PORTLAND, Ore. (KOIN) — It’s no secret the Pacific Northwest is earthquake country — with the possibility of “The Big One” ever-present.
In fact, the last Cascadia Subduction Zone earthquake that resulted in widespread devastation was on Jan. 26, 1700, which produced a 9.0+ magnitude earthquake. The subduction zone, which runs from British Columbia to northern California about 70 to 100 miles off of the Pacific Coast shoreline, has resulted in 41 earthquakes in the past 10,000 years, according to the Oregon Department of Emergency Management.
Although obviously not as destructive as the 1700 quake, since 2000 Oregon has seen a number of strong earthquakes, according to data recorded by the U.S. Geological Survey.
The majority of large quakes have been recorded off of the Oregon Coast, with the largest being a 6.3 magnitude earthquake on Jan. 15, 2003. It was recorded at a depth of 10 km.
In 2008, another 6.3 magnitude quake, this time 242 km WNW of Bandon, was recorded at a depth of 13 km.
In 2019, another 6.3 magnitude earthquake was recorded, also WNW of Bandon on Aug. 29, which some KOIN viewers reported feeling.
In 2000, a 6.2 magnitude earthquake was recorded at a depth of 10 km off the coast of Oregon on June 2.
A 6.2 magnitude earthquake was recorded 272 km west of Bandon on Aug. 22, 2018, also at a depth of 10 km.
However, these strong earthquakes — the largest recorded in Oregon or off the Oregon Coast since 2000 — are not Cascadia Subduction Zone earthquakes. They are Blanco Fault Zone earthquakes, which occur when the Pacific plate slides north against the Juan de Fuca plate, according to KOIN 6 News Chief Meteorologist Natasha Stenbock.
A Cascade Subduction Zone earthquake is when the Juan de Fuca Plate moves under the North American plate, Stenbock said.
As for earthquakes on land, there has only been a handful to have an epicenter within Oregon’s borders since 2000, according to data from USGS.
In 2002, the residents of Government Camp on Mount Hood may have felt something shake when a 4.5 magnitude quake at a depth of 4.9 km hit on June 29.
Meanwhile, the latest 4.5 earthquake to hit land was one north-northeast of Port Orford on Nov. 30, 2019. It happened at a depth of 16.6 km. No injuries or damage were reported.