Earthquakes, Seismic Zonation & Landslides
The Indian subcontinent exhibits high seismic vulnerability resulting from the ongoing northward collision of the Indian tectonic plate into the Eurasian plate at a rate of approximately 4 to 5 centimetres per year. The Bureau of Indian Standards (BIS IS 1893:2016) classifies India into four seismic hazard zones: Zone II (Low), Zone III (Moderate), Zone IV (High), and Zone V (Very High), with the Himalayan arc, Northeast India, and the Rann of Kutch placed in Zone V. Seismic mitigation mandates earthquake-resistant construction conforming to national building codes, retrofitting critical infrastructure, and real-time seismic monitoring by the National Centre for Seismology. Additionally, hilly terrains in the Himalayas and Western Ghats face severe landslide hazards, mitigated through Geological Survey of India landslide zonation mapping.
Key Concepts & Examination Highlights
- India is divided into four seismic zones by BIS: Zone II (least active) to Zone V (most active/highest risk); Zone I was merged into Zone II.
- Zone V encompasses the entire North-Eastern region, parts of Jammu & Kashmir, Himachal Pradesh, Uttarakhand, Rann of Kutch, and Andaman & Nicobar Islands.
- The National Centre for Seismology (NCS) under the Ministry of Earth Sciences maintains the National Seismological Network.
- Geological Survey of India (GSI) launched the National Landslide Susceptibility Mapping (NLSM) program covering 0.42 million sq km.