Could A Major Earthquake Hit Delhi Soon? Seismologist Kusala Rajendran Answers

Amidst a full-blown pandemic, a series of earthquakes have rocked the National Capital Territory and raised fears in the hearts of people. Yet another earthquake of 4.3 magnitude on rocked the national capital area on the night of December 17. The epicenter of this recent earthquake was 48 km southwest of Gurgaon. This takes the number of earthquakes since June to 12, as per Hindustan Times. In a year which is already marred by a pandemic and as human beings we realise that our hands are tied in front of natural calamities earthquakes can really cause panic.

Many have suggested that it is a precursor to a big one. There have been serious questions if Delhi is equipped to handle a strong earthquake. However, earthquakes remain curious occurrences and we cannot predict when the next one will occur.  To clear out apprehensions we spoke to well-known Indian seismologist Kusala Rajendran who is a Professor at Centre for Earth Sciences in Indian Institute of Science Bangalore. Kusala assures, there is "Nothing unusual" with what is happening in Delhi right now.

Here are some edited snippets from our conversation with  Kusala Rajendran.

Delhi has witnessed an unusual number of mild earthquakes recently; can you explain the reason behind it?

Nothing unusual. Delhi is located in the proximal region of the great, active plate boundary, the Himalaya that has resulted from the collision of India and Eurasia plates. Tectonic stresses in the Himalayas due to the continuing convergence of the two plates get transmitted also to the south, to the plains. Old faults that exist there occasionally release such accumulated stress, leading to earthquakes.

As is being said, do smaller earthquakes indicate that a big one is around the corner? Should Delhi Earthquakes Worry us?

If that was so true universally, it would not have been difficult to predict earthquakes. While it is possible that on some larger fault systems which might also have associated network of smaller faults, there could be foreshocks leading to a larger shock. But this is not a norm. One can have many small tremors not leading to any major earthquake (e.g. Palghar, Khandwa) and one can have a large shock with no smaller precursors. This is a reflection of the structural and tectonic setting of the concerned region. I do not see that possibility for Delhi.

One can have many small tremors not leading to any major earthquake (e.g. Palghar, Khandwa) and one can have a large shock with no smaller precursors.

Studies have suggested that Himalayan foothills are in danger of an imminent earthquake. What can be the effect of such an earthquake on Delhi?

History gives us enough examples for such events. For example, the 1934 Bihar (M ~ 8)  and 1803 Kumaon (M ~ 7.6) earthquakes have caused shaking in Delhi. The 1803 earthquake is reported to have damaged the Qutub Minar.  One has to recognize that the density and style of buildings in Delhi remain untested to such shaking. Yes, a great Himalayan earthquake can be devastating for Delhi, considering the large density of people and buildings and that there is the thick alluvial deposits of the Gangetic plain that tend to amplify the seismic energy.

Also Read: Why are there fewer women in STEM?

We have read in our school geography lessons that in the Himalayan region, two tectonic plates are meeting each other. Can you explain the implications of this for a common reader?

Large earthquakes occur along plate boundaries. A plate boundary is the result of collision of two plates, in this case the Indian and Eurasian plates.

This is the manifestation of the global tectonic process that moves the nearly 100-km-thick upper part of the earth (known as the lithosphere) slide past each other and where they meet each other they either collide to form mountains (as the Himalaya) or if the two plates are of different densities, the denser one dives down (as in the Andaman Sumatra region). Such plate boundaries are the most active seismically, globally.

Can prediction of an earthquake make us safe? How can we prepare for an earthquake?

Prediction involves a warning on where, when, and how big an earthquake is and enable people to be evacuated. There is no method anywhere in the world that enables accurate prediction of earthquakes. It is possible to identify the potential regions of future earthquakes and even estimate likely magnitudes. But the time of occurrence is beyond prediction. So, scientists suggest windows like in the next 50 years, etc.

There is no method anywhere in the world that enables accurate prediction of earthquakes. It is possible to identify the potential regions of future earthquakes and even estimate likely magnitudes. But the time of occurrence is beyond prediction.

Tell us a bit about yourself, what made you study Geophysics and get into research. There are very few women who went for STEM subjects back then, did you face any gender biases.

My choice of geophysics was by chance, not by design. I had gone to the University of Roorkee with the intention of joining for MSc chemistry but chance took me to the department of earth science. I got admission there also and after listening to fascinating lectures by Prof. Vinod Kumar Gaur, professor of Geophysics I changed my mind and took up Geophysics.

I believe that a lot of things in my life happened by chance. There are many young students out there who are aged below 20 or just about that age and are confused about what to do. That is normal. My view is that if you are good and if you decide to, you can succeed. In other words, if you are a good player you can turn the game around.

Earth Science is a male-dominated profession. I was the only girl in my class when I did the M.tech at Roorkee. I have had limitations especially because of the nature of my work, like going to the field etc. But I have not experienced any discrimination; nothing more than the usual level that women in all professions feel. How many times do we see women as chairs of selection committees? How many women are directors, vice-chancellors, etc.? And where they come to the top they do so well. So it is the general setting that I like to comment about, not any personal experience.

Earth Science is a male-dominated profession. I was the only girl in my class when I did the M.Tech at Roorkee.

What You Should Know

• During an earthquake, if you are indoors you should drop to the ground; take COVER by getting under a sturdy piece of furniture; and be there till the shaking stops. If can’t take cover then, cover your face and head with your arms and crouch in an inside corner of the building.
• Stay in bed if you are there when the earthquake strikes. 
• If you are outdoors when an earthquake strikes stay there. Move away from buildings, streetlights, and utility wires.
• If you are moving on the move stop without compromising your safety and stay in the vehicle. Avoid stopping near or under something that can collapse like buildings, trees, overpasses, and utility wires.

What would you like to tell young women who want to study STEM subjects?

Whatever you do, whatever branch of study you choose, learn to love it. Be passionate about your work.

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Prof. Rajendran prefers to call herself an Earth scientist because she believes "Study of earthquakes is not just about reading seismograms and interpreting the physics of earthquakes. It also involves a broader understanding of the earth processes and ability to study the earthquake effects from the field."

Kusala was born in 1954 as the ninth child in a family of ten. She grew up in Thalayolaparambu, a small village in Kerala. Her father was a leading Congress Party politician and her mother was a homemaker. In 1976, she completed a five-year undergraduate course at St. Teresa’s College in Kochi, graduating with a major in chemistry. She was fascinated by organic chemistry and dreamed of becoming a cosmetic chemist one day. Her sister and her brother in law were the first people to suggest she should switch to geophysics. But it was her first Geophysics lecture which made the decision for her, however she remained the only female student pursuing the course. She says the opportunity to join the Indian Institute of Science as a faculty, was one thing that helped her fulfill her dreams.