Linkages with Climate Change
- Intensified monsoon variability, glacial melt‑induced slope instability, potential impact on dormant volcanic systems
Exam relevance
| Examination | Relevance | Typical Question Types |
|---|---|---|
| Pre‑lims | Direct factual recall and map‑based questions (e.g., location of active volcanoes, landslide‑prone districts). | MCQs, map‑pinning, statement‑assertion. |
| Mains | Analytical and policy‑oriented answers on disaster risk reduction, inter‑agency coordination, and sustainable development. | Essay, GS‑III (Disaster Management), GS‑II (Geography), optional papers (Geography, Environment, Public Administration). |
Mastering this chapter equips you to answer both objective and descriptive components, linking geophysical science with governance, policy formulation and sustainable development—core competencies for any UPSC aspirant.
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