This week, western Afghanistan was hit again by a major earthquake, just days after a number of major earthquakes in the same region claimed more than a thousand lives. Between 7 and 15 October, at least 5 major earthquakes and 23 aftershocks struck an area the size of Nordostpolder.
The catastrophic series of earthquakes began on Saturday, October 7, at 11:15 a.m. local time. Almost all the men were working on their lands or in the nearby city of Herat at that time. According to UNICEF, 90 percent of the victims were women and children. The strength of the first earthquake was 6.3 on the Richter scale. Half an hour later, a second earthquake measuring 6.3 magnitude followed. At twelve and a quarter, a third of 5.9 followed in the same area.
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Sam Gerrits is an earth scientist and science journalist.
Houses in Afghanistan’s villages are made of mud, a mixture of straw, manure, clay and sand. In a dry climate, thick walls have eternal life. They keep homes cool in the summer and warm in the winter. But they are particularly sensitive to earthquakes. They collapse at the first earthquake. At least eleven entire villages have disappeared from the map.
On Wednesday, October 11, at 5:15 a.m., the affected area was again hit by an earthquake with a magnitude of 6.3. This was followed by a fifth major earthquake on the morning of Sunday 15 October. Because everyone was now sleeping outdoors, “only” three people died this time.
Continental climate
The psychological impact of this series of mutations, in an area of 20 x 20 kilometers, is unprecedented. It is now rapidly getting colder in the dry continental climate, but frightened villagers are avoiding their homes. They spend the night in makeshift tents or outdoors. The panic has become much greater because no earthquakes have occurred in this part of Afghanistan in living memory. There is practically no help from the government. Since the Taliban came to power and cut off foreign aid, the country has entered a deep crisis.
These earthquakes were superficial, between 6 and 7 kilometers. This is unusual. Earthquakes usually occur at a depth of more than 10 kilometers in the Earth’s crust. It is caused by plate tectonics. Earth’s plates (giant puzzle pieces of the Earth’s crust) slide over each other, like skins of hot pea soup. Where they touch each other, rocks are compressed and mountains are formed. The shallower the earthquake, the greater the damage to the surface.
Herat fault
According to James Jackson, professor of plate tectonics at the University of Cambridge, this series of five major earthquakes in eight days is highly unusual. “There is a well-known fault in the Earth’s crust in this area, the Herat fault, but these earthquakes originated in the eastern extension of the Kopet-Dag mountain range.”
This Iranian mountain range, like the Himalayas, is pushed up and squeezed between the Eurasian tectonic plate and the Indian plate, but there is a “puzzle piece” in between that is usually inactive: the central eastern Iranian microplate.
Jackson: “The faults in all these mountains are under tremendous stress, but because many of them don’t normally move, they’re not well imaged. Faults that are constantly moving produce earthquakes and so can be mapped. If they’re not moving, you don’t know where they are.” Therefore, earthquakes in the mountains will continue to cause many casualties in the future.
