5.8 Earthquake 140 Off The Coast of Oregon

http://earthquake.usgs.gov/recenteqsUS/Maps/US10/37.47.-130.-120.html ^ | 07/09/02 | Norsewood

[NorseWood]

There seems to be a lot of siesmic activity off the coast lately. Is there a subsurface volcanic chain out in that area? Check this out: http://earthquake.usgs.gov/recenteqsUS/Maps/US10/37.47.-130.-120.html

[TADSLOS]

No, it's just Rosie out for a swim.

[Clara Lou]

That would be a fault, I imagine. Or maybe a very deep quake.

[DocCincy]

Well, it's not MY fault.

[Clara Lou]

Well, it's not my fault.
Can you prove it?

[dirtboy]

That's OK, I thought it was the Juan Exxon Valdez plate...

[Lou L]

Not a volcanic chain, but what geologists call a "subduction zone." It's where one plate slides beneath another. This sliding does cause volcanic activity inland, as represented by volcanoes such as Mt. Hood, and Mt. St. Helen's.

My college geo professor would be proud (I hope!)

[RightWhale]

Today is the new moon. Expect increased seismic activity due to tidal influences.

[Mike Darancette]

Or maybe a very deep quake.

10 KM deep.

[John H K]

No, out there, it actually is a volcanic chain (underwater, which has been active recently), but this earthquake was not related to volcanism.

The Juan de Fuca plate is one of the smallest plates in the World.

As you can see from:

http://neic.usgs.gov/neis/bulletin/neic_gjax_h.html

The earthquake was on the Pacific Plate/Juan de Fuca plate boundary; there is a spreading center connecting much of the two plates, but there are also "transform faults" where the two plates slide past each other, like the San Andreas does in California.

This quake was quite shallow, so it was simply the Pacific plate sliding sideways along the Juan de Fuca Plate. The subduction zone of the Juan de Fuca and the North American plate is well to the east, under Washington and Oregon.

[Lou L]

I stand corrected! Good thing that geology class was just an elective! :)