The devastating quake that hit Nepal in April this year killed about 9,000 people and left thousands injured and homeless. But scientists say the quake did not release all of the stress that had built up underground, and has pushed some of it westwards. They have warned that there is an increased risk of a future major earthquake in an area that straddles the west of Nepal and India, reports BBC.
Prof Jean-Philippe Avouac, from the University of Cambridge, said:
“This is a place that needs attention, and if we had an earthquake today, it would be a disaster because of the density of population not just in western Nepal but also in northern India, in the Gangetic plain.”Advertisement
The 7.8 magnitude earthquake that struck Nepal occurred in a geological collision zone, where the Indian tectonic plate pushes north into the Eurasian plate, moving the ground an average of 2 cm a year.
The boundary between the two plates in this area had become locked – stuck together by friction, and rendered immobile – building up energy that only a major earthquake could release. However, the quake on April 25 only released part of this pent-up pressure.
The researchers believed that some of this stress has shifted west, to an area stretching from the west of Pokhara in Nepal to the north of Delhi in India.
A major earthquake there is already long overdue: the last happened in 1505 and is estimated to have exceeded magnitude 8.5.
The researchers have added that the new stress that has moved there could already be adding to the tension that has been building up over five centuries. Prof Avouac explained.:
“We don’t want to scare people, but it is important they are aware that they are living in a place where there is a lot of energy available. A lot of families are building their own houses in Nepal. With minimum care, it is possible to build small buildings that can withstand large earthquakes.”
Prof David Rothery from Open University said:
“Lives would be saved by drilling school children in western Nepal and the nearby plains of northern India in how to react in the event of an earthquake, and in ensuring that at least school buildings are adequately constructed to survive seismic shaking.”
Data from advanced GPS stations has also revealed that the death toll could have been far higher. Prof Avouac said:
“When I heard about this M 7.8 earthquake happening so close to Kathmandu, I was prepared for a death toll in the order of 300,000 or 400,000 people. But this earthquake didn’t generate a lot of high- frequency waves, which would have been devastating for the small buildings in Kathmandu. They could withstand the earthquake because of the characteristics of the ‘pulse’ – and its relative smoothness.”Advertisement