The mystery of the deadly Afghanistan earthquakes

Afghanistan has been hit by four high-magnitude earthquakes in under two weeks.

The quakes — all measuring around 6.3 on the Richter scale, which seismologists use to indicate the strength of an earthquake — occurred at relatively shallow depths of around 10 kilometers down, and wreaked widespread destruction.

In general, seismologists say visible damage can occur when quakes reach 5.0 or higher on the Richter scale. According to the European Commission's civil protection and humanitarian aid agency, since the first earthquake hit on October 7, some 2,400 people have died. Several hundred more are reported missing, and over 1,700 houses and 15 settlements have been destroyed.

Experts at the German Research Centre for Geosciences (GFZ) in Potsdam say more aftershocks are likely to hit in the coming weeks.

Although eastern Afghanistan is part of the so-called Himalayan arc, a zone highly prone to earthquakes due to its positioning along the Eurasian and Indian tectonic plates, the recent quakes occurred in northwestern Afghanistan, where tremors are generally rare.

Why is the Earth shaking in northwestern Afghanistan?

The past weeks' quakes shook the city of Herat and its environs, located in the northwest of the country. This region, which lies along what’s known as the Herat Fault, is largely considered seismically inactive. Past centuries have shown no historical evidence of similar devastating events, according to the GFZ.

"These were the first large earthquakes which have been detected in that region since official data are available at around 1900," the researchers wrote.

So far, geologists have only been able to guess what sort of seismic activity might have caused the recent quakes.

The researchers explained that less seismic stress builds up in the western part of the Hindu Kush mountain range (where the quakes occurred) than in its eastern part.

However, they wrote, the region likely experienced great seismic activity in earlier geological eras, before modern systems could track and record earthquakes.

"The fact that the western segment [of the Hindu Kush mountain range] was inactive for the last thousand years does not fully exclude the occurrence of future large earthquakes – as we can observe now," they wrote.

Call for more research

The GFZ scientists said the recent quakes "underscore the critical need for a thorough scientific study in the region."

The agency tracks earthquakes across the world, but said this has grown particularly challenging in many areas of Taliban-ruled Afghanistan due to decades of political unrest in the region.

"There is a limited number of seismic stations and no additional GNSS-satellite measurements at all at the western end of the Herat fault," they wrote. "This poses a significant challenge in accurately modeling these Afghan earthquakes and drawing reliable conclusions."

Edited by: Derrick Williams