Syllabus: GS I Geography – Earthquakes
“Why is the Himalayan region highly susceptible to earthquakes, and what measures can be taken to mitigate their impact?”
(15 marks, 250 words)
Introduction
The Himalayan region, part of the Alpine-Himalayan seismic belt, is one of the most earthquake-prone areas in the world due to its dynamic tectonic setting. This seismic vulnerability arises from the collision between the Indian and Eurasian plates, making it critical to understand the reasons for this activity and adopt effective mitigation strategies to reduce the devastating impacts of earthquakes.
Body
Reasons for High Earthquake Vulnerability in the Himalayan Region
- Tectonic Plate Collision
- The Indian plate subducts under the Eurasian plate at a rate of 4-5 cm/year, creating immense stress that periodically releases as earthquakes.
- Example: The 2015 Nepal earthquake (7.8 magnitude), which caused over 9,000 deaths and widespread destruction.
- Fault Lines and Thrust Zones
- Fault systems such as the Main Central Thrust (MCT), Main Boundary Thrust (MBT), and Main Frontal Thrust (MFT) are zones of stress accumulation.
- Example: The 1991 Uttarkashi earthquake (magnitude 6.8), associated with the MBT, caused significant loss of life and property.
- Seismic Gaps
- Unruptured sections of major fault lines, such as the Central Himalayan seismic gap, are potential sites for future large earthquakes.
- Example: Studies by NGRI highlight the heightened risk in regions like the Kashmir-Himachal and Kumaon-Garhwal sectors.
- Shallow Focus Earthquakes
- Most Himalayan earthquakes have a shallow focus (<20 km depth), causing severe surface-level damage.
- Example: The 1905 Kangra earthquake (magnitude 7.8) led to over 20,000 deaths.
- Fragile Geology
- The Himalayas, being young fold mountains, have unstable geological formations prone to landslides, rockfalls, and soil erosion, increasing vulnerability.
- Example: The 2013 Kedarnath disaster, exacerbated by unstable mountain geology.
Mitigation Measures
- Strict Implementation of Earthquake-Resistant Building Codes
- Enforce BIS standards for structures in seismic zones (Zone IV and V).
- Example: The 2016 National Building Code emphasizes earthquake-resistant designs, yet compliance remains weak in rural areas.
- Seismic Early Warning Systems
- Deploy advanced technologies like IoT, AI, and real-time seismic monitoring for early warnings.
- Example: Uttarakhand’s pilot early warning system has demonstrated success in issuing alerts for small tremors.
- Community Preparedness and Public Awareness
- Conduct regular drills, training, and capacity-building programs to foster disaster resilience.
- Example: NDMA’s “Earthquake Safety Week” campaigns, particularly in high-risk states like Himachal Pradesh and Uttarakhand.
- Land-Use Planning and Regulation
- Restrict construction in high-risk areas such as steep slopes, river valleys, and landslide-prone zones.
- Example: Nainital Master Plan (2023) regulates construction in identified hazard-prone areas.
- Retrofitting Critical Infrastructure
- Upgrade existing structures like schools, hospitals, and dams to comply with earthquake-resistant standards.
- Example: Retrofitting efforts at Tehri Dam in Uttarakhand to withstand seismic shocks.
- Strengthening Institutional and Technical Capacity
- Bolster institutions like NDMA, NIDM, and SDRF for effective disaster management.
- Enhance research in seismology to map seismic zones and predict earthquake behavior.
- International Cooperation
- Collaborate with global institutions like UNISDR and implement frameworks like the Sendai Framework for Disaster Risk Reduction.
Conclusion
The Himalayan region’s earthquake vulnerability necessitates a proactive and comprehensive approach that integrates scientific, technological, and community-driven strategies. Structural measures like robust building codes, early warning systems, and infrastructure retrofitting must work in tandem with non-structural measures such as public awareness and land-use planning. A holistic approach, coupled with strong governance and international cooperation, is essential to mitigate risks and enhance resilience in this seismically active region.
