DanG
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Quake, Steam Explosion Shake Mount St. Helens
| Quote From Source: | Geologist John S. Pallister was flying over Mount St. Helens when he spotted something unusual.
Pallister, a private pilot who works in the hazards section of the U.S. Geological Survey's Cascades Volcano Observatory, noticed a line of steam coming from a zipper-like fracture line atop the growing lava dome in the crater of the southwest Washington volcano.
After landing, he learned that a 2.9-magnitude earthquake had registered on seismographs at the observatory in Vancouver. That was followed by a small tremor that lasted nearly an hour and a half, an unusually long period, punctuated by a second quake of 2.7 magnitude — all in the same period in which he saw the steam.
All are typical signs that magma, superheated gases or both are moving through conduits beneath St. Helens, which blew its top with devastating force on May 18, 1980, leveling 230 square miles of forest and killing 57 people.
| | Click source url to view entire story. |
http://www.foxnews.com/story/0,2933,323372,00.html |
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apex
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Thanks for that, looks to be rather interesting. The www.pnsn.org looks to have some reasonably nice seismic traces on there of it.
http://www.pnsn.org/WEBICORD...C/HSR_SHZ_UW.2008011312.html
This ones clearer, must be further away than the first was.
http://www.pnsn.org/WEBICORD...C/SEP_SHZ_CC.2008011312.html
In case those links get invalidated when they update, I'll put it on photobucket.
http://i132.photobucket.com/...ei8/SEP_SHZ_CC2008011312.gif
http://i132.photobucket.com/...ei8/HSR_SHZ_UW2008011312.gif
Still, they aren't all that big, but you never can tell really, particularly not if the lava dome is expanding.
For reference, time of the first quake was around 10pm UTC, 13 Jan 08 |
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Indy
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Does anyone know if Mount St. Helens is capable of the same type of explosive eruption that obliterated Krakatau back in the day?
"I think God gives us children so death won't come as such a disappointment." - Two and a Half Men |
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MountainManMike
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possible but highly unlikely. |
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Indy
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I was reading about the history of Crater Lake today. That was a Krakatau type eruption. That massive cone is gone. Basically what didn't blow away got swallowed up by the caldera. I think the story said it ejected 50 km^3 of material.
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chrisisasavage
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Mazama was a WAY larger eruption than Krakatoa. Mazama, while not a Yellowstone or Toba type erruption, was absolutely massive for a Stratovolcano. I'm sure it caused some major climate change. |
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chrisisasavage
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Mazama also had something like 3 times the mass of Rainier. |
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chrisisasavage
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Rainier is probably a bigger risk of that kind of eruption than St. Helens. It's very rotten, and if it goes big, the whole thing could implode. |
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Indy
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I was looking up info on Rainier earlier and couldn't find anything to indicate that it ever blew big. But it is a massive mountain.
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chrisisasavage
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It's a massive mountain, and it's made of very rotten rock. It's one of the scare stories that makes the local papers here once in a while, that Rainier could implode and send enough earth toward Seattle to wipe it out. |
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Indy
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I've never understood building a large city in the footprint of such a massive volcano.
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chrisisasavage
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I think the Cascadia subduction zone is a bigger worry. Even then, I won't lose sleep.
A threat that's more likely to occur somewhat soon is an erruption of Mt. Baker or Mt. Hood. A good size eruption of either would be bad for Bellingham, WA and Portland, OR respectively.
An event like the Osceola Mudflow would be really, really bad for western Washington though. |
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MountainManMike
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lots of ice on rainier is the biggest scare that i hear about. all that melting would kill thousands. |
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FatalWishes
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No more grunge and we won't have a place to sell our old used worn out levis anymore.
They should take the warning labels off of everything and let stupidity sort itself out.
Please check out our new website at www.globalwarmingisnotreal.com |
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Indy
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No more Starbucks.
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DanG
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DanG has attached this image:
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chrisisasavage
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No more $4 cups of coffee?! OMG, what will the world do. |
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MountainManMike
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dont get me started on my dislike of starbucks... |
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Indy
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I admit I buy their beans at the grocery store but I have NEVER walked into one of their stores. And I refuse to ever do so.
"I think God gives us children so death won't come as such a disappointment." - Two and a Half Men |
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posted on 1/17/2008 at 10:09
