News Release

Scientist To Discuss Developing Volcano At UNC-CH Geologic Symposium

Meeting Announcement

University of North Carolina at Chapel Hill

By BRET JOHNSON
UNC-CH News Services

CHAPEL HILL -- Scientists have determined that magma beneath a volcano north of Los Angeles has risen two and a half miles closer to the surface, increasing the likelihood of a catastrophic eruption in the geologically near future.

The site of the volcano, the Coso Geothermal Field in southern California, will be discussed at the Fourth Annual Coso/Indian Wells Valley Technical Symposium, Nov. 18 and 19 at the University of North Carolina at Chapel Hill William and Ida Friday Center for Continuing Education.

The geothermal field, situated 130 miles north of Los Angeles, is valuable for its ability to produce steam which is turned into cheap, clean electrical power. Roughly 250 megawatts of electricity, enough to power over 60,000 homes, is fed into the southern California power grid.

The Coso hot springs caught the attention of Hollywood's elite who used it as a vacation site in the late 1920s and 1930s. The Navy established a weapons station at China Lake, an area including Coso, in 1943 to develop new bombs, missiles and radar systems.

Teamed with the U.S. Geological Survey, the Navy explored Coso"s potential as an energy source in the 1970s. A private corporation was hired to build the geothermal plants there in the mid-1980s.

Drs. Allen Glazner, Jonathan Miller and Curtis Manley of UNC-CH are involved in researching the geothermal field and its history. Their work is funded in part by a portion of the Navy's profits from Coso.

The scientists use samples of prehistoric lava domes to investigate changes within the magmatic system. Studying the composition of mineral crystals that grew in the lava, Drs. Manley and Charles Bacon of the U.S. Geologic Survey have determined the temperature in the magma chamber and the depth beneath the Earth's surface to the top of the chamber.

The two were able to determine for the first time how quickly a magma chamber can rise toward the surface.

"We're lucky because we have just the right minerals in the lava domes, and all the domes are accessible -- nothing has been buried or lost -- so we have the whole history to look at," said Manley. "Once we learn how to read them, the lava domes are like progress reports from the magma chamber."

The magma chamber at Coso is steadily rising half an inch per year.

"The closer a magma chamber approaches the Earth's surface, the greater the likelihood of a major, even cataclysmic eruption," said Manley. "At Coso, a major eruption is unlikely for tens of thousands of years, but a small eruption could happen at any time."

Manley says that over the last 300,000 years, the magma chamber has warmed slightly, from about 1,365 to 1,420 degrees Fahrenheit and the chamber has risen from six miles beneath the surface to three and a half.

Manley and Bacons' work is also supported by data obtained by Miller in the UNC Isotope Geochemistry Lab. His analyses indicate that as the chamber has risen, increasing amounts of the crust have melted and mixed into the magma.

The Nov. 18-19 symposium will host 20 researchers from UNC-CH, the Navy and other universities.

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Note: Manley can be reached at (919) 962-0692 or 962-0694.
Contact: David Williamson


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