Re: Super Volcano Will Challenge Civilization, Geologists Warn

From: Ralph Nesbitt (ralph-nesbitt_at_sbcglobal.net)
Date: 03/11/05 

Date: Fri, 11 Mar 2005 03:10:09 GMT

"George" <george@wtfiswrongwithyou.com> wrote in message
news:Bo2Yd.114354$tl3.30265@attbi_s02...
>
> "Mitchell Jones" <mjones@21cenlogic.com> wrote in message
> news:mjones-AF1252.14022310032005@spectator.sj.sys.us.xo.net...
> > In article <tNVXd.112165$tl3.47688@attbi_s02>,
> > "George" <george@wtfiswrongwithyou.com> wrote:
> >
> >> "Mitchell Jones" <mjones@21cenlogic.com> wrote in message
> >> news:mjones-6D5586.03201710032005@spectator.sj.sys.us.xo.net...
> >> > In article <KDkXd.106968$4q6.35205@attbi_s01>,
> >> > "George" <george@wtfiswrongwithyou.com> wrote:
> >> >
> >> >> "Ralph Nesbitt" <ralph-nesbitt@sbcglobal.net> wrote in message
> >> >> news:vlkXd.5668$YD4.3931@newssvr12.news.prodigy.com...
> >> >> >
> >> >> > "George" <george@wtfiswrongwithyou.com> wrote in message
> >> >> > news:B3jXd.106001$tl3.73377@attbi_s02...
> >> >> >>
> >> >> >> "Ralph Nesbitt" <ralph-nesbitt@sbcglobal.net> wrote in message
> >> >> >> news:PFiXd.5464$YD4.5286@newssvr12.news.prodigy.com...
> >> >> >> >
> >> >> >> > "Bunn E. Rabbit" <BunnERabbit@verizon.hutch.net> wrote in
message
> >> >> >> > news:eh6r215d807vfodff79751vn4s4theed45@4ax.com...
> >> >> >> >>
> >> >> >> >> Grab those adult diapers!
> >> >> >> >> --
> >> >> >> >> Bunn E. Rabbit
> >> >> >> >>
> >> >> >> >> -----------
> >> >> >> >>
> >> >> >> >>
http://www.livescience.com/forcesofnature/050308_super_volcano.html
> >> >> >> >>
> >> >> >> >>
> >> >> >> >> Super Volcano Will Challenge Civilization, Geologists Warn
> >> >> >> >> By Robert Roy Britt
> >> >> >> >> LiveScience Senior Writer
> >> >> >> >> posted: 08 March 2005
> >> >> >> >> 06:30 am ET
> >> >> >> >>
> >> >> >> >> The eruption of a super volcano "sooner or later" will chill
the
> >> >> >> >> planet and threaten human civilization, British scientists
warned
> >> >> >> >> Tuesday.
> >> >> >> >>
> >> >> >> >> And now the bad news: There's not much anyone can do about it.
> >> >> >> >>
> >> >> >> >> Several volcanoes around the world are capable of gigantic
eruptions
> >> >> >> >> unlike anything witnessed in recorded history, based on
geologic
> >> >> >> >> evidence of past events, the scientists said. Such eruptions
would
> >> >> >> >> dwarf those of Mount St. Helens, Krakatoa, Pinatubo and
anything
> >> >> >> >> else
> >> >> >> >> going back dozens of millennia.
> >> >> >> >>
> >> >> >> > http://dutchman.nmt.edu/Geop/magma.html is a candidate for a
"Super
> >> >> > Volcano
> >> >> >> > Eruption".
> >> >> >> > Ralph Nesbitt
> >> >> >> >
> >> >> >>
> >> >> >> According to the study at the link below, "The measured uplift
rate is
> >> >> >> a
> >> >> > few
> >> >> >> millimeters per year in the center of the anomaly. Available
> >> >> > geomorphologic data
> >> >> >> indicates that the crustal uplift may have continued in Socorro
at a
> >> >> > similar
> >> >> >> rate for the last several tens of thousands of years. " So, it
doesn't
> >> >> > sound
> >> >> >> like it is likely to erupt in the near future.
> >> >> >>
> >> >> >> http://sioviz.ucsd.edu/~fialko/res_socorro.html
> >> >> >>
> >> >> > Agreed, but this is still one of the largest known magma bodies in
the
> >> >> > world. There has been significant volcanic activity north of
Sorocco .
> >> >> > Ralph Nesbitt
> >> >> >
> >> >>
> >> >> Current activity, as in eruptions? Is it bigger than the magma body
> >> >> beneath
> >> >> Kilauea?
> >> >
> >> > ***{The magma chamber beneath Kilauea appears to be in a roughly
> >> > circular pool with a flat surface about 2 miles beneath the caldera,
and
> >> > a less smooth bottom surface about 3 miles further down. Horizontal
> >> > radius is about 6 miles. There is a vertical channel about a mile
wide
> >> > rising up from the mantle and connecting roughly at the center of the
> >> > magma chamber, with the throat extending on upward to the caldera
from
> >> > the top of the magma body. See
> >> >
http://www-personal.engin.umich.edu/~pmcheng/engineering/research/tilt.ht
> >> > ml for a cut-away diagram, in color no less. See also
> >> >
http://www.brunel.ac.uk/departments/geo/iainsub/studwebpage/boon/magic.HT
> >> > ML. The surface area overlying the Kilauea magma chamber would
therefore
> >> > be about pi(6)^2 = 113 mi^2, as compared to the 5000 mi^2 area
overlying
> >> > the Socorro magma reservoir. Letting pi r^2 = 5000, we find that r =
40
> >> > miles for the Socorro chamber. If it has the same ratio of depth to
> >> > radius as the Kilauea reservoir, it will be 20 miles deep. Volume
will
> >> > be 20(5000) = 100,000 cubic miles of magma, whereas the volume of the
> >> > Kilauea reservoir would be 3(113) = 339 cubic miles. Thus the Socorro
> >> > reservoir would be roughly 100,000/339 or 295 times as large as the
> >> > Kilauea reservoir. --MJ}***
> >>
> >> Thanks for the links. I think you've overestimated the size of the
> >> magma body for Socorro.
> >
> > ***{Oops. The Socorro numbers should have been metric: that's km, not
> > miles. The Kilauea numbers were miles, and the last reading I did before
> > I wrote up the post was about Kilauea, so I was thinking in terms of
> > miles when I wrote up that estimate. Volume of the Socorro reservoir
> > would therefore be 100,000 km^3. A km^3 is {(1000)(39.37)/[(12)(5280)]}
> > = .24 mi^3, so a better estimate would be 24,000 mi^3 for Socorro.
> >
> > Also, my estimate was based on the surface area of the Socorro seismic
> > anomaly, which may be larger than that of the magma body itself. At
> > http://dutchman.nmt.edu/Geop/magma.html the estimate for the surface
> > area of the magma body was 3400 km^2. If you want to use that, the
> > Socorro radius becomes 33 km and the depth becomes 16.5 km, giving a
> > volume of p r^2h = pi (33^2)(16.5) = 56,100 km^3, or 13,464 mi^3.
> >
> > Any way you slice it, this sucker is huge!
> >
> > --Mitchell Jones}***
> >
> > According to the data at the link I
> >> provided above, the estimated volume of the Socorro magma
> >> body is at least several thousand cubic kilometers. I don't know
> >> how much "several thousand cubic kilometers is, but it appears
> >> to be less than one hundred thousand cubic miles.
> >
> > ***{Yup. "At least" indicates a low end estimate, and would also be
> > lower than 56,100 km^3. The problem is in the estimate of the vertical
> > extent of the reservoir. At the dutchman link, above, no estimate of
> > vertical extent is attempted, so I made what I considered to be a
> > reasonable guess: that the Socorro reservoir had the same ratio of depth
> > to radius as the Kilauea reservoir. Other estimates for depth give other
> > estimates of volume. You have to make the depth very small, however, to
> > get the volume down to "several thousand cubic kilometers," since
> > "several" would surely be less than ten. Let's see, using 10,000 km^3
> > for volume, we obtain pi(33^2)h = 10000, and the depth turns out to be h
> > = 2.92 km, which is a mere 1.8 miles. That's roughly half the depth of
> > the Kilauea reservoir, and in my opinion is utterly preposterous. The
> > guy was being way too conservative when he made that estimate. --MJ}***
>
> Hmmm. Didn't the first article say that the magma body was 19 km deep?
Why use
> 2.94 km in your calculation? If it is 19 km deep, and you use the ratio
for
> kilauea, wouldn't 19 km be the shallow depth, and therefore the deep part
of it
> would be deeper than 19 km? At least, that is the way I read it. The
following
> article indicates that the magma body may be on the order of 10^2 - 10^3
meters
> thick, and is a sill or ***-like intrusion:
>
> http://sioviz.ucsd.edu/~fialko/papers/fialkoGRL01b.pdf
>
> > Several questions.
> >> What is the lava at Socorro composed of?
> >
> > ***{If it has erupted in the past, there should be some hardened lava
> > on the surface that could be analyzed. But if it hasn't, which would be
> > my guess, then nobody knows. --MJ}***
> >
> > Why is this thing so
> >> big right in the middle of the continent (I understand that it is in
> >> a rift valley, but Jesus H. Christ, it is big for the location it is
in)?
> >
> > ***{The Earth sweeps up hundreds of thousands of tons of meteoric
> > material from space every day, plus unknown numbers of small comets (see
> > http://smallcomets.physics.uiowa.edu/). Result: the Earth is constantly
> > getting bigger, and as it does so, its surface gets flatter.
>
> Sorry to disagree, but the idea that the earth is getting bigger is not
> substantiated by any irrefutable evidence. Please don't tell me that you
are an
> earth expansion proponent. The amount of space debris that the earth
receives
> is miniscule compared to the radius of the earth. This has been proposed
before
> and soundly refuted. And any flattening of the earth is due mostly to
erosional
> forces.
>
> <snip>
>
> >> Is it possible that this could be the next flood basalt event (which
> >> is why I asked about the composition)?
> >
> > ***{It could be. The mid-oceanic ridges are mostly basalt that rose up
> > out of the same sorts of rifts. The Rio Grande rift, however, is not
> > underwater, and so any basalt that comes out of it will likely spread
> > over a very large area before it cools down enough to solidify. You
> > don't want to be there when that happens. :-) --MJ}***
>
> Considering the depth of this magma body, and the relatively slow rate of
> surface deformation, I find it unlikely that there will be an eruption any
time
> soon.
>
This magma body sits straddle of the Rio Grande Rift. To my knowledge there
is no true understanding of how "Rift Valleys operate. Having said that an
eruption from the Socorro Magma Body may not occur for century's, then again
it may erupt in this century.
Ralph Nesbitt

Quantcast