USGS Discusses U.S. Discoveries Related to Historical Quakes and Tsunamis

Averting Surprises in the Pacific Northwest

"The mighty Pacific Northwest earthquake lasted a minute or more and seemed to go on forever. Soon after the shaking stopped, a roar along the Pacific coast announced the oncoming tsunami--a series of huge ocean waves caused by the earthquake. Years later, survivors would tell their grandchildren about endless shaking and the sea that surged far ashore. But most stories were eventually lost, and people forgot that this earthquake had ever struck the region. For the earthquake happened about A.D. 1700, generations before the words of native Northwesterners were first written down.

"Past occurrences of very powerful earthquakes in the Pacific Northwest went unrecognized by earth scientists until the mid-1980's. Had such an earthquake occurred earlier in this (the 20th) century, Northwesterners would have been taken by complete surprise. Now, warned by earth scientists, residents of the Pacific Northwest have taken new steps to reduce their vulnerability to future earthquake losses. Earthquake design standards in Oregon and Washington have been toughened, and many existing structures have been reinforced."