Aerial survey of the Washington mudslide aftermath (Credit: King County Sheriff's Office)
Data from the University of Washington Pacific Northwest Seismic Network show no earthquake occurred before a landslide in Washington state, according to the U.S. Geological Survey. The slide occurred March 22.
Instead of pinpointing a causal link, data from the network indicate the extreme slide was not spurred by an external event. Two signals registered by the network show a first slip occurred at 17:37 Coordinated Universal Time, followed by a second land movement four minutes after.
There were reports of substantial ground shaking for over an hour after the landslide occurred. Those could have been confused with legitimate earthquakes.
Image: Aerial survey of the Washington mudslide aftermath (Credit: King County Sheriff’s Office)