Future Earthquake Risks
Are We in for the Big One?
The greatest regional potential for a large magnitude (M) earthquake,
estimated at M 8.0-9.0, is associated with the Cascadia Subduction Zone (CSZ).
The last major event in the CSZ is estimated to have occurred 300 years ago. Average recurrence intervals for this zone are predicted at 450 years, plus or minus 150 years. The earthquake in 1700 is believed to be the last significant seismic event for the CSZ.
There is no way to absolutely predict when the next event will be, but there is consensus that the Pacific Northwest is within the recurrence interval window.
What Does the Research Show?
Preliminary results from recent research lead researchers to believe that the
length of plate coupling, or zone where the Juan de Fuca and North
American Plates are locked together, may extend further east than
previously predicted. Because the maximum magnitude of an earthquake is a
function of the areal extent of the locked zone, there appears now to be a greater
likelihood of a large event along the CSZ. In addition, an eastward
extension of the locked zone also implies that events could impact large
population centers, such as those in the Willamette Valley.
For more information on the risk of future earthquake events in the Pacific Northwest, visit the following sites:
·The Oregon Department of Geology and Mineral Industries (DOGAMI)