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<DIV><FONT color=#000000><FONT color=#000000><SPAN
class=707533414-03032006><FONT face=Arial size=2>The Nature article that we have
been hearing about is titled "Uplift, thermal unrest and magma intrusion at
Yellowstone caldera" by Charles W. Wick, Wayne Thatcher, Daniel Dzurisin and
Jerry Svarc and appears in Vol 440 No 2, 2 March 2006 issue of Nature on pages
72-75</FONT></SPAN></FONT></FONT></DIV>
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<DIV><FONT color=#000000><FONT color=#000000><SPAN
class=707533414-03032006><FONT face=Arial size=2>The cover of this issue of
Nature has a picture of Steamboat in steam phase with the catchy title "ECHO
FROM A SUPERVOLCANO Uplift has a downside in Yellowstone Park". As
with most catchy titles, it really doesn't have much to do with the article, but
it makes you want to read it.</FONT></SPAN></FONT></FONT></DIV>
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<DIV><FONT color=#000000><FONT color=#000000><SPAN
class=707533414-03032006><FONT face=Arial size=2>Most of the article deals with
the movements that have been seen in the surface and hypotheses about what
is causing the movement (i.e. details of magma flux). I'm not a geologist,
so I won't try to go into those details, but will just mention some things that
caught my attention in relation to geysers. I'll be summarizing my
understanding of what they are saying, so if someone notices I messed up, please
correct what I have said. Everything I mention occurs in the
last three paragraphs of the
article.</FONT></SPAN></FONT></FONT></DIV>
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<DIV><FONT color=#000000><FONT color=#000000><SPAN
class=707533414-03032006><FONT face=Arial size=2>The
authors suggest that uplift causes changes in the
permeability and increasing permeability in geyser conduits may
increase geyser eruption frequency. (They cite Ingebritsen &
Rojastaczer "Controls on geyser periodicity" Science, 262, 889-892,
1993.)</FONT></SPAN></FONT></FONT></DIV>
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<DIV><FONT color=#000000><FONT color=#000000><SPAN
class=707533414-03032006><FONT face=Arial size=2>They mention the response of
geysers to earthquakes... In Husen, Taylor, Smith, & Heasler "Changes
in geyser eruption behavior and remotely triggered seismicity in Yellowstone
National Park produced by the 2002 M 7.9 Denali fault earthquake, Alaska"
Geology 32, 2004. (Yes, "Taylor" is Ralph Taylor) an increase in
geyser activity was noted after the Denali earthquake produced ~0.5
microstrain of dynamic strain. The authors of this latest
paper calculate that the strain caused by the observed inflation is an
order of magnitude greater (>6 microstrain) but this strain is applied over
3-4 years. They think this could have led to some of the surface
manifestations ("accentuated thermal unrest" in NGB in 2000-2003 and near
Nymph Lake).</FONT></SPAN></FONT></FONT></DIV>
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<DIV><FONT color=#000000><FONT face=Arial color=#000000 size=2><SPAN
class=707533414-03032006>Also of note, the authors make quite clear that thermal
disturbances in NGB are fairly common and that even the stronger
disturbance that they looked at was not unique. What is different is
that deformation was actually measured during the disturbance mentioned in the
article and a cause-and-effect relationship between the deformation
and the disturbance is suggested. They further suggest that
deformation may have caused past disturbances but the deformation
would have been undetected.</SPAN></FONT></FONT></DIV>
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<DIV><SPAN class=707533414-03032006><FONT face=Arial color=#000000 size=2>Vicki
Whitledge</FONT></SPAN></DIV></FONT></FONT></BODY></HTML>