The April 25 Nepal earthquake killed more than 8,000 people and caused several billion dollars in damage, but new research suggests the toll could have been a lot worse.
GPS readings taken during the quake indicate that most of the tremors vibrated through the ground as long shakes rather than quick pulses. That largely spared the low-lying buildings that make up much of Nepal’s capital, Kathmandu, geophysicists report online August 6 in Science. Those same low-frequency rumbles, though, toppled Kathmandu’s handful of larger buildings, such as the historic 62-meter tall Dharahara Tower.
Understanding why the fault produced a quake at such low frequencies could help seismologists better identify future seismic hazards, says Jean-Philippe Avouac of the University of Cambridge. “This could be some good news not only for this major fault, but also potentially for similar faults around the world.”
Nepal sits over a tectonic boundary where the Indian Plate slips under the Eurasian Plate. At places, the two plates snag together, building stress that abruptly releases as an earthquake (SN: 5/16/15, p. 12).