Source: HT
Context: A 4.4 magnitude earthquake with epicentre in Jhajjar (Haryana) shook Delhi-NCR recently, reviving concerns about the region’s high seismic vulnerability.
About Vulnerability of Delhi-NCR to Earthquakes:
- What is Delhi’s seismic risk?
- Delhi lies in Seismic Zone IV, classified as a high-damage risk zone by the Bureau of Indian Standards (BIS).
- The region is prone to moderate to strong earthquakes, with magnitudes reaching 5–6 occasionally and potential for 7+ magnitude events.
- How vulnerable is Delhi-NCR?
- Dense population, unregulated construction, and aging infrastructure make Delhi highly susceptible to earthquake-induced damage.
- The National Center for Seismology (NCS) has highlighted frequent tremors from shallow-focus quakes due to nearby active faults.
- Reasons Behind Earthquake Vulnerability:
- Proximity to Himalayan Frontal Thrust: Delhi is close to the tectonically active Himalayan belt, where the Indian and Eurasian plates collide, generating deep-seated stress.
- Active Fault Lines Across NCR: Major fault systems include the Delhi-Haridwar Ridge, Delhi-Moradabad Fault, Sohna Fault, and Mahendragarh-Dehradun Fault, increasing seismic risk.
- Subsurface Weak Zones: Seismic studies identify lineaments like the Yamuna and Ganga River faults, indicating deep crustal weaknesses.
- Historical Seismicity Pattern: Delhi has experienced at least five quakes of 5.5–6.7 magnitude since 1720, indicating recurring seismic events.
- Rapid Urbanisation Without Seismic Code Compliance: Unplanned growth and lack of enforcement of IS-1893 seismic design codes elevate structural vulnerability.
