Mild earthquake jolts Capital amid lockdown silence

It’s not unusual for the epicentre to create relatively small tremors in Delhi and neighbouring Haryana, seismologists said. But this time the experience was much more intense for people in the national capital because of less noise associated with traffic movement, they said.

Delhi recorded an earthquake measuring 3.5 magnitude on Richter scale on Sunday evening with epicentre at Sonia Vihar in the national capital, according to the National Centre for Seismology (NCS) under the ministry of earth sciences.

People gather outside their houses after the earthquake measuring 3.5 on the Richter scale, near Mandi House, in New Delhi. (Arvind Yadav/HT PHOTO)

It’s not unusual for the epicentre to create relatively small tremors in Delhi and neighbouring Haryana, seismologists said. But this time the experience was much more intense for people in the national capital because of less noise associated with traffic movement, they said.

The seismologists at NCS also said that they had a “very good” recording of the event on their seismometer. “The recording is very clear because of no noise. People may have experienced the earthquake differently because most people are at home and not in a vehicle or not in movement. You can feel it the most during static conditions. I cannot comment on whether the sound heard (many people have reported to NCS that they heard a rumbling sound during the earthquake) is pertaining to the earthquake,” said AP Pandey, a seismologist at NCS.

“These are called tremors and very small earthquakes have been recoded in the past in the Jhajjar and Rohtak area. We are checking when was the last time the epicentre was within Delhi. We are in seismic zone 4 (severe earthquake intensity zone). We are close to the Himalayas where even magnitude 8 earthquakes can be recorded. The local soil quality also plays a role. Thick sediment soil in Delhi also amplifies the impact. The area where the epicentre is has newer alluvium soil which can record more tremors. It is close to the Yamuna belt,” said Pandey.

According to experts, the reason people felt strong tremors here is also because the depth of the earthquake is moderate (not very deep), the epicentre is in Delhi and there is very little ambient noise or vibrations induced by traffic movement. “We had an excellent recording of the event better than all our earlier recordings here. The signal strength was very high. The signal to noise ratio is perfect,” said G Suresh, another seismologist at NCS.

“Some people also heard a rumbling sound. That may be because of the energy released which interacted with atmosphere. Obviously, people have a clearer experience of the tremors when there is less noise and movement. We haven’t heard of any damage so far,” explained Suresh, adding “the earth quake was not very deep. This had a depth of less than 10 km.”