The Reality of Earthquakes in Delhi and Himachal Pradesh

: Implication, Impact and Data Analysis of Earthquake 

Two earthquakes in Delhi during lockdown period serve as a reminder and warning to Delhi; whereas world is observing a massive reduction in seismic noise as much as 33 percent. Delhi is prone to major earthquakes as it already falls in a high – risk seismic zone. Our scientists fail to observe such a warning in the lockdown period.

“दिल्ली एन.सी.आर. के लिए यह भूकंप एक बड़ी पूर्व चेतावनी है” – “अलग अलग भूकंप विशेषयज्ञ”

During the lockdowns in the world and in India –there is a massive reduction in seismic noise being detected by seismometers around the world as indicated by Royal Observatory of Belgium, which makes it clear that earth is shaking continuously. Ground movements at frequency 1-20Hz, mainly due to human activity (cars,trains,industries,……etc) are much lower since the implementation of the containment measures by the governments . This has been a constant trend from March 31. In fact, their data suggests that these background noise levels have reduced by as much as 33 percent.

What are seismometers?
These are the detectors to pick up movements and activities in the earth’s crust; geological disturbances including volcanic activities and possible earthquakes. As most of the world and India is completely sitting indoors; scientists are able to collect cleaner and more accurate data. They are now able to predict any potential volcanic activity or earthquakes better.
Seismology in Washington DC, France, New Zealand and U.K. have also reported that the earth is less noisy during this “lockdown time”. Lots of our seismometers are seeing a drop in noise levels as human decreases.

Earthquake in Delhi
Low intensity earthquake hits Delhi – second quake in two days- on 13 April, 2020. The earthquake with its epicenter near Wazirpur in northeast Delhi occurred at 1.26 P.M. at shallow depth of 5 km – with magnitude 2.7. However on Sunday a moderate intensity quake of magnitude 3.5 hit the national capital at a depth of 8k.m.

J.L. Gautam head (operations); National Centre for Seismology told TOI that the two earthquakes in Delhi did not appear a result of fault line pressures. For these local and low magnitude earthquakes; these need not be a fault line, Gautam explained. Small adjustments take place underneath the surface, result in tremors. Larger earthquakes tend to occur along the fault lines. But Ramesh P. Singh; Ph.D, School of life and Environmental Science, Chapman University reports that efficient energy transfer from the epicenter of Sunday’s magnitude-3.8 quake northeast of New Delhi, along with quieting of urban noise due to COVID-19 lockdown made the quake noticeable by many in India’s capital region.

A small magnitude earthquake occurred near the NCR of India at 5.45 P.M. local time on Sunday. According to U.S. Geological Survey (USGS), the magnitude -3.8 quake originated at approximately 6 miles (10 k.m.) depth. Generally such a small magnitude quake is nondamaging, and on a normal day, most people would not even notice it. The USGS reports that in this case, the quake was widely felt.”

The region of earthquake lies in the eastern part of Indo-Gangetic river plain. The bulk of the plain is
thick pile of accumulated sediment deposit by Indus River over millions of years. Unlike sediments these hard rock types efficiently transmit seismic energy from the epicenter of an earthquake. It is likely that the hard basement rocks in Delhi-Haridwar Ridge play a key role in transmitting earthquake energy through the N.C.R. as per Dr. Ramesh P. Singh.

This quake should serve to remind local and national governments to consider earthquake preparation as a priority in the Indo-Gangetic basin. A larger –magnitude earthquake is expected in the Himalaya.
When and where it will hit, however, it is impossible to predict it's effect on the N.C.R. The government could try to deploy a dense network of GPS Stations in order to monitor and study the earthquake potential throughout the region, said Dr. R.P. Singh. But Himachal Pradesh jolted an earthquake of 4.5 magnitude on Sunday night, the meteorological department of state said, this was the sixth quake in three days in Chamba district. On Friday, five quakes of magnitude between 3 and 4.3 struck Chamba district before 30 March 2020 - during lockdown in India. Earthquake of magnitude 3.5 strikes East Delhi and neighboring areas according to the national centre for seismology. The quake occurred at 5.45 P.M. and its epicenter was NCR Delhi, at the depth of 8k.m.

The tremors lasted for 25 to 30 seconds on April 2020. The earthquake which occurred at a depth of 8k.m. was categorized in the “yellow slight” level , according to Ajay Kumar, officer on duty at the National Centre of Seismology (NCS)”.The earthquake was unexpected ; there were no sign of it coming –said Kumar adding he cannot say it will be followed by another set of tremors.”

Implication, impact, data analysis ,research and suggestions by Dr. Ram Bajaj

(1) Why there is difference of magnitude 3.5 at a depth of 8k.m. by National Centre of Seismology India and 3.8 at a approx. depth 6 miles (10k.m.) by USGS. Is this because of margin of error or something different in actual magnitude and epicenter?

(2) Why the earthquake was unexpected; and there were “no” sign of it coming –according to Ajay Kumar officer NCS ; it's duration lasted for 25 to 30 seconds.

(3) According to Dr. R.P. Singh“Efficient energy transfer from the epicenter of Sunday’s magnitude- 3.8 quake northeast of New Delhi, along with quieting of urban noise due to COVID-19 lockdown
 made the quake noticeable by many in India’s capital region.” But J.L. Gautam; National Centre for Seismology told TOI that the two earthquakes in Delhi did not appear to be result of fault line pressures. Small adjustments take place underneath the surface resulting in tremors.

(4) But Himachal earthquake of 4.5 magnitude & five others earthquake in Chamba district before 30 March 2020 – during lockdown in India along with two earthquake in Delhi during lockdown period where the world is observing a massive reduction seismic noise as much as 33 percent. But in my opinion these above quakes should serve as a reminder and warning to the governments to consider priority preparations – in the Indo-Gangetic Region Basin and specially in Delhi which is prone to major earthquakes, as it falls in high risk –seismic zone .

The high density of population and large number of high rises in Gurgaon and few in Delhi make the national Capital Region all the more risky. Most places along Yamuna and it’s flood plain , including highly populated residential colonies in east Delhi ,will be among worst –hit during an earthquake , according to a report of “seismic hazard microzonation “ of Delhi.

Email: info@rambajaj.com

 We can analyze and study the seismic activity beneath the soil in India. It is the best time to monitor and study seismic events in India. However India has not analyzed seismic noise reduction because of the lockdown yet and their impact on Delhi and the surrounding areas. Is there any co-relationship between Delhi's quake and Himachal's quake in March 2020?

Link To My Blog : https://inforambajaj.blogspot.com/

About The Author
Dr. Ram Bajaj
Engineer
Scientist
Agriculturist
Economist
Email: info@rambajaj.com