Earthquake in Lucknow: Which are the most earthquake-vulnerable regions in India?

An earthquake with a magnitude of 5.2 on the Richter scale rocked Uttar Pradesh's capital Lucknow on Saturday morning. National Center for Seismology informed that the earthquake hit the city at 1.12 am at a depth of 82 kilometers. "Earthquake of magnitude:5.2 occurred on 20-08-2022, 01:12:47 IST, Lat: 28.07 and Long: 81.25, Depth: 82 Km, Location: 139 km NNE of Lucknow, Uttar Pradesh," tweeted the National Center for Seismology," it said in a tweet.

What's an earthquake?

The outer surface of the Earth has large, thin, rigid plates called the tectonic plates. They move very slowly but sometimes they get stuck at their edges due to friction. When the edge overcomes friction, there is a release of a massive wave of energy that travels through the crust of the earth. This is called an earthquake. The places where the edges get stuck are called faults.

Earthquake occurs dozens of kilometers below the surface. When they occur under the land mass, the massive amount of energy shakes the ground destroying infrastructure. When they occur below the surface of the ocean, they trigger tsunamis. An earthquake above 6 on the Richter scale is potentially devastating.

Earthquakes in India

India has witnessed several catastrophic earthquakes in its long history. Thousands of people died in the Bhuj earthquake in 2001. The country receives hundreds of mild earthquakes every year. According to some studies, 54 percent of the land in India is vulnerable to earthquakes. India is divided into four seismic zones - Zone 2, 3, 4 and 5. Zone 5 is most vulnerable to earthquakes, Zone 2 is the least.

Zone 5 is considered to be the Ver High Damage Risk Zone. Kashmir, Western and Central Himalayas, North and Middle Bihar, North-east, and the Andaman and Nicobar islands comprise this zone. Its zone factor is 0,36. Structural designers take this factor into account when designing earthquake-resistant buildings. 

Zone 4 is the High Damage Risk Zone. The zone factor here is 0.24. Jammu and Kashmir, Delhi, Ladakh, Uttarakhand, Himachal Pradesh, Punjab, Chandigarh, West UP, Bihar, and north Bengal fall into this Zoe.  

Zone 3: Cities like Chennai, Mumbai, Kolkata and Bhubaneshwar fall into this zone. This is a Moderate Damage Risk Zone with a zone factor of 0.16. 

Zone 2: Cities like Bulandshahr, Moradabad, and Gorakhpur fall into this zone. This zone has very low chances of an earthquake and it has a zone factor of 0.10. There is no zone 1 in the Indian system.