John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
Last year’s temblor left enough energy in the ground to fuel another major disaster, say scientists.
The 7.8 earthquake that hit Nepal in April 2015 killed more than 8,000, moved the city 10 feet south, and crumbled innumerable buildings as if they were made of stale cake. Yet despite more than 100 aftershocks, there’s still enough pent-up energy below the ground to fuel another huge quake, according to a study in Nature Geoscience.
In the aftermath of the disaster, scientists rushed to the Himalayas to assess the situation. What they found was the quake didn’t create a visible tear in the earth’s surface. That was odd, given they thought the fault responsible had enough strain on it to cause nearly a dozen feet of ground-shift. That likely means there’s a great well of energy still pooled below the region, which future quakes can harvest with devastating consequences.
Here’s more from the University of Colorado Boulder about what might be lurking in the seismic pipeline:
Historical earthquakes in the region—in 1803, 1833, 1905, and 1947—also failed to rupture the surface of the Himalayan frontal faults and they, too, experienced a lack of afterslip or large subsequent earthquakes. That, according to the team’s research, means there’s significant strain throughout the region.
“There’s no evidence that it will spontaneously rupture in another damaging earthquake,” says [coauthor Roger] Bilham. “But the strain may fuel a future earthquake starting nearby. The entire Himalayan arc may host dozens of pockets of strain energy awaiting release in future great earthquakes.”
And this region remains vulnerable to earthquakes, not only because of its geography, but because of its architecture and development patterns. While this 2015 earthquake killed 8,000 people, left tens of thousands homeless, and destroyed parts of Kathmandu, the amount of strain built up in the faults, if released suddenly, could do much more damage in this part of the world.