PORTLAND, Ore. -- A magnitude 4.0 earthquake struck southwest of Molalla, Oregon on Wednesday evening. KGW viewers reported shaking across the metro region.
The earthquake struck at 5:24 p.m., about 10.5 miles deep, according to the Pacific Northwest Seismic Network. The epicenter was directly east of Scotts Mills, a town of about 350 people in Marion County.
There were no reports of injuries or major damage. The Marion County Sheriff's Office said deputies responded to the Scotts Mills area to check on residents as a precaution.
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A 4.0 magnitude earthquake is relatively minor, and not much damage should occur, according to U.S. Geological Survey geophysicist Rafael Abreu.
"If you're really close to the epicenter area it's likely to give you a pretty good jolt, but this is not the type of earthquake that we would expect to see any damage associated with it," he said. "Very typical quake for the Pacific Northwest."
Many people felt that "good jolt" Abreu referenced, from Salem up to Portland.
"Our house just started to shake a little bit, then a big boom happened," Briar Morgan, who was at home with his parents in Scotts Mills. "It felt like a water heater blew up."
An earthquake struck in nearly the same spot in 1993. That earthquake was called the "Spring Break quake" and had a magnitude of 5.6.
The Molalla area also had a 1.9 quake on Nov. 28 at about 3:40 a.m.; a 1.7 quake on Nov. 22 at about 3:15 p.m.; a 2.4 on Oct. 29 at about 12:05 p.m,; a 1.4 on Sept. 11 at about 7:40 a.m.; and a 1.9 on Sept. 6 about 1:36 p.m.
Seismologists expect an earthquake of at least a magnitude of 8.0 to hit the Northwest, with a one in three chance of "the big one" happening in the next 50 years. That earthquake is expected to cause widespread damage in Oregon and Washington.
Historical records show a magnitude 8.0 or higher earthquake has jolted the Juan de Fuca tectonic plate at the Cascadia subduction zone off the Northwest coast every few hundred years. The last big earthquake is estimated to have struck the Northwest around 1700.