It is May 18th, 31st anniversary of the May 18th, 1980 eruption of Mount St. Helens.
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It is May 18th, 31st anniversary of the May 18th, 1980 eruption of Mount St. Helens.
and the lesson is : active volcanoes are not tourist attractions
I don't know about that. What's the proximity rule for tourist vs. local?Originally Posted by marnixR
correction : active volcanoes may attract tourists, but shouldn't be tourist attractions
in the case of Mt. St. Helens what was thought to be a safe distance turned out to be anything but
Shouldn't we replace "active" with "erupting," for the last several comments?
Most of the Cascade volcanoes are active and pretty safe most of the time.
The geologists had told the governor that the Red Zone needed to be larger.
Most of the fatalities were local land owners retrieving belongings.
Dormant is the state of a volcano that is neither active, nor extinct.
This region is crazy active, most of them not only having recent eruptions but hot springs, steam vents and other signs that magma system is not far below:Originally Posted by GiantEvil
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unless a volcano is currently erupting, they are generally considered dormant actually. So aside from Mt St Helens the Cascade volcanos are considered dormant. Mt St Helens has entered another phase of dormancy with the cessation of the 2005-2008 eruption, and the next most recent eruption, if I recall correctly, was Lassen in 1917.Originally Posted by Lynx_Fox
I'll freely admit I'm no geologist, but that definition doesn't' fit any I can find. Most either site near magma, which is definitely true for most of the Cascade mountains, or has erupted in the near history, say the past 10,000 years, which most of the cascade volcanoes also fit.Originally Posted by Paleoichneum
http://www.theodora.com/geology/glossarya.html
http://www.ldoceonline.com/Geology-topic/volcano
http://volcano.oregonstate.edu/education/glossary.html
prior to its eruption, Mt. St.Helens wasn't actually erupting, but in imminent danger of doing soOriginally Posted by Lynx_Fox
i don't know how you differentiate that from non-dormant volcanoes that are not at that stage
I'm not sure either. My point is Saint Helen had many recent eruptions prior to 1980 and was already considered an active volcano. Many of the Cascade volcanoes are also considered active, most having erupted in the past several thousand years as well as showing many other signs of magma just below the surface. In those terms, the tourest comments didn't make sense, all these volcanoes are extremely popular and I've enjoy many of them personally. Imminent eruptions give quite a few warning signs with sufficient time to warn the populations of the increased danger.Originally Posted by marnixR
Of greater concerns for some of these, especially Ranier are sudden Lahars which might follow an earthquake or perhaps with no warning. Thousands live ontop of old flows. The worst might even reach Puget sound not only sweeping away parts of Tacoma but causing a Tsunami.
Perhaps we could have a system of Mauve, Saffron, or Taupe Volcano danger ratings?
The Newberry monument is Awesome! My only disappointment was that I didn't get to see any Crotalus oreganus. Maybe next time.
The Cascade Range volcanoes do attract tourists, especially (perhaps inadvisably) when they're "active".Originally Posted by marnixR
But we shouldn't forget about the biggest tourist magnet of them all - good old Yellowstone!
Hmmmm....should we consider it active or dormant?
The tourist brochure could read: "Come visit our volcano, but don't worry - the last time it blew up was 640,000 years ago :-D "
Chris
Active. Earthquakes, numerous hot springs and measurable changes to elevation at the surface all point that way.Originally Posted by CSMYTH3025
The discussions on this thread reveal the artificial character of our classification systems. There is a continual gradation from currently erupting volcanoes through to totally extinct. Where you put the dividing line is a matter of convenience or personal preference.
Is there an official chart?Originally Posted by Ophiolite
Not that I am aware of. MW's summary is as good as you are likely to get. The Cuillin's volcanic centre on Skye is not going to erupt ever again. It is as dead as John Cleese's parrot. It is truly extinct. As MW notes,, it is the distinction between active and dormant that holds most of the ambiguity.Originally Posted by GiantEvil
Mt. Pinatubo erupted as I woke up from bed many years ago live in the Islands. The sky was black as Armageddon with ashes all the way to your nose. A once in a lifetime horror event![]()
If I were a day younger, I would have no idea what that is supposed to mean. Nice to know one of the classics is still active and not extinct.Originally Posted by Ophiolite
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