If Wesnousky is right, the Arc may be ready to rupture in multiple locations, which could result in a series of great earthquakes similar to a recent earthquake sequence in Alaska where damaging earthquakes occurred in 1906, 1946, 1957, 1964 and 1965.
The 1950 magnitude -8.7 earthquake in Assam on August 15 may have begun a similar sequence in the Himalayas, says Wesnousky. The quake was destructive in both Assam and Tibet, killing 4,800 people. It was also notable for the loud noises reported throughout
the region.
“Sufficient stress has been accumulating in the Himalayas along the Main Himalayan Thrust for years,” Wesnousky adds. He says this pent-up stress could produce a sequence of megathrust earthquakes, with multiple events greater than magnitude 8.5 (M8.5).
Warrants Deeper Research “As horrible as it sounds, we should expect a great magnitude 8.5 (or larger) megathrust earthquakes to occur again in the Himalayas,” says Roland Burgmann, Professor, University of California, Berkeley, who was not part of this study. But Roger Bilham, a research scientist at the University of Colorado, Boulder, US, says that weakness in studies like Wesnousky’s is that available data only record one large earthquake. Researchers may want to see the paleoseismic record extended back 10,000 years — multiple earthquake cycles — at each location to determine the intervals between great quakes.
