| Subj: | tremors |
| Date: | 12/1/00 11:57:46 AM Pacific Standard Time |
| From: ANON.navy.mil (ANON
PSNS) To: bardsquill@aol.com ('bardsquill@aol.com') |
|
hi Kent...
thanks for getting the message out...
it appears that Yellowstone Caldera experienced another...for lack of
a
better term..."harmonic tremor" type seismic event at about 0722 MST on
the
1st of December...
somewhat before...and...since that episode...low level "harmonic
tremors"
continue...
here is an interesting technical paper regarding recent subsidence
and
uplift episodes...
Migration of Fluids Beneath Yellowstone Caldera Inferred from
Satellite
Radar
Interferometry...
http://quake.wr.usgs.gov/study/deformation/YELL_1998/Yellowstone98.html
Satellite interferometric synthetic aperture radar is uniquely suited
to
monitoring year-to-year deformation of the entire Yellowstone caldera
(about
3000 square kilometers). Sequential interferograms indicate that
subsidence
within the caldera migrated from one resurgent dome to the other
between
August 1992 and August 1995. Between August 1995 and September 1996
the
caldera region near the northeast dome began to inflate, and
accompanying
surface uplift migrated to the southwest dome between September 1996
and
June 1997. These deformation data are consistent with hydrothermal
or
magmatic fluid migration into and out of two sill-like bodies that are
about
8 km directly beneath the caldera.
Sour Creek (SC) dome...northeastern quadrant of Yellowstone
Caldera...
August 1992 to June 1993...over 30 mm of inferred subsidence...
August 1995 to September 1996...main deformation mode is uplift (~20
mm)...
Mallard Lake (ML) dome...southwestern quadrant of Yellowstone
Caldera...
June 1993 to August 1995...over 40 mm of subsidence...
July 1995 to June 1997...over 30 mm of uplift...
see this url for an uncluttered location map of the SC & ML
domes...
http://ibis.grdl.noaa.gov/SAT/at/yellowstone.html
here are the urls for the latest
seismograms...
http://www.seis.utah.edu/helicorder/ut.YFT_EHZ_WY.2000120100.gif
http://www.seis.utah.edu/helicorder/ut.YNR_EHZ_WY.2000120100.gif
regards...
