Why do Nepal quakes impact Gangetic plains? Here’s what experts say
New Delhi, Nov 4 (PTI) Earthquakes that hit Nepal have an impact on the Gangetic plains because the soft soil of the region amplifies seismic energy originating from the Himalayan belt, seismologists said.
On Friday night, a strong earthquake of magnitude 6.4 jolted Nepal sending waves of tremors across north India, including in Delhi-NCR. The National Centre for Seismology (NCS) had said the epicentre of the earthquake, which struck around 11.30 pm, was in Nepal, about 227 km north of Ayodhya in Uttar Pradesh and 331 km west northwest of Kathmandu.
It has claimed at least 143 lives and injured more than 150 in the Himalayan nation, and is the worst since 2015.
While seismologists warned that consecutive earthquakes are foretelling bigger seismic shocks in the western Nepal Himalayan region, an examination of the preliminary reports published by the NCS paint a geographical picture of the parts of India that experience these Nepal quakes and hence, are susceptible to them.
The centre issues such reports hours following an earthquake, detailing information about its epicentre and its depth, a preliminary analysis of the cause of the shocks, and the regions in India that felt the earthquake.
Its preliminary report on the November 3 seismic event said that it was widely felt in Delhi-NCR and neighbouring states. More than 90 "felt reports" were filed in from Delhi, Uttarakhand, Uttar Pradesh, Bihar and Haryana through the NCS' website and mobile app, the report said.
"The earthquakes in this stretch of the Himalayas will have a distinct impact on the Gangetic Plains and population centres such as Delhi-NCR because the soft soil of this region amplifies the seismic energy originating from the Himalayan region," CP Rajendran, Adjunct Professor, National Institute of Advanced Studies, Bangalore, said.
About the regions likely to be affected by future major earthquakes, "Indus-Gangetic-Brahmaputra Plains — from Jammu in the northwest all the way to upper Assam in the northeast — are all vulnerable," said Supriyo Mitra, Professor, Department of Earth Sciences, Indian Institute of Science Education and Research (IISER), Kolkata.
On the earthquake that hit Nepal on October 22, the NCS' report said that it was felt in Bihar. The epicentre of the seismic shocks (magnitude 5.3) was 72 km northwest of Kathmandu and at a shallow depth of 10 km, it said.
The seismic events in Nepal on October 3 were felt in Delhi, Uttarakhand, Uttar Pradesh, Bihar, Himachal Pradesh, Rajasthan and Punjab. "More than 70 felt reports had been registered in the hour following the strongest shock of magnitude-6.2, which had its epicentre 302 km east of Haridwar and 206 km southeast of Joshimath, and at a shallow depth of five km," the centre's report said.
Tremors were felt in Chandigarh, Jaipur and other parts of north India as well. PTI
