The massive earthquake of 7.7 to 7.9 magnitude that shook Nepal and several parts of North India close to noon today is a "shallow focus earthquake", that can potentially cause severe damage, a top seismologist here said.
The earthquake which occurred around 1141 hours this morning with epicentre at a distance of 77 km from Kathmandu, the capital city of Nepal, has a depth of 14-15 km.
The earthquake will set off aftershocks for the next 2-3 days till the entire energy is dissipated. Hence, there is need for vigilance and caution, said RK Chadha from the National Geophysical Research Institute (NGRI), Hyderabad.
It is the biggest after the 8.4 magnitude one that struck the Nepalese region in 1934. That earthquake caused severe damage in Kathmandu and also neighbouring parts inside India, Chadha told
The earthquake activity in the seismically active Himalayan region is due to the movement of the two tectonic plates--Indian and Eurasian plates. The 2004 tsunami inducing, Sumatra earthquake off Indonesia that cause widespread havoc has set off heightened seismic activity. This usually is active in 15 year cycles. Therefore, for seismologists the location and epicentre of the earthquake is not a surprise, said Chadha.
He said the impact of the earthquake could be felt across large parts of North and some western regions of India. Reports indicate people experiencing the effects in Delhi, Varanasi, Lucknow, Guwahati, Ahmedabad etc.
The NGRI, which has a very sophisticated earthquake monitoring centre connected to the global network has recorded data from over 20 stations and says the energy focus of the earthquake is towards the east-west direction in the Himalayan region.
The last significant earthquake hit Kathmandu region around 1988 with a magnitude of 6 with its epicentre towards Sikkim side of India, he said.
Here is the list of a few highest magnitude earthquakes in India and neighbourhood in the last 25 years.
1. January 26, 2001 in Bhuj, Gujarat. The 7.7 magnitude earthquake resulted in casualities of over 20,000.
2. October 5, 2005, the 7.6 magnitude Kashmir earthquake, which also impacted large parts of Pakistan. Huge human loss of 1.3 lakh.
3. August 10, 2009, the Andamans quake of 7.7 magnitude. Low human loss of 26.
4. March 29, 1999, the Chamoli, Uttarakhand earthquake of 6.8 killed 103.
5. September 30, 1993 Latur trembler, Maharastra killed over 10,000.
6. October 20, 1991 Uttarkhasi one of 7 magnitude. Deaths over 2,000.