Reply #37: I would worry more about Mount Rainier

[IndianaGreen]

the long overdue eruption there would truly be catastrophic!

Here is some data from Yellowstone:

This is from an official US Government website that is available to the public. The information is in the public domain

TEMPORARY HYDROTHERMAL MONITORING PROGRAM TO BEGIN AT NORRIS GEYSER BASIN: 8 August 2003

In response to notably increased heat and steam emissions in parts of Norris Geyser Basin, the Yellowstone Volcano Observatory will deploy a temporary network of seismographs, Global Positioning System (GPS) receivers, and temperature loggers. The temporal deployment is intended to document chemical and physical signals that accompany this increased activity, to identify the underground locations of hydrothermal steam sources and the relationship of the Norris geyser basin to the background general seismicity, and crustal deformation of the Yellowstone caldera. It may also detect any precursory signals to geyser eruptions and hydrothermal explosions.

The GPS equipment is designed to detect very small movements of the earth, and the seismic array can measure earthquakes associated with flow of thermal water and earthquakes located on buried faults. Seven seismometers, that record a wide range of seismic frequencies typical of hydrothermal and volcanic systems, called broadbands, will be placed throughout the Norris Geyser Basin, five of them within and around the hydrothermal disturbed area itself. These "broadband" seismometers are especially sensitive to the long-wavelength ground vibrations that occur as water and gas move through underground cracks as well as deeper volcanic sources.

The seismic array will be complimented by high precision GPS receivers that precisely measure the coordinates of points on the ground from data transmitted by an array of satellites that can be compared with each other to measure the relative ground velocities through time. These data compliment Yellowstone’s permanent GPS network.

Movements of the ground associated with underground pulses of water and steam (including geyser eruptions) may be detected by this new technology. Thermometers placed in hot springs and creeks will continuously document the flow of water out of the geyser basin. The scientists hope to link individual pulses of water, changes in their chemistry and temperatures to pressures in the earth. This information may provide information on ground motions and seismic signals that precede them.

The Norris Back Basin has been closed since July 23, 2003, after formation of new mud pots, changes in geyser activity, and significantly increased ground temperatures (up to 200 degrees Fahrenheit) in some areas near the Back Basin trail. Additional observations include vegetation dying due to thermal activity and the changing of several geysers' eruption intervals. The heightened rate of steam discharge has continued to the present time.

The Yellowstone Volcano Observatory (YVO) is a collaborative partnership between the U.S. Geological Survey, the University of Utah and Yellowstone National Park. The Yellowstone seismic and GPS network consists of a modern digitally telemetered network of 22 seismographs and 5 permanent GPS receivers throughout Yellowstone National Park in support of the YVO and an NSF project focused on the Yellowstone hotspot. These networks are operated and recorded by the University of Utah.

The Yellowstone Volcano Observatory is designed to provide geophysical and geochemical monitoring of Yellowstone National Park that enables timely guidance to the NPS and improves scientists understanding of ongoing volcanic, hydrothermal and earthquakes activity. Two NSF-supported University research consortiums and the University of Utah are providing the temporary equipment and technical support (IRIS, Integrated Research Institutes in Seismology and UNAVCO, University NAVSTAR Consortium). Funding is available primarily from the USGS Volcano Hazards Program and Yellowstone National Park.


Closure of the western part of the Back Basin Trail within the Norris Geyser Basin

Press Release http://www.nps.gov/yell/press/0362.htm

On July 22, Yellowstone National Park issued a press release to inform the public that it would close the western part of the Back Basin Trail within the Norris Geyser Basin. This follows increased thermal output within this area including areas immediately adjacent to the trail, beginning on July 11. Norris is the hottest and most seismically active geyser basin in Yellowstone. Recent activity in the Norris Geyser Basin has included formation of new mud pots, an eruption of Porkchop Geyser (dormant since 1989), the draining of several geysers, creating steam vents and significantly increased measured ground temperatures (up to 200 degrees Fahrenheit). Additional observations include vegetation dying due to thermal activity and the changing of several geysers' eruption intervals. Vixen Geyser has become more frequent and Echinus Geyser has become more regular.

Much of this activity may be attributed to the "annual disturbance", which, as implied by its name, is an annual event at Norris with increased boiling, increased turbidity of thermal pools, and apparent increased injection of waters from deeper parts of the hydrothermal system. The
disturbance occurs within the summer season. A study of changes during the 1995 annual disturbance was published by Fournier et al. (2002)<http://geopubs.wr.usgs.gov/open-file/of02-344/>. This year, changes at Norris are more pronounced than in previous years.

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July 2003 Yellowstone Seismicity Summary

During the month of July 2003, 37 earthquakes were
located in the Yellowstone region. The largest shock to
occur during this report period was a magnitude 2.0
earthquake on July 4th at 06:22 UTC, located about
6 miles west northwest of Norris Junction, Wyoming.

Earthquake activity in the Yellowstone region is at
background levels.

http://vulcan.wr.usgs.gov/Vhp/framework.html