12/11/00

Mark Shwartz, News Service (650) 723-9296; e-mail: mshwartz@stanford.edu

The art and science of predicting volcanic eruptions

Volcanic eruptions and earthquakes are two of the most destructive forces on Earth.

But while scientists can do little more than guess when an earthquake will strike, tremendous strides have been made in forecasting deadly volcanic explosions.

In 1991, for example, volcanologists accurately predicted the eruption of Mount Pinatubo in the Philippines, enabling the safe evacuation of tens of thousands of residents.

The Pinatubo success came after an all-out emergency effort by Philippine and American scientists to closely monitor physical changes in and around the volcano. Today many volcanologists are looking forward to the creation of a permanent, worldwide volcano early-warning network.

That proposal and others will be the focus of a special panel on the future of volcanology to be held during the fall meeting of the American Geophysical Union (AGU) in San Francisco on Friday, Dec. 15, at 8:30 a.m.

A press conference will follow at 12:15 p.m.

Panelists from the United States, Iceland and Germany have been invited to the AGU session to discuss advances in technology and communication that could revolutionize the entire field of volcanology in the coming decade.

"It's not so much that we expect one technical breakthrough," says Stanford geophysicist Paul Segall, who will moderate the half-day AGU session.

"There's a confluence of a lot of things going on that should improve our ability to make predictions in the next 10 years," he notes.

Segall and Stanford colleague Howard A. Zebker, an associate professor of electrical engineering and geophysics, will discuss the increasingly popular use of spaceborne satellites to monitor volcanic activity on Earth.

Tiny movements on the surface of a volcano often indicate the build-up of magma below. Segall and Zebker speculate that, in the next decade, the Earth may be orbited by an array of specially equipped radar satellites capable of detecting millimeter-sized changes in the Earth's crust.

"Improved satellite coverage will make it possible to collect these data over all of Earth's 600 potentially active volcanoes weekly or even daily," they predict, allowing researchers to forecast volcanic events "to a much greater degree than is currently possible."

Segall points out that earthquakes often foreshadow major volcanic events.

"You can't move lots of magma through the Earth's crust without earthquakes," he says, noting that volcanologists have developed specialized seismic arrays for imaging volcanic systems.

Panelist Bernard Chouet of the U.S. Geological Survey will describe some of the latest advances in volcano seismology, including portable broadband seismic instrumentation; high-resolution tomography to create images of underground volcanic structure; and other tools to measure the acoustic properties of magma and hydrothermal fluids.

Several researchers will discuss the use of the global positioning system (GPS) to detect bulging of the ground, as well as geochemical devices to monitor sudden changes in atmospheric gas chemistry that often precede eruptions.

Andrew J. L. Harris and his colleagues from the University of Hawaii will describe their pioneering thermal monitoring system that records second-by-second temperature changes at Hawaii's Pu'u O'o volcano, then instantly transmits the data to a computer via satellite.

"We advocate that such remote systems should be installed on other volcanoes by 2010 in order to better monitor ongoing eruptions," say Harris and his co-workers.

Scientists from NASA's Jet Propulsion Laboratory will demonstrate the use of digital animation to illustrate potential volcanic hazards, and researchers from Los Alamos National Laboratory and the Pacific Disaster Center will discuss ways to improve volcanic risk assessment.

"Much work remains to be done toward a synthesis of seismological, geochemical and petrological observations into an integrated model of volcanic behavior," Chouet concludes.

Segall agrees and is optimistic about volcanology's future.

"Unlike earthquake prediction," he says, "we can actually do something about volcanoes."

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By Mark Shwartz
 

Photographs of erupting volcanoes are available on the Web at http://newsphotos.stanford.edu (slug: "AGU Volcano.jpg").