USGS reports six earthquakes off the coast of Oregon in the last week

August 1, 2012 – OREGON - Six earthquakes between magnitude 1.6 and 2.1 rumbled under the ocean less than 20 miles off the Oregon Coast in the last week, according to U.S. Geologic Survey records. The most recent – and most powerful – hit early Tuesday morning. And two quakes over 4.0 shook last week about 240 miles off Bandon. Small quakes hit Oregon on a regular basis, both on and off coast. Last Thursday, for example, a magnitude 1.4 shook 8 miles northeast of Springfield, and a 1.5 magnitude earthquake rumbled 11 miles east of Woodburn just before 9:30 a.m. Tuesday morning. But for residents of the Oregon Coast, earthquakes – and the tsunamis they can trigger – have taken on renewed importance since March 2011. The earthquake and tsunami that devastated parts of Japan last year caused damage on the Oregon Coast and continue to deliver debris to Northwest beaches. The USGS told KCBY News that the recent swarm of quakes pose little tsunami risk. The plates involved move sideways instead of up and down, and earthquakes under magnitude 6 are not likely to generate tsunamis. –KCBY

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7 Responses to USGS reports six earthquakes off the coast of Oregon in the last week

davidgreybeard says:

August 1, 2012 at 5:49 pm

While earthquakes of low magnitude are common here in Oregon, KCBY’s article is somewhat misleading. While the faults from roughly Crescent City southward are more strike-slip as they are the northward extension of the San Andreas, the Cascadia Subduction Zone, which runs from the southern Oregon coast all the up up to off of the coast of British Columbia, is called that because it is a subduction zone where one plate is riding up over the top of another. The Pacific Northwest is riding along on top of the N. Pacific plate, which is why the Cascades are a range of volcanic peaks. Subduction zones are some of the dealiest faults known (like the one east of Japan where last year’s quake occured), and while quakes under 6.0 aren’t known for generating tsunamis, the CSZ has a history of producing quakes in 7.0-8.0 magnitude range and still could. I guess that KCBY was trying to be reassuring, but I believe that people are better off hearing the truth ahead of time.

Adrian Alexander Bennett says:

August 1, 2012 at 7:32 pm

I’m interested to know, if there were any of those ‘unusual / bizarre booms’ heard before the quakes?

- davidgreybeard says:
  
  August 1, 2012 at 10:19 pm
  
  I haven’t heard of any and I live in this general area, but then, these were also small quakes.
  
Irene C says:

August 1, 2012 at 8:08 pm

This is one of the areas I’ve been keeping an eye on. Has definitely been active. I’m just praying that it’s releasing tension, not building up to something major.

- davidgreybeard says:
  
  August 1, 2012 at 8:53 pm
  
  Amen to that! It’s difficult to tell which one it’s doing, but I do start getting more concerned when there is a sudden swarm of activity in one spot like the area off of Brookings/Gold Beach that has lit up during the last 24-36 hours.
  
  - Barbara says:
    
    August 11, 2012 at 2:37 am
    
    Would you believe me if I told you that there is a purposeful, “out-side” man-made agitation being conducted to induce a large and destructive quake off of the Oregon Coast? That the heat, the mid-west drought and the unprecedented weather patterns are not “mother nature”?
laketown5 says:

August 1, 2012 at 10:55 pm

http://www.kval.com/news/local/Earthquake-swarm-a-few-miles-off-Oregon-Coast-164648806.html