Michael F. Sheridan, professor and chair of the Department of Geology who holds the largest grant in the U.S. to study volcanic mudslides, says scientists have much to learn from the tragedies in Nicaragua and Honduras so that other populations do not suffer the same terrible fate.

"The mudflow in Nicaragua is the worst volcanic disaster of this decade," said Sheridan.

On Oct. 29, he presented research at the Geological Society of America annual meeting in Toronto that described how computers are being used to interpret satellite data to predict the likely sources, sizes and paths of volcanic mudflows so that populations at risk can be informed and safely evacuated.

Using a mathematical model, the research also projected the potential devastation that would occur in a key industrial town near Colima volcano in Mexico if extremely fast-moving volcanic mudflows are unleashed when the volcano reaches the climactic stage of its eruption cycle, which is expected during the next decade. The largest mudflow the researchers calculated from Colima would involve a wall of water and debris 200 feet high.

"We have an ideal research program to incorporate data from Casita volcano with our findings on Mexican volcanoes so that we can understand better what causes these huge mudflows," he said.

In Sheridan's estimation, mudflows are the volcanic phenomena posing the greatest danger to populations. In 1985, a volcanic mudslide in Colombia killed 26,000 people.

"My goal in going to Casita volcano is to find out what triggered this catastrophic collapse of the volcano," he said.

Initial reports from Nicaragua have indicated that it was Hurricane Mitch that caused the terrible mudflows on Casita volcano, but Sheridan noted that other possible contributing factors, including the decompression of a geothermal system on Casita, cannot be ruled out.

"And last week, Cerro Negro, an adjacent volcano, has also begun to erupt," he said. "We need to explore the connection with this adjacent erupting volcano."

Sheridan plans to do fieldwork on Casita, checking to see if the material that came out of Casita was hot, which would mean that a geothermal system was involved.

"This is a unique opportunity to study a major collapse of a volcano before the evidence is removed or changed by geologic agents," said Sheridan.

After gathering the field data, Sheridan plans to use remotely sensed data to test his assumption that satellite information can provide a kind of "geologic X-ray" to identify soft spots at the surface of a volcano, particularly those areas that are susceptible to a catastrophic collapse.

Funding for Sheridan's expedition comes from the National Science Foundation.