KATHMANDU, MAY 13 - Eighteen days after the magnitude 7.9 earthquake devastated the country, a major tremor was felt on Tuesday afternoon.
According to the National Seismological Center (NSC), an earthquake of 6.8 magnitude occurred at around 12:50 pm which was followed by a series of tremors ranging between 5 and 6.2 magnitude. The United States Geological Survey, however, measured the Tuesday’s temblor as 7.3 in Moment Magnitude.
The epicentre of the latest quake, according to the NSC, was somewhere between Sindhupalchok and Dolakha districts. The epicentre of the April 25 earthquake was in Barpak Village Development Committee of Gorkha.
Ranjan Kumar Dahal, a geologist with the Tribhuvan University, said that Tuesday’s tremor was the aftershock of the April 25 earthquake as it was generated along the same range. He, however, admitted that neither him nor his colleagues had anticipated that it would be this large.
“Aftershocks are common and tend to get less frequent with time along with decreasing intensity. But this one took us by surprise,” Dahal said.
Seismologists say that an earthquake of almost same magnitude as the main shock striking the same region in such short duration is “very rare”.
Given the history of earthquakes in the Himalayan region, seismologists say the movement of rupture was expected to travel
along the western region of Nepal where the stress has been building for over 600 years. But the recent earthquakes have displayed unusual characteristics.
“This is a unique and typical Himalayan earthquake. It is mysterious, given the nature of rupture propagation triggering the faults to result earthquakes along
the main shock impact region and now moving towards east,” said Deepak Chamalagain, a long time earthquake researcher.
Ross Stein, sceientist emeritus, USGS, had recently told the American National Public Radio that the aftershocks of the April 25 earthquake were striking on the neighbouring faults, causing it to rupture into susbsequent large earthquakes.
source:EKANTIPUR
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