There were no reports of damage after a 3.2 magnitude earthquake struck the metro area at 6:15 a.m. Monday.
Dozens of email and Web comments came in to The Columbian from those who felt the quake, including several reports from Salmon Creek and Felida.
By midday Monday, 206 people in the region had reported to the Pacific Northwest Seismic Network that they felt the quake on the “Did you feel it?” section of its website.
The tremor was centered about 12 miles below Kelley Point Park in north Portland. The park sits a few miles west of the Fruit Valley neighborhood in west Vancouver. A 2.1 magnitude earthquake was reported in the same area around 5:30 a.m. Friday.
Similar-sized quakes have been reported in that area since at least 1972. The last one of the same size was reported there in 1999, said Tim Walsh, chief hazard geologist with the Washington Department of Natural Resources.
“The earthquake is a little too deep to confidently tie it to a fault,” Walsh said. “There has been a fair amount of seismicity in that area over the years.”
The recent severe weather in the area is not connected to the quake, he added.
The earthquake may be associated with the Portland Hills Fault, which geologists think may be tied to a ridge and other geologic activity in the area, but the quakes are too deep in the ground to know exactly where that fault is, he said.
Mount St. Helens generally has one or two magnitude 2 or slightly higher earthquakes per week, which are usually not noticeable to people who live in the area.
The largest quake in the Mount St. Helens fault was a 5.5 on Feb. 14, 1981.
There’s no evidence that the Monday earthquake is connected to the Mount St. Helens Fault.
“Mount St. Helens is persistent,” Walsh said. “You get earthquakes there every day.”
Generally those living near the river or other areas with sandy soil will feel shaking from an earthquake farther away than those who live on bedrock or more compact ground, Walsh said.
It’s also unlikely that the fault is connected to the larger Cascadia fault system, which scientists have connected to a 9.0 earthquake in 1700, he said.
“At that location, the Cascadia interface would be 7, 8, maybe even 10 miles deeper,” Walsh said. “This almost certainly isn’t on Cascadia.”
Cheryl Bledsoe, emergency management division manager for the Clark Regional Emergency Services Agency, said 911 dispatchers received one call about the earthquake from someone in the Salmon Creek area. A few others said they felt the quake on the CRESA Facebook page, she said.
Did you feel the quake? Let us know in the comments or by sending an e-mail to metrodesk@columbian.com.