Yesterday a local pilot and well known mountain photographer, John Scurlock reported spotting avalanche debris in the east breach of Shurman Crater on Mount Baker. To quote John's e-mail: "the upper east face of Sherman Peak on Mount Baker had shed its huge buildup of snow in an avalanche that went down into the east breach of Sherman Crater and then on down Boulder Glacier". John provides us with his impressive photo of the source zone for this avalanche taken on Oct 27, 2013. (All photos are copy righted by John Scurlock)
The seismograms for this event are from MBW, located about 6 km due west of Mount Baker and SHUK, located at the Mount Baker ski area about 11 km to the east-northeast.
MBW
PDT Oct, 21, 2013
SHUK
PDT Oct 21, 2013
We also show spectrograms for these two stations and for RPW, located about 24 km to the southeast. Spectrograms show the frequency content of the seismic signals (vertical axis) versus time (horizontal axis) with the strength of the signal as colors going from blue (weak signal) to red (strong signal). This spectrogram is a preview of the type of information we will be routinely providing on our PNSN web pages in the future.
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It is interesting to compare this event with a previous known similar event that took place on Jul. 25, 2006. Again, photos by John Scurlock show that the source zone is very similar to the recent avalanche but may have involved less material. Note the size of the debris pile in the east breach.
The amplitude on the seismograms from station MBW is consistent with the recent event being larger. The duration of the signal is similar but the amplitude of the 2006 event is significantly less.
More information about this event and similar ones can be found on the Mount Baker Volcano Research Center web site.
It seems that the expected ETS of Oct-Nov, 2013 is already underway. Significant tremor started on Sep 7 in south Puget Sound and has already moved into southern Vancouver Island. This one seems both early and speedy with strange jumps. Update on Oct 11, 2013: It is over. This one went from Sep 7 - Oct 8, 2013. For all the details of this whole event......
A series of M3 earthquakes are shaking the area of Mount St Helens, in one of the more vigorous bursts of seismic activity in a few years.
Say "jokulhlaup" three times real fast and then run up-slope to get away from it. This icelandic word describes a sudden release of water trapped in a glacier. Such sudden floods can rapidly "bulk up" with sediment scavenged from river banks generating a lahar (mud flow) that can be very dangerous and destructive. Such an event occurred in the early morning hours of May 31 from the Deming Glacier down the Middle Fork of the Nooksack River and was well recorded by the MBW seismic station of the PNSN.
To address our users' desire for a simple user interface to view the latest earthquakes in the Pacific Northwest, we have just released three features: a new recent events list, mobile views, and a Twitter feed that will tweet all PNSN events magnitude 2 or greater.
Deep event is typical of seismicity near Seattle, has some aftershocks.
The ETS in central Oregon starting on Feb 24 seems to have finished on Mar 31. But, bursts of tremor continue in other parts of Cascadia. In fact during the Oregon ETS much of Cascadia has seen periods of tremor lasting from one to several days.
It has mostly been seismically quiet recently, although last night and this morning a swarm has been active in southern Oregon.
A workshop with 50 people met last month to chart the path to Earthquake Early Warning in the Pacific Northwest. Progress is encouraging.
The PNSN's in-depth blogs are here, and meanwhile our liveliest discussions on happening on Facebook.
Following three months of relatively little deep tremor in Cascadia the past month has seen bursts of activity up and down the region including what appears to be a full blown ETS starting in northern Oregon and spreading south.
Though the residents of Gold Bar may not have noticed, a swarm of hundreds of tiny earthquakes has been rumbling along just a few kilometers east of town since October 2012.
The Last Cascadia Great Earthquake and Tsunami; 313 Years and Ticking
January 24, 2013
by Bill Steele
The last great Cascadia Subduction Zone Earthquake occurred 313 years ago. We need to do more before the next one strikes.
Reports of a bright flash in the sky in eastern Washington this morning caused us to search seismograms for stations in the area which turned up what seems to be a "sonic" source that weakly was recorded on 9 seismographs. It is fairly common for bright flashes in the atmosphere, sometimes referred to as "fireballs", "meteors" or "bolides" to end up being recored seismically. Such recordings can allow us to pinpoint the time and location more accurately than can be done from eyewitness reports.
This has been a mild year, and our volcanoes have been well mannered, too.
Comments on Portland seismicity by PNSN staff seismologists.
Since Paul and I arrived in Seattle in 2006, there have been no quakes bigger than M4.5 in Oregon or Washington, and probably not because we are effective quakepolice.
New webicorder or "Seismogram" pages are now available for every channel of every instrument the PNSN maintains, and a few more. You once had to visit the UW Seismology Lab to get these data.
Most States in the US and countries around the world will join in a massive Duck, Cover and Hold earthquake drill Thursday, 10/18 at 10:18. Please join in! Where ever you are, "Duck, cover, and hold" at 10:18 am and do one more thing that day to get better prepared for the next big quake.
Geothermal project starts soon. We forecast some small quakes near Newberry Volcano.
October 3, 2012
by John Vidale
A novel experiment in mining energy from hot rocks is starting in a few days on the flank of Newberry Volcano, which may generate signals on nearby PNSN seismograms and small earthquakes in our catalog.
Thousands of coastal residents impacted by the Great Cascadia Subduction Zone Earthquake of 1700 shared their experience in stories and art.
Last Saturday, August 18, 2012 at 11:07:36 PM a magnitude 5.5 earthquake occurred east of the the Juan de Fuca Ridge, 253 km (157 miles) SW of Tofino, Canada. Several aftershocks followed. Some PNSN web site regulars were disappointed, even alarmed, that the earthquakes were not displayed on our recent earthquake map.
The next batch of Episodic Tremor and Slip (ETS) should be starting in Washington in the next month or two. In fact, after watching the Wech-o-meter for a few days I thought it might have already started early like the one last year did. But, about the time I was preparing to run around yelling that it had started, the tremor stopped. In e-mail discussions with tremor experts, Ken Creager and Aaron Wech about "has it started yet" we digressed into more arcane ruminations of what is an ETS and should we even talk about them. To become as confused as we are or bored out of your head .....
Seeing Through Rocks: Seismic Imaging of the Cascadia Subduction Zone
August 3, 2012
by Kate Allstadt
A glimpse into our local Cascadia subduction zone using marine seismic reflection imaging
Some like it hot - but that's not how it is.
Recent Posts
- Large Mount Baker debris Avalanche this fall
- Speedy ETS in the works
- Peppy seismic swarm 20 km NW of Mount St Helens
- Glacier outburst flood on Mount Baker recorded by the PNSN
- Three new ways to view recent earthquakes in the Northwest
- M3.5 event west of Tacoma early Sunday morning
- Oregon ETS is over, but....
- Small swarm near Mount McLoughlin last night
- Earthquake early warning workshop quick report
- thePNSN Facebook discussions
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