SuperVolcanoes - Risk Update / Historical References
(Top Posts - Science - 072301)

The following news isn't good, at least not for those
around when, as anticipated, some time in the next
100,000 years, Yellowstone blows its top ... again ...

Source: University of Wisconsin-Madison (http://www.wisc.edu/)
Date: Posted 7/23/2001

Tiny Crystals Predict A Huge Volcano In Western United States

http://www.sciencedaily.com/releases/2001/07/010723101806.htm

Excerpt:

"MADISON - Reading the geochemical fine print found in
tiny crystals of the minerals zircon and quartz, scientists are
forming a new picture of the life history - and a geologic
timetable - of a type of volcano in the western United States
capable of dramatically altering climate sometime within the
next 100,000 years. ...

In a series of papers, UW-Madison geologists Ilya N. Bind-
eman and John W. Valley present a life history of the hot
spot volcanism that has occurred in the Yellowstone basin
of the western United States over the past 2 million years.
Their findings suggest a dying, but still potent cycle of vol-
canism, and a high probability of a future catastrophic erup-
tion sometime within the next million years, and possibly
within the next hundred thousand years.

Today's Yellowstone landscape represents the last in a
sequence of calderas - the broad crater-like basins created
when volcanoes explode and their characteristic cones col-
lapse - that formed in regular progression over the past 2
million years.

The near-clockwork timing of eruptions there - 2 million years
ago, 1.3 million years ago and 600,000 years ago - suggests
a pattern that may foreshadow an eruption of catastrophic pro-
portions, said Bindeman and Valley.

Beneath Yellowstone and its spectacular landscape of hot
springs and geysers is a hot spot, an upwelling plume of melted
rock from the Earth's mantle. As the plume of hot, liquid rock
rises in the Earth, it melts the Earth's crust and creates large
magma chambers.

"These magmas usually erupt in a very catastrophic way," said
Bindeman. "By comparison, the eruption of Mount St. Helens
sent about two cubic kilometers of ash into the atmosphere.
These catastrophic types of eruptions send thousands of cubic
kilometers of ash skyward." ..."

- - -

Further references:

"The last eruption in the Yellowstone Park area of
America occurred 600,000 years ago, resulting in
massive volcanic flood basalt flows, covering a
large area of the present-day northwest United
States. This is one of the largest supervolcanoes
in the world.

... The last supervolcano to erupt was Toba 74,000
years ago in Sumatra. Ten thousands times bigger than
Mt St Helens, it created a global catastrophe dramatically
affecting life on Earth. Scientists know that another one
is due - they just don't know when or where." (February
3, 2000):
http://www.bbc.co.uk/science/horizon/1999/supervolcanoes.shtml

- - -

"The evidence suggests that humans came within a cig-
arette paper's thickness of becoming extinct along about
this time." (May 26, 1999):
http://abcnews.go.com/sections/science/DyeHard/dye990526.html

- - -

"A hypothesis about recent human evolution suggests
that humans came close to extinction because of
a 'volcanic winter' that occurred 71,000 years ago.
Some scientists estimate that there may have been as
few as 15,000 humans alive at one time. The 'volcanic
winter' lasted about six years.

It was followed by 1,000 years of the coldest Ice Age
on record. It brought widespread famine and death to
human populations around the world. It also affected
subsequent human evolution." (September 8, 1998):
http://news.bbc.co.uk/hi/english/sci/tech/newsid_166000/166869.stm