Earthquake in Leh: Reasons, Causes, Effects of recent frequent tremors in North India

On October 6, 2020, a tremor of 5.4 magnitude occurred in Ladakh at a depth of 10 kilometres. This was reported by National Centre for Seismology. There were no reports of injuries and damages.

Highlights

Ladakh also faced an earthquake of magnitude 3.7 on the Ritcher scale in late September 2020. Apart from Ladakh, other parts of North and North East India have also been facing frequent tremors. None of the tremors caused serious damages. However, the frequent occurrence of such tremors were a matter of concern in the country. This is mainly because in these earthquake zones of India, seismic activities are high.

Geological Survey of India

The Geological Survey of India says that the tremors have occurred due to foreshocks and swarms. A foreshock, mild tremor or swarm activities or a series of earthquakes indicate release of tectonic stresses during deformation process. Often such tremors are preceded by a major seismic event. A detailed study of these tremors will help to predict the major seismic event.

Observation

According to Geological Survey of India, minor earthquakes are mainly clustered in north western and north eastern Himalayan region. They were found mainly in Gujarat, Maharashtra and NCR regions, that is, over the areas that are demarcated as seismic zones IV and V.

What are foreshocks?

They are small earthquakes that precede a major larger earthquake at the same location. So far 40% of major earthquake events have exerted foreshocks.

Seismic Zones in India

The Bureau of Indian Standards has grouped the regions into seismic zones based on the past seismix activities. The zones are as follows

• Zone V: Very Severe intensity zone. Entire North Eastern India, Himachal Pradesh, Uttar Pradesh, Uttaranchal, Jammu and Kashmir, Rann of Kutch and Andaman and Nicobar Islands
• Zone IV: Severe Intensity zone. Delhi, Sikkim, northern parts of UP, WB, parts of Gujarat, west coast of Rajasthan and parts of Maharashtra
• Zone III: Moderate Intensity Zone. Lakshadweep Islands, WB, Gujarat, parts of Punjab, MP, Rajasthan, Jharkhand, Bihar, Maharashtra.
• Zone II: covers remaining parts of India

Month: Current Affairs - October, 2020