After two powerful earthquakes with a magnitude of more than 7 struck Nepal in April and May, several seismologists around the world had predicted that the Himalayan region would experience more such temblors.
Scientists had said that the quakes in Nepal – with magnitudes of 7.9 and 7.3 – had not have released all the pent-up seismic pressure in the region and that it could take scores of 7-magnitude quakes to accommodate all of the motion between the Indian and Asian tectonic plates, the Live Science journal reported.
After the first massive quake struck Nepal on April 25, geologist Eric Kirby of the Oregon State University said some 33 to 50 feet of motion may need to be released.
Researchers Eric Hand and Priyanka Pulla had warned in the leading journal Science that the Nepal tremors had “extended deep into the Himalayas, into a region that many scientists had deemed incapable of explosive tearing”. The discovery suggested that future quakes in the Himalayas could end up being mightier and more calamitous than modellers had assumed.
“The earthquakes in this region can be much, much larger,” Walter Szeliga, a geophysicist at Central Washington University, was quoted as saying by Live Science.
“We have the potential for bigger earthquakes than we might have otherwise expected,” Gavin Hayes of the US Geological Survey told Science.
Rich Briggs, a USGS research geologist had told Wired magazine after the May 12 earthquake in Nepal it would be ridiculous to say the region is shake-free from here on. “The readjustment in (geological) stress could play out in days, weeks, months or decades – we just don’t know, there remains a potential for large earthquakes in the region.”
Why Hindu Kush?
According to US Geological Survey, at the latitude of the Monday’s earthquake, the India subcontinent moves northward and collides with Eurasia at a velocity of about 37 mm/yr.
“The April 25 quake, and its subsequent aftershocks, including a particularly severe one on May 12, represent part of the cycle of strain accumulation and release along this plate boundary, related to the continued northward motion of India with respect to Eurasia,” Gavin Peter Hayes, a research geophysicist with the USGS told IndiaSpend.
Geophysicist at the University of Leeds, Tim Wright, told IndiaSpend that the Nepal quakes rearranged the region horizontally and vertically, pushing Kathmandu up by a metre and a half and pushing down many of the surrounding high peaks by between half a metre to a metre.
These geological displacements are continuing, caused by the activity of the Indian plate–a raft of the earth’s crust that bears the subcontinent–as it grinds into what is called the Eurasian plate, the Asian landmass.
Minor quakes in Hindu Kush
Data sourced from THE India Meteorological Department’s earthquake reports shows several minor quakes occurred this year in the Hindu Kush region of Afghanistan, where Monday’s 7.7-magnitude temblor had its epicentre. At least 12 earthquakes with magnitudes of more than 5 hit the region until September, with tremors being felt in north India.
Here is a list of earthquakes in Delhi’s neighbourhood in 2015 (Only magnitude of 5 or above):