- 'N Yo' Seismic Network: Marshawn Lynch Shakes the PNSN!
- Swarms in Eastern Washington: are there fewer now than in the past?
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- ShakeAlert 2nd Anniversary!
- Pythia's Oasis
- Medford Schools Now Use Earthquake Early Warning Technology - And Yours Could Too!
- Magnitude 4.4 event of Oct 7, 2022
- 2024 3
- 2023 5
- 2022 9
- 2021 16
- 2020 5
- 2019 10
- 2018 11
- 2017 10
- 2016 16
- 2015 11
- 2014 16
- 2013 14
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2012
48
- December 1
- November 2
- October 3
- September 1
- August 3
- July 2
- June 4
- May 4
- April 2
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March
8
- 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
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February
7
- 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
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January
11
- 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
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- 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
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2011
17
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December
13
- 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
- March 2
- February 1
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December
13
Before people start running around yelling "eruption" after seeing the title of this blog I might suggest that they yell "boring" instead. Indeed there has been a bunch of small earthquakes taking place just south of Mount Hood starting today (Feb 23, 2012) just after noon local time. In the following three hours there were about 25 detectable earthquakes on the nearest seismic station, TDH.
Of these 14 were well-enough recorded to locate and have magnitudes between 0.1 and 1.8.
HOWEVER, this swarm is not that unusual.
The area just south of Mount Hood is known for a pocket (or nest, or school or hive) of earthquakes that occur in what we call, swarms. Over the past couple of decades there have been many such swarms. We have a brief summary of such swarms over the years including one swarm that had a few earthquakes greater than Magnitude 3. A paper published in 2005 (J. Jones and S.D. Malone, Mount Hood earthquake activity: volcani or tectonic origin, Bull.Seis. Soc. Amer. #95, 818-832, linked here) studied the early swarms in great detail. While not being able to absolutely rule out a volcanic connection to the generation of these earthquakes, this study concluded that these events were most likely due to regional tectonic stresses just like most earthquakes in the Pacific Northwest.
I would not be surprised if there were more events in this swarm. Some past Mount Hood swarms have lasted for only a few hours but most have gone on for at least a few days. We will be keepng an eye on it to make sure that nothing truly unusual takes place, but in the meantime....... boring.