How bad would quake damage be here?
PORTLAND, Ore. - Despite strong building codes here a major earthquake in the Northwest, like the one that struck Chile, would still cause widespread devastation in the Portland area, experts say.
In downtown Portland tall buildings would shake violently, winds could carry glass as far as a half mile away, rubble would be everywhere, and there would be casualties.
The geographic area of Oregon and Washington makes them vulnerable to the exact type of earthquake Chile experienced over the weekend. This is because 75 miles off the Oregon Coast is the Cascadia subduction zone where the Juan de Fuca plate is diving beneath the continent.
Geologists have already identified 19 past earthquakes off the Oregon and Washington coasts estimated at greater than 9.0 which were stronger than the 8.8 Chilean earthquake.
Geologists say the quakes off the Oregon and Washington coasts happen every 250 to 500 years, and the last one was about 300 years ago.
Oregon state geologist Vicki McConnell said it’s only a matter of time when the area is hit like the one that struck Chile. “It could be anything from a 7.0 to a 9.0 plus,” she said.
There are also faults through downtown Portland and on the east side of the city which could generate quakes near a magnitude of 7.0.
Information on those faults and their probability of failure is not as up to date as the more powerful faults off the coast.
But earthquakes generated from the faults in Portland could also pose huge problems for the area because of landslide dangers and outdated bridges and buildings.
According to Keith Berkery, of the Portland Office of Emergency Management, 1,900 buildings, most made of brick and mortar, were erected before nationwide seismic regulations went into effect in 1971.
“Unfortunately for us it’s an uphill battle, because people don’t pay attention to the fact that it can happen here and that there is 10,000 years of geologic history that says it is going to happen here,” Berkery said.
Your local Office of Emergency Management teaches classes on earthquakes.
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