Oregon Public Broadcasting

Leading up to the anniversary of last year's tsunami off Japan, Oregon State University researchers are emphasizing the potential for damage here, from an off-shore earthquake.

OSU engineering professor Scott Ashford toured Japan after last year's quake. He says the greatest risk to human life from a major Cascadia Subduction Zone earthquake is the tsunami threat facing the Oregon Coast. But Ashford expects the Willamette Valley would endure sustained shaking of up to five minutes.

Michael Clapp / OPB

Ashford explains, "It's that strong shaking that's going to have a significant impact on our mobility -- our transportation system -- as well as our other lifelines: electric power, fuel, natural gas, and our water systems."

Geologists anticipate that the shaking would cause soils to liquefy and sap the stability of all kinds of infrastructure.

Ashford says damaged bridges would cut off the Coast from the Willamette Valley, and likely impair other major roads. State geologists are in the process of publishing new tsunami inundation maps for the Coast.

A state commission on seismic safety is expected to complete an Oregon Resilience Plan by the end of the year.