We seem to focus on the Yellowstone Caldera, but there are in actuality three active calderas in the United States. Yellowstone is by far the largest. Then we have Long Valley Caldera which is an active, and restless caldera as well. New Mexico has the Valles Caldera, and although considered active, I have yet to find any reports that is in a state of unrest.
I believe that most people would be surprised to know that the United States has three super volcanoes which are active. The term super volcano is a relatively new term, one which could be considered somewhat alarmist on one hand, and yet a very definitive description on the other.
The swarms at Yellowstone seem to have calmed down...for now. Still, as I have said before, I believe that it is in the early stages of eruption. Early stages for an eruption for a volcano that blows approximately every 600,000 years can take a while. Could it erupt without warning? With the unrest Yellowstone has displayed for a good number of years, I believe that we do not know enough to predict an eruption. Once the eruption is imminent and geologists agree the thing is gonna blow....I believe it would be to late for any sort of evacuation. Even if you COULD give warning to evacuate, how do you evauate the entire states surrounding this massive volcano?
Yellowstone and the other calderas, are mysteries. And will likely remain that way throughout time. The destruction a massive eruption would create would likely destroy any and all data on the caldera and make it virtually impossible to pass that information along to future generations. The destruction it would create on earth would be massive. Not just in the United States....but world wide. Life as we know it, would change. All things considered, it is roughly estimated to be 40,000 years overdue for an eruption. That does not give me a warm and fuzzy feeling.
Another interesting discovery I found was that there is a very large volcano which lies directly under the entire city of Jackson, Mississippi. The center of this volcano is 2900 feet below the Mississippi Coliseum. It was discovered in 1819 and they say it has been extinct for over 65million years. Earthquakes can occur in Mississippi, and the largest one known was in 1931. It was located in the Batesville-Charleston area and was felt in Alabama, Arkansas, Tennessee and Missouri. The greatest risk to Mississippi, where earthquakes are concerned, are from the New Madrid fault. The lower portion of this fault is about 40 miles Northwest of Memphis. Should a large earthquake occur in that area, considerable damage could be expected throughout Mississippi. What does that mean for the volcano which lies beneath Jackson which is said to be extinct?
A new fault was just discovered near Marianna, Arkansas which poses a threat of a 7.0 or greater earthquake. It is interesting to note, that the new fault and known New Madrid Fault put that area into a very dangerous area for major quakes. What affect, if any, could these fault lines have on the extinct Jackson volcano?
An extinct volcano has not had an eruption for at least 10,000 years and is not expected to erupt again in a comparable time scale of the future. Extinct volcanoes have been cut off from any magma flow.
However, from what I have read, it is possible for humans to THINK an extinct volcano may never erupt again because the time between eruptions is so long. Could a major earthquake change the status of an extinct volcano allowing the magma flow to resume?
It is difficult to distinguish between dormant and an extinct volcano. An extinct volcano is considered extinct because there is no "written" record of its activity. Volcanoes may remain dormant for a very long time, thus we consider them extinct. It has happened that so called "extinct" volcanoes have erupted.
Still, my guess it is that is not a common event, but if I lived in Jackson, I would sure hope they monitor that thing from time to time.
That being said, I would keep a very close eye on the Long Valley and Yellowstone calderas. They are restless, full of magma and show all the signs that an eruption is coming....we just do not know when.
An active volcano is a volcano that has had at least one eruption during the past 10,000 years. An active volcano might be erupting or dormant.
An erupting volcano is an active volcano that is having an eruption...
A dormant volcano is an active volcano that is not erupting, but is expected to erupt again.
An extinct volcano has not had an eruption for at least 10,000 years and there is no written record of past activity. Based on this criteria, is not expected to erupt again in a comparable time scale of the future.
For more on Yellowstone please take a few minutes and read The Yellowstone Newspaper.
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