By Vibhuti Agarwal:
A sweep of the western Himalayas in India, Nepal, Pakistan and Afghanistan is at risk from earthquakes as strong as magnitude 8, geologists warn, as pressure mounts between the India and Eurasia tectonic plates.
An earthquake of that strength in an area with densely-populated, poorly constructed cities and towns “would turn into a major disaster,” according to a recent report by India’s National Institute for Disaster Management.
Quakes that struck Nepal in 2015 killed nearly 9,000 people as an eastern portion of the main Himalayan thrust moved. But they weren’t large enough to release all the tension building up below the earth’s surface.
A sweep of the western Himalayas in India, Nepal, Pakistan and Afghanistan is at risk from earthquakes as strong as magnitude 8, geologists warn, as pressure mounts between the India and Eurasia tectonic plates.
An earthquake of that strength in an area with densely-populated, poorly constructed cities and towns “would turn into a major disaster,” according to a recent report by India’s National Institute for Disaster Management.
Quakes that struck Nepal in 2015 killed nearly 9,000 people as an eastern portion of the main Himalayan thrust moved. But they weren’t large enough to release all the tension building up below the earth’s surface.
And it happened like clockwork — in geological time — in the spring of 2015, a week after an international conference in the capital Kathmandu to discuss ways to prepare for a significant seismic event.
By some calculations, a quake of magnitude 7.8 radiates enough energy to power New York city for just over a month, or to electrify the average U.S. home for more than 330,000 years.
“The area east of Kathmandu seems unlikely to rupture again in the near future in a large [greater than 7.5-magnitude] event,” according to a paper published in Nature Geoscience by scientists from the Department of Earth Sciences at the University of Cambridge and the Earth Observatory of Singapore, among others .
Now, scientists are focusing on the area west of the Nepal quake where the plates are still described as locked.
It is possible that the 2015 earthquake “failed to rupture the locked portions of the Himalayan thrust beneath and west of the Kathmandu basin because of some persistent barrier of mechanical and structural origin,” it added.
Consequently, the “stress could be released by afterslip,” leaving the potential for the locked portion to produce a large earthquake, the study said.
The most-recent significant earthquake there occurred in 1505, according to the researchers, making them even more sure that the region is due for another one soon.
The size of the 16th-century temblor is debated, with some estimates saying it exceeded magnitude 8.5, and caused significant damage in Tibet.
The gap between huge quakes doesn’t mean the region–one of the most-seismically active in the world — hasn’t experienced smaller ones.
Early Wednesday, a 5.6-magnitude quake struck south of Jarm in Afghanistan and was felt in Islamabad in Pakistan. Last week, Imphal, the capital of Manipur state in the northeast of India was hit by a 6.7-magnitude quake that killed 10 people and injured 120, while on Friday, Afghanistan experienced a 5.0-magnitude earthquake.
In October, a magnitude 7.5 quake struck east of Farkhar in Afghanistan, also in the region where the two unrelenting plates meet.
A report published by India’s National Institute of Disaster Management last week said that over half (58.6%) of India was prone to earthquakes of moderate to very-high intensity. Six major earthquakes have struck the country in the past 15 years.
“The entire Himalayan region is considered to be vulnerable to high-intensity earthquakes of magnitude exceeding 8,” the report said.
The most earthquake-prone parts of India include the northeast, northern parts of Bihar, Uttarakhand, Himachal Pradesh, Jammu and Kashmir, Gujarat and the Andaman and Nicobar Islands.
India’s capital, Delhi, isn’t at such high risk of an earthquake but could experience tremors if a large one struck further north, experts said.
Bikram Singh Bali, a seismologist and professor at the University of Kashmir said he has long-warned of a major 8.2-magnitude quake in the Himalayan belt that includes Pakistan, Afghanistan and Jammu and Kashmir.
Prof. Bali said his research, conducted jointly with the University of Colorado between 2007 and 2012, suggests that “The catastrophe is already overdue.”
The accumulation of geological stress in the region is ongoing, like a spring being pushed tighter and tighter together, said B. K. Rastogi, director-general of the Institute of Seismological Research in Ahmedabad.
“We don’t know yet when and where it will reach the elastic limit. It might happen today or 50 years later,” he said.
blogs.wsj.com
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