Risk of Earthquakes in India: Overview

Risk of Earthquakes in India: Overview

Question: Scientists, geophysicists and seismologists of around 27 nations are working under Indian leadership on ambitious project to develop early warning system of earthquakes. Discuss the factors that influence the risk of earthquakes in India.

- The rapidly expanding population of India as well as non scientific constructions, huge factory buildings and malls, supermarkets and warehouses place India at a huge risk

- Over the past 15 years, India has experienced 10 major earthquakes which have resulted in 20,000 deaths

- Current seismic zone map of the country holds that more than 59% of the land area of this nation is under moderate to severe threat of an earthquake and prone to shaking of MSK Intensity 7 and above, according to BMTPC

- The most recent strong earthquake to strike Asia was the Nepal quake whereby aftershocks are still being felt in the region.

- At one time, regions of the country located at a distance from the Himalayas and inter-plate boundaries were safe from damage caused by earthquakes; in recent times, these areas have also received quakes though of a lower magnitude

- Areas surrounding Koyna were redesigned to Seismic Zone IV suggesting high hazard following a quake in this region in the year 1967

- Killari earthquake in 1993 caused low hazar zone of Seismic Zone 1 to be merged with 2. In certain parts of Deccan and Peninsular India, regions were brought under Seismic zone III comprising areas considered moderate hazard zone.

- As the comprehension of the risks of quakes in this region improves, so will the areas designated as highly hazardous or vice versa

- NE part of the nation experiences moderate to large earthquakes at frequent intervals

- On an average, NE region experiences an earthquake with magnitude higher than 6.0 on the Richter Scale each year

- Andaman and Nicobar Islands are also located on inter-plate boundary and experience damaging quakes

Factors Causing Increased Risk

Factors leading to increased risk of earthquakes include the following

- Spurt in developmental activities

- Uncontrolled urbanisation

- Unbalanced economic development

- Limitless globalisation of the Indian economy

- Increase in use of high-tech tools and equipments in service and manufacturing industries

Facts and Stats

- Entire Himalayan belt is prone to earthquakes higher than 8.0 in magnitude

- In a relatively short span of around 5 decades, 4 major earthquakes have occurred in the region namely:

- Shillong earthquake at 8.7 on the Richter Scale in 1897

- Kangra earthquake at M8 in 1905

- M8.3 earthquake in Bihar-Nepal in 1934

- Assam Tibet earthquake of M8.6 in 1950

- Scientists are currently working on a model which seeks to analyse changes caused by chemical and physical displacements as a predictor of earthquakes

- India is going to launch a satellite by the year 2019 which will transmit messages of surface displacement up to precision of few cm

- 22 states in India are prone to earthquakes of varying intensities such as severe, moderate, high and low

- During the past 10 years, 11 earthquakes of M5 or more on the Richter scale have impacted India