Delhi prone to quakes as it is near Himalayas, fault lines
It is important for people, local authorities to understand that there is no lead time to prepare for an earthquake because they cannot be predicted
Delhi is in an active seismic zone both because of the faults around the Delhi NCR region and its proximity to the Himalayas which are seismically active.
Experts at the National Centre for Seismology (NCS) said Delhi is categorised in seismic zone IV and needs to be on alert. It’s, however, also important for people and local authorities to understand that there is no lead time to prepare for an earthquake because they cannot be predicted.
“We cannot forecast earthquakes. There is no technology to do that. It really depends on when accumulated energy is released and at which fault. In the past few years, we saw epicentres to be near Delhi in 2008 and again in 2020. Several weak zones and faults are near Delhi. For example, the Delhi-Haridwar ridge, Mahendragarh-Dehradun subsurface fault, Moradabad fault, Sohna fault, great boundary fault, Delhi-Sargodha ridge, Yamuna River lineament, Ganga River lineament among others,” said JL Gautam, head of office, NCS.
“More importantly, Delhi NCR is located near the Himalayas which is a seismically active zone as we have explained in our report (on Tuesday’s earthquake),” added Gautam.
The Himalayan region is active because of collisional tectonics where Indian plate subducts beneath the Eurasian Plate.
HT had reported on June 4 that Delhi-NCR witnessed at least 14 earthquakes in around two months (March 24 to June 3). A 3- magnitude earthquake was recorded near Gautam Budh Nagar.
Also Read: 6.2 quake hits Nepal, Delhi NCR trembles under its effect
On Tuesday, a 6.2 magnitude (M) earthquake struck Nepal while its tremors were felt across north India, including Delhi and the NCR, Bihar and Uttar Pradesh on Tuesday at 2.51pm.
“It is noteworthy that prior to the main shock, three prominent events recorded on November 9, 2022 of M 6.3, January 24, 2023 of M 5.8 and February 22, 2023 of M 4.4 within 50 square km of today’s events which were also felt with slight to moderate intensity in Delhi-NCR and others neighbouring states,” NCS’s report on Tuesday’s earthquake said.
The report added: “The occurrence of earthquakes in the region is attributed mainly to the tectonic settings of the Himalaya comprising Himalayan Frontal Thrust (HFT), Main Boundary Thrust (MBT) and Main Central Thrust (MCT) besides several local faults and geological demarcated lineaments, the neighbouring states of India that felt earthquake shaking falls under the seismic hazard zones V and IV”.
On April 9, 2021, a statement by the science and technology department said scientists have found that the Himalayas are not uniform and assume different physical and mechanical properties in different directions – a property present in crystals called anisotropy which could result in significantly large earthquake events in the Himalayas.
“The NW region of India, an area covering Garhwal and Himachal Pradesh, has been hit by four destructive moderate to great earthquakes since the beginning of the 20th century -- the Kangra earthquake of 1905, the Kinnaur earthquake of 1975, the Uttarkashi earthquake of 1991, and the Chamoli earthquake of 1999,” the statement by DST and Wadia Institute of Himalayan Geology had said.
“These seismic activities manifest large-scale subsurface deformation and weak zones, underlining the need for deeper insights into the ongoing deformation beneath these tectonically unstable zones,” it added.
In the past, five earthquakes of Richer Magnitude 5.5 to 6.7 are known to have occurred in Delhi NCR region since 1720. Two major lineaments namely Delhi-Haridwar ridge and Delhi-Moradabad faults pass through the territory, both having potential of generating earthquakes. Normal depth of 30 km may be assumed for these earthquakes. It will be prudent to consider the effects of such a potential earthquake for developing a prevention-cum-preparedness plan, according to Delhi Disaster Management Authority.