Delhi ready for 'Great Himalayan Earthquake'? Decoding seismologists' warning for National Capital Region

Earthquakes in the Himalayan region occur when Indian plate collides with the Eurasian plate. These tectonic collisions lead to fault lines with major geological strain.

A shallow 4.0 magnitude earthquake shook entire Delhi-NCR in early morning hours on Monday. What followed were series of minor tremblors that were reported from Bihar, Odisha and all the way to Sikkim. While there were no reports of any injury or loss of property due to the low intensity, the Monday tremors have brought back the ‘Great Himalayan Earthquake’ in the spotlight. Seismologists have been warning about a massive tectonic shock in the eco-sensitive region for quite some time now. Since the 2015 Nepal Earthquake, scientists have been saying that an earthquake of magnitude 8 or above will strike the Himalayan belt impacting the Gangetic plain sometime. Ace geophysicist Roger Bilham has been saying that it is not a question of what but when.

In an interview to Times of India, Bilham had said that Himalayas have been experiencing major earthquakes ‘every few hundred years.’ In the past 2,000 years, the Himalayan region has seen several earthquakes at a regular interval. Most of these tremors have been of magnitude 8.7.

But the expert had said that in the past 70 so years, Himalayas have not reported any earthquake above the intensity of 8 on the Richter Scale. For the record, the devastating earthquake of Nepal was of 7.8 magnitude. The Kathmandu earthquake had killed 9,000 people and parts of the Nepali capital was totally flattened.

When is the ‘big one’ coming?

Earthquakes in the Himalayan region occur when Indian plate collides with the Eurasian plate. These tectonic collisions lead to fault lines with major geological strain. Only a massive earthquake will be able to release the tension, experts say. In his research paper, Bilham had said that there is an alarming absence of a big earthquake that can help in the easing of strain in the Himalayan Arc. A 2018 study by Indian scientists had predicted that the next big Himalayan earthquake may hit the region between Dehradun and western Nepal. Researchers at Jawaharlal Nehru Centre for Advanced Scientific Research in Bengaluru had analysed several major earthquakes that had hit India and adjoining nations in the recent past. On the analysis of Gujarat and Nepal earthquakes, the researcher had said that there is a significant tectonic build-up in the region.

Is Delhi ready for major earthquake?

A 2019 report published by the National Disaster Management Authority showed that Delhi falls in the IV zone of India’s seismic map. Delhi’s seismic risk is due to the presence of Delhi-Hardwar Ridge. This geological structure coincides with the extension of the Aravali Mountain belt under the Ganga basin. From Delhi to Shimla, major Indian cities are at a high risk.

Why future Himalayan earthquake is so dangerous?

Seismologists believe that the next big earthquake in the Himalayan region will be particularly destructive as it will hit the landmass. It will directly impact the lives of over 300 million people. The land-based setting makes the Himalayan earthquake very, very dangerous. Urban infrastructure is more vulnerable to the violent shaking in the event of a mega-quake.