March 8, 2013
by Steve Malone
Following the major northern Washington-Vancouver Island ETS (Episodic Tremor and Slip) from July 30 until Oct 12, 2012 there was a reasonably large ETS in northern California from Oct. 15 until Nov. 10. The subsequent three months had comparatively little tremor anywhere in Cascadia; an average of less than 60 hours of tremor per month scattered in small bursts all over. Then beginning about Feb 12 with a three day burst in northern Puget Sound followed by scattered bursts in northern California lasting four to five days activity started really picking up on March 1. Strong tremor just south of Portland Oregon spread south-west for a few days and then is moving south almost to Corvalis now. A few days ago a strong burst started near the Oregon-California boarder and then yesterday there was a strong burst in the southern Puget Sound area under Olympia.
This map shows tremor locations over the past month (Feb 8 - Mar 8). Color coding is by time (blue is oldest, red youngest).
The central Oregon batch bares watching. This is the part of Cascadia for which full ETS episodes are fairly rare (from 18 to 23 months between them compared to 12 to 15 months for northern Washington ones and 9 to 12 months for northern Californa ones). If the current central Oregon activity is the beginning of a full ETS then it should last for another few weeks and extend south to the Roseburg area. The last major ETS in this region was in June, 2011, so one is about due.
Of course all deep tremor bursts may be associated with slip. However, until the geodesits can actually measure it we don't usually concider it a full blown ETS. We will need to wait until the geodetic data are in and processed and a card-carrying geodesist has blessed it before it is offical. In the mean time anyone can follow the progression of this event on our Interactive Tremor Map which is updated nightly.
- Packers versus Seahawks game analysis -- too exciting
- Panther versus Seahawk Game Analysis
- Seismology will again watch/help the Seahawk's playoff run
- Canadian ETS morphing to Washington one?
- Great ShakeOut, Great success!
- The Great ShakeOut 2014 is Tomorrow!
- Three Cascadia ETS events in past month??
- Is Mount St. Helens seismicity increasing?
- Warm weather triggers snow avalanches at St. Helens
- Seismic recordings of a gas explosion in North Bend, WA
- 2015 (3)
- November (1)
- October (2)
- September (1)
- July (1)
- May (1)
- April (1)
- March (2)
- February (3)
- January (4)
- October (1)
- September (1)
- August (1)
- June (1)
- April (3)
- March (4)
- February (1)
- January (2)
- December (1)
- November (2)
- October (3)
- September (1)
- August (3)
- July (2)
- June (4)
- May (4)
- April (2)
- The wech-o-meter takes over all of Cascadia
- Keystone Cops: Italy prosecutes seismologists for failure to predict deadly quake
- UFOs in eastern Washington? No, rather UTEs (Unidentified Terrestrial Events)
- New Sodo Seattle Liquefaction Array Installed
- Why we should constantly watch the deformation of the seafloor
- Mystery chirp near Newberry Volcano
- Planting seismographs causes earthquakes? or maybe ice-quakes?
- Tunneling rumbles south under Capitol Hill
- 15 years of mostly silent magma inflation near Three Sisters, Oregon
- Mount Hood earthquake swarm of Feb 23, 2012
- Web glitches: duplicate (and even triplicate!) earthquakes
- How earthquake magnitude scales work
- Mine blast masquerades as volcanic tremor
- The Spokane Swarm about 10 years ago
- Another hum around Mount St. Helens
- Slow slip: A new kind of earthquake under our feet
- PNSN and social media
- 3am M3.4 earthquake in St. Helens Seismic Zone
- The wrong kind of volcano noise
- Fast chatter on Rainier an hour ago
- Can slush-mageddon trigger earthquakes?
- Rainier Repeating Earthquakes Update and Comparison with Weather Patterns
- 22-minutes drumbeat icequakes(?)
- Mount Rainier popping away
- Repeating Earthquakes on Mount Rainier - are glaciers the culprit?
- Debunking another SEC football myth by the PAC-12
- One year ago, Seattle Seahawks 12th Man Earthquake
- The odds this year of a megaquake on the Pacific Northwest coast
- Is the plague of great earthquakes this decade a sign of increased danger?
- Nile Valley landslide talks to PNSN seismologists
- Good vs evil in central US earthquake hazard analysis
- Why does a volcano scream?
- Predicting big quakes from patterns of little ones
- 1-hour warning for Japanese M9 earthquake?
- Sound Transit train under Interlaken keeps a rollin'
- Invisible changes under the hood at the PNSN
- Sound Transit Tunneling Noise
- "Visionary" toads
- Earthquake early warning in the PNW
- November (1)
- December (13)