Beneath the Himalayas sleeps a family of faults. For a long time, geologists have been aware that many within this 2,400-kilometer-long (1,500-mile) arc have the ability to decimate cities across some highly populous nations, including Pakistan, India, and Bangladesh.
Bhutan, though, which also lies along the arc, has always been considered unable to experience a significant earthquake. As a new study in Geophysical Research Letters reveals, this isn’t the case at all. In fact, the entire arc is “seismogenic,” in that it’s able to rupture at any point, including beneath Bhutan.
Until now, Bhutan had no detailed seismological records, so a team led by the University of Lausanne decided to investigate. It seemed unusual to them that this country was the only one along the arc to not have experienced a historical quake – except, weirdly, a 6.0M event in 2009.
While attempting to work out how the fault beneath Bhutan had unexpectedly moved, the researchers came across the biography of a Buddhist monk and temple builder by the name of Tenzin Lekpai Dondup. Remarkably, this document described a powerful earthquake in the region that took place in May 1714, one that was followed by plenty of aftershocks.
Frustratingly, though, it did not specify where the earthquake took place.
A costumed monk dances at Bhutan's Tsechu Festival. theskaman306/Shutterstock
However, at the same time, a separate study on the region revealed that some significant vertical fault movement took place in Bhutan that dated back to sometime between 1642 and 1836. Combining this discovery with his own team’s work, lead author György Hetényi – a geophysicist at Lausanne – managed to pinpoint the location of the 1714 quake.
Taking place in western Bhutan, the earth-shattering 7.5 – 8.5M event managed to unzip up to 300 kilometers (186 miles) of the fault line, which represents a whopping 8 percent of the entire arc. As significant as this is by itself, it importantly proves that the entire Himalayan arc can and has experienced powerful earthquakes.
“We are able for the first time to say, yes, Bhutan is really seismogenic, and not a quiet place in the Himalayas,” Hetényi said in a statement.