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The Earth's crust, on which we live and depend, is in large part the product of
millions of once-active volcanoes and tremendous volumes of
magma
that did not erupt but instead cooled below the surface. Such
persistent and widespread volcanism has resulted in many valuable natural
resources throughout the world. ...
Groundwater heated by
large, still-hot magma bodies can be tapped for geothermal energy.
-- Excerpt from:
Brantley, 1994, Volcanoes of the United States, USGS General
Interest Publication
The internal heat associated with young volcanic systems
has been harnessed to produce geothermal energy.
For example, the electrical energy generated from
The Geysers geothermal field in northern California can
meet the present power consumption of the city of San Francisco.
-- Excerpt from: Tilling, 1985, Volcanoes:
USGS General Interest Publication
Geothermal energy can be harnessed from the Earth's natural heat
associated with active volcanoes or geologically young
inactive volcanoes still giving off heat at depth.
Steam from high-temperature geothermal fluids can be used to drive
turbines and generate electrical power, while lower
temperature fluids provide hot water for space-heating purposes, heat
for greenhouses and industrial uses, and hot or
warm springs at resort spas. For example, geothermal heat warms more
than 70 percent of the homes in Iceland,
and The Geysers geothermal field near Santa Rosa, in Northern California
produces enough electricity to meet the power demands of San Francisco.
The Geysers area is the largest geothermal development in the world.
In addition to being an energy resource, some geothermal waters
also contain sulfur, gold, silver, and mercury that
can be recovered as a byproduct of energy production.
-- Excerpt from: Kious and Tilling, 1996, This Dynamic Earth: The Story of Plate
Tectonics: USGS General Interest Publication
In recent years, volcanic energy has been harnessed by a geothermal power plant
on Kilauea's east rift zone; the three megawatts of electricity produced are fed
into the grid of the local utility company. Much larger capacity geothermal
development is under discussion.
-- Excerpt from: Tilling, Heliker, and Wright, 1987,
Eruptions of Hawaiian Volcanoes:
Past, Present, and Future: USGS General Interest Publication
Geologically young volcanoes found in our area
suggest that central Oregon
may contain some of the best prospects for
geothermal exploration in the continental United States.
One study done at
Newberry Volcano
estimated the energy
potential to be up to 13,000 megawatts.
Another study by Bonneville Power Administration estimates a 16,000 megawatt
potential.
-- Information courtesy USFS, Deschutes National Forest Website, 2000
The Geysers geothermal field near Santa Rosa, in Northern California
produces enough electricity to meet the power demands of San Francisco.
The Geysers area is the largest geothermal development in the world.
-- Excerpt from: Kious and Tilling, 1996, This Dynamic Earth: The Story of Plate
Tectonics: USGS General Interest Publication
Gravity and teleseismic studies suggest that a large silicic magma
chamber, approximately 14 kilometers in diameter, lies 7 kilometers and
deeper beneath the
(Clear Lake) volcanic field.
This reservoir is
thought to be the heat source for the Geysers geothermal field
(on the southwest side of the volcanic field),
which is the largest producing geothermal field in the world,
with installed electrical generating capacity of around 2,000 megawatts in 1988,
enough electricity for about two cities the size of San Francisco.
-- Excerpt from:
Wood and Kienle, 1990, Volcanoes of North America: United States and Canada:
Cambridge University Press, 354p., p.226-229,
Contribution by Julie M. Donnelly-Nolan
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Casa Diablo, Long Valley Caldera, California
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Wells drilled at Casa Diablo, on the southwest side of Long Valley's
resurgent dome,
tap into the caldera's hydrothermal system
by pumping hot water at temperatures near 170 degrees C to supply three
geothermal power plants that generate about 40 megawatts of electricity. Cooled
geothermal water from the plants is injected back underground.
-- Courtesy of:
U. S. Geological Survey's
Long Valley Monitoring Project - Hydrologic Studies, 1997
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Salton Sea Geothermal Field, California
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The
Salton Buttes
lie within the Salton Sea geothermal field,
where temperatures at 1.5 to 2.5 kilometers reach 360 degrees C, and sediments
of the Colorado River delta are begin metamorphosed to greenschist facies.
-- Excerpt from:
Wood and Kienle, 1990, Volcanoes of North America: United States and Canada:
Cambridge University Press, 354p., p.245,
Contribution by: L. J. Patrick Muffler
The Salton Sea geothermal field lies in the Salton Trough,
the landward extension of the Gulf of California, an area of
active crustal spreading.
The Salton Buttes volcanoes lie within the
Salton Sea geothermal field
where temperatures measured in wells drilled for geothermal brines range up to
360 degrees C at depths of 1,500 to 2,500 meters (Helgeson, 1968). The wells
produce a hot brine containing up to 160,000 ppm of dissolved solids, chiefly Cl,
Na, K, Ca, and Fe (White, 1968). Under the influence of this hot saline brine,
the sediments of the Salton Trough are being transformed into metamorphic rocks
of the greenschist facies (Muffler and White, 1969).
-- Excerpt from:
Robinson, Elders, and Muffler, 1976, Quaternary volcanism in the Salton Sea
geothermal field, Imperial Valley, California:
GSA Bulletin 87, p.347-360, March 1976
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