GS3 PYQ 2021 (Mains Answer Writing): Earthquakes | UPSC Mains: Internal Security & Disaster Management PDF Download

Discuss about the vulnerability of India to earthquake related hazards. Give examples including the salient features of major disasters caused by earthquakes in different parts of India during the last three decades.  (UPSC GS3 2021)

Earthquake is sudden shaking of earth surface, while earthquake hazard is anything associated with an earthquake that can affect people’s day-to-day life. Earthquake hazards can range across ground shaking, surface rupture, landslide, liquefaction, tectonic deformation, tsunami etc.

Vulnerability of India to Earthquake-related hazards:

• According to BIS, more than 58.6 percent of the landmass is prone to earthquakes of moderate to very high intensity. The occurrence of the Killari earthquake in 1993 resulted in revision of the seismic zoning in India with the low hazard zone or Seismic Zone I being merged with Seismic Zone II. 
• Densely populated areas, extensive unscientific constructions and unplanned urbanization have increased risks associated with earthquake hazards. 
• Andaman & Nicobar Islands frequently experience damaging earthquakes due to being situated on an inter-plate boundary. 
• Increasing use of high-technology equipment, susceptible to small vibrations, in industry and academia, or underground utilities for electricity, internet etc. have increased susceptibility to disruption from relatively moderate ground shaking 
• Regions in Himalayan foothills are vulnerable to liquefaction and landslides due to earthquakes.  

Salient features of major disasters caused by earthquakes over last 3 decades:

• 1993 Latur: 6.2 magnitude; relatively shallow depth caused large surface damage; causes remain debatable due to lack of plate boundaries in the region. 
• 1999 Chamoli: Caused by thrust fault; resulted in landslides, changes in surface water flow, surface rupture and disconnected valleys. 
• 2001 Bhuj: Associated with a reactivated fault, which was previously unknown; Great loss of life and property due to unmindful construction. 
• 2004 Indian Ocean Tsunami: Created by under-water seismic activity, created massive waves which flooded coastal areas and Islands, causing long-term changes. 
• 2005 Kahmir: 7.6 magnitude; Caused by severe upthrust of Indian plate against Eurasian plate, it created multiple after-shocks. Infrastructure and communication were disrupted.

India’s vulnerability to various earthquake hazards requires astute handling and long-term planning. The reconstruction at Bhuj after the 2001 earthquake is an instructive example.