Posted on 09/26/2004 7:11:09 PM PDT by rdl6989
September 26, 2004 3:00 P.M., PDT
Seismic activity at Mount St. Helens has changed significantly during the past 24 hours and the changes make us believe that there is an increased likelihood of a hazardous event, which warrants release of this Notice of Volcanic Unrest. The swarm of very small, shallow earthquakes (less than Magnitude 1) that began on the morning of 23 September peaked about mid-day on 24 September and slowly declined through yesterday morning. However, since then the character of the swarm has changed to include more than ten larger earthquakes (Magnitude 2-2.8), the most in a 24-hr period since the eruption of October 1986. In addition, some of the earthquakes are of a type that suggests the involvement of pressurized fluids (water and steam) or perhaps magma. The events are still occurring at shallow depths (less than one mile) below the lava dome that formed in the crater between 1980 and 1986.
(Excerpt) Read more at vulcan.wr.usgs.gov ...
Yeah, the one time in known history that the Cascade fault shifted, it created that nice Harbor on the coast there..
Beautiful!
Which is why I bought earthquake insurance...
Depending on where you live, it may not matter.
If you haven't researched the Cascade fault, I'd recommend it. I'll see if I can find the web site that discusses it.
Essentially, when the Cascade fault slips, it is massively destructive, creating a tsunami that they believe reached Japan 500 years ago, and dropping large chunks of the land into the water. The difference between this and other quakes is that the other quakes are quick, short jolts lasting only about a half minute. They say when the Cascade goes, it will last at least 5 minutes, which will create a series of massive waves through the earth's crust. Earthquake-reinforced buildings are built to withstand a jolt. They can't withstand the waves, though, and most will come down.
Thanks...all that taken sitting in a car with my little Sony Clie NZ90. a really really beautiful area...
Gosh. I'll have a nice view of the end of the world from my 22nd floor office as it tumbles down the hill into Eliot Bay...
Here is a good site for quake-related info in the PNW:
http://www.pnsn.org/INFO_GENERAL/INFOSHEET/welcome.html
Yikes!!!!
Here's a site with lots of quake info:
http://www.pnsn.org/INFO_GENERAL/INFOSHEET/welcome.html
I accidentally posted it to myself!
Hmmm. If you do find and post that web site would be mind giving me a ping? I live about 40 miles from St. Helens (as the crow flies) and about 8 miles from the base of Mt. Adams, right smack in the middle of the Cascades. Guess I better fasten my seat belt, again.
At 3:08pm Monday 9-27-04 a 2.6 quake occured under the mountain.
Here is a link that give real time info on the quakes there.
http://earthquake.usgs.gov/recenteqsUS/Maps/US2/45.47.-123.-121.html
See post 89. There are quite a few links on that page. Also, if you go to the home page of the story posted at the top of this thread, you can find more information.
I wouldn't worry, but it's good to keep an eye on these things and keep your basic 1-month survival supply fresh and up-to-date (as it should always be maintained).
Actually, it isn't the home page, but two branches down.
Here is the 'home' page of the Cascades portion of the USGS site:
http://vulcan.wr.usgs.gov/Volcanoes/Cascades/
"So y'all are kinda like the scene in Mordor when they can see Mt. Doom in the distance :)"
I can see Mt. Rainier out my kitchen window...
Mama
Also, Ghost, your advice regarding a month supply of provisions is a good idea. We always try to have a one year supply. Always better to have it and not need it, etc.
Sounds like a nice view.
On Monday, a helicopter lowered a geophysicist onto the lava dome to replace a failed instrument used to measure tiny movements that indicate whether the dome is swelling, Winn said.
http://www.msnbc.msn.com/id/6092368/
Pic updates once every five minutes. What is really interesting is that this site has been DOWN for a couple of years and was rushed back online about the same time as that swarm of quakes started up!
Someone expecting something perhaps?!?!?!
At least they're more or less prepared at St. Helens. After the last blow the cities downwind (Yakima, Richland/Pasco/Kennewick, etc) were buried in a horrible, gritty ash that choked automobile engines and turned the sky night-dark. Pantyhose and cheesecloth around the air filters kept some people going for awhile but the gunk had to be cleaned out at frequent intervals.
Good luck to all there. You got a bunk if you live to reach Idaho...
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