Re: Super Volcano Will Challenge Civilization, Geologists Warn

From: George (george_at_wtfiswrongwithyou.com)
Date: 03/11/05 

Date: Fri, 11 Mar 2005 04:45:24 GMT

"Ralph Nesbitt" <ralph-nesbitt@sbcglobal.net> wrote in message
news:l_7Yd.4866$yp.687@newssvr11.news.prodigy.com...
>
> "George" <george@wtfiswrongwithyou.com> wrote in message
> news:Bo2Yd.114354$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
>

Here are some links that descrbe the Rio Grande Rift:

http://home.att.net/~sgeoveatch/rio_grande_rift.htm

http://tapestry.usgs.gov/features/28riogrande.html

http://academic.emporia.edu/aberjame/struc_geo/rio/rio.htm

http://www.clas.ufl.edu/users/pciesiel/gly3150/rio_grande_rift.html

http://www.ees.nmt.edu/Geop/Ristra/ristra.html

Quantcast