University of Arizona researchers use tree science to date Pacific Northwest earthquake
Download mp3 (1.51 MB)Scientists were unsure for decades whether to believe data suggesting that shallow faults near Seattle had ruptured together or in close succession.
Now, the University of Arizona-led research of tree rings has confirmed one or more major earthquakes occurred in the region 11 centuries ago this winter.
The seismic movement involved at least two of four shallow faults in the region.
There’s evidence of a tsunami in Puget Sound, widespread landslides and suddenly formed cliffs.
Rings of trees drowned in a lake formed by the event put it in the year 923 or 24 AD.
Study author Bryan Black is an associate professor of dendrochronology.
“And so we could have the divers get to the base of the trees and move away some of the mud where the trees are extremely well-preserved and cut samples of those trees," said Black.
Hear Bryan Black's interview with host Lauren Gilger on The Show
Co-author and associate professor Charlotte Pearson said there’s a mark found in trees worldwide left by a solar storm in the 8th century.
“And that’s going to give a second independent confirmation of the date and the fact that all of these trees are synchronous. They’re dying at the same time.”
The United Nations says two earthquakes of similar magnitude killed tens of thousands this year near the Turkey-Syria border.
