Following thirteen years of research, and taking four years to complete the study, researchers at Oregon State University, led by Dr. Chris Goldfinger of the University’s College of Earth, Ocean and Atmospheric Sciences, have had their results published online by the U.S. Geological Survey. The peer-reviewed analysis of the Cascadia Subduction Zone off the Pacific Northwest coast “confirms that the region has had numerous earthquakes over the past 10,000 years, and suggests that the southern Oregon coast may be most vulnerable based on recurrence frequency.” The study concludes that there is “a 40 percent chance of a major earthquake in the Coos Bay, Oregon, region during the next 50 years.”

Dr. Goldfinger said: “The southern margin of Cascadia has a much higher recurrence level for major earthquakes than the northern end and, frankly, it is overdue for a rupture. That doesn’t mean that an earthquake couldn’t strike first along the northern half, from Newport, Oregon, to Vancouver Island. But major earthquakes tend to strike more frequently along the southern end – every 240 years or so – and it has been longer than that since it last happened. The probability for an earthquake on the southern part of the fault is more than double that of the northern end.”

The report’s predictions are that any future earthquake could approach the intensity of the 9.0 magnitude Tohoku earthquake and tsunami that devastated northwestern Japan in March 2011. The press release from the University on the report notes that, “actuarial tables and history of earthquake strength and frequency may eventually lead to an update in the state’s building codes.”  Art Frankel, who has dual appointments with the U.S. Geological Survey and the University of Washington said: “We are considering the work of Goldfinger et al, in the update of the National Seismic Hazard Maps, which are the basis for seismic design provisions in building codes and other earthquake risk-mitigation measures.”