Spotlight's on UB volcanologists as fiery disasters erupt on TV and movie screens

This month, nature's masters of pyrotechnics are coming into your living room and to a theater near you. If 1996 was dominated by a "Twister," 1997 has three volcanic nightmares in store for you.

"Dante's Peak," a film that promoters promise will "take you deep into the heart of nature's most devastating spectacle" opens in theaters this Friday.

And on Feb. 23 at 8 p.m., ABC will broadcast a news program about the fiery natural phenomena called "The World's Most Dangerous Volcanoes." The show will be followed by a made-for-TV movie, "Volcano: Fire on the Mountain" about a beautiful ski resort that is about to be blown to bits by a long-dormant volcano. A third movie will open later this year.

When the producers of the news program needed an expert on some of the most powerful volcanoes, they interviewed Michael F. Sheridan, professor and chair of geology.

Sheridan has made a career out of mapping the predicted direction of flows from volcanic eruptions before they occur, based on extensive fieldwork and knowledge of the historic patterns of a particular volcano.

Most recently, he has developed three-dimensional computer simulations that predict how far and how fast those dangerous flows will travel, helping public- safety officials to determine ahead of time which areas to evacuate.

Sheridan appears on the ABC special discussing aspects of his work on Popocatepetl, just 40 kilometers from Mexico City and one of the largest volcanoes in the world. That volcano has demonstrated variations in activity since the end of 1994.

But trying to predict how and when a volcano will erupt is a tricky business and predictions of catastrophic eruptions, especially those near large population centers, must be made with extreme caution.

For that reason, volcanologists like Sheridan and his colleague Marcus Bursik, associate professor of geology, are trying to uncover as many secrets of these powerful, subterranean phenomena as they can.

Volcanologists stress that all aspects of volcanoes, from the forces that cause the plumes to eject so violently to the chemical composition of the tiny particles that are liberated by eruptions, are all critical pieces in the puzzle.

"Right now, the main focus of my research is on big eruptions that produce hot, pyroclastic flows that travel up to 60 miles away from a volcano," said Bursik. "We are trying to explore how these flows travel so far."

He also is attempting to discover why some of these flows jump very high ridges, up to 3,000 feet high at distances of 40 miles from the volcano.

To find out, he and his colleagues are exploring new methods of examining volcanic plumes. He has authored a new book on the subject, to be published in April.

To find out how fast the lava dome on top of Long Valley Caldera in California may be expanding, Bursik has been using data obtained by Global Positioning Satellites network. Changes in rates of expansion may provide scientists with clues about impending eruptions.

Other data may provide scientists with information about what happens underground just prior to an eruption.

In a paper published in Nature, Bursik described how he and a colleague at the California Institute of Technology modeled the eruption process.

The results demonstrated that a conventional theory about how eruptions occur could be incorrect.

That theory described eruptions as resulting from processes similar to those that expel champagne corks from their bottles: namely that magma charged with dissolved gases bubbles out of solution, shooting the magma out of the volcano.

Bursik and his colleague simulated an eruption, using a 20-inch tube filled with glass beads and the liquid refrigerant Freon, which they spun in a centrifuge and then subjected to a sudden reduction in pressure.

According to Bursik, "a wave of depressurization" then moved across the tube, vaporizing the Freon and ejecting the glass beads, pointing to a new explosive vaporization process in eruptions.

For people who don't live near volcanoes, such investigations may not be of much concern.

But researchers are discovering that in fact, no matter where you live, you will be affected by volcanoes. The Mt. Pinatubo eruption of 1991, for example, has been mentioned as a possible cause behind the disruption in global weather patterns in the years just following the eruption.

In search of information on the particles emitted from volcanoes, Sheridan and Bursik have visited Kamchatka, a remote region in eastern Siberia, and home to 30 active volcanoes.

According to Sheridan, it is possible that volcanic emissions, as well as other natural sources of gases, may have a major ecological effect on the atmosphere, such as expanding the hole in the ozone layer. Measurements of volcanic compounds therefore could have important implications for the modeling of global change.

Another area of Bursik's research will get the attention of frequent flyers: volcanic plumes or ash clouds can pose serious problems for airplane engines.

"Particles that have been ejected into the atmosphere from explosive volcanoes get into jet engines, temporarily causing them to 'flame out' or stall," said Bursik.

He gave an example of a KLM jet that in 1989 flew into a volcanic plume produced by an eruption of the Redoubt Volcano in Alaska. Its engines stalled and the jet fell through the ash cloud from its cruising altitude of 25,000 feet to about 14,000 feet before the pilot was able to restart the engines.

Other near-disasters because of ash clouds have occurred, including several during the 1991 eruption of Mt. Pinatubo.

And you don't have to be directly overhead a volcano to be affected by the ash it sends into the atmosphere. In 1992, an ash cloud from the eruption of the Spurr volcano in Alaska drifted over Cleveland airspace forcing airplanes to fly around it.

Bursik and his colleagues are developing ways to calculate how much ash may be found in different areas of a particular cloud, so that they can then see how dangerous it is.

He is developing a mathematical model that could predict for airplanes how much of the ash they might encounter, given a particular flight route.

Whether they fly or not, students also benefit from this wealth of volcanological expertise.

Bursik and Sheridan, along with Dennis S. Hodge, professor of geology, developed a fully interactive computer program that brings volcanoes to life for students in two UB undergraduate courses: "The Earth" and "Environmental Earth Sciences."

Unlike other programs that have mostly point-and-click features, this one shows how changing a specific variable, such as the viscosity of a lava flow, can alter the speed or outcome of a geological event.