Geologic "X-Rays" Pinpoint Weak Spots On Volcano Surface

TORONTO -- By analyzing data collected by satellites circling the globe, volcanologists at the University at Buffalo have produced geologic "X-rays" that can pinpoint potentially dangerous weak spots on the surface of a volcano.

They reported here today (Oct. 29, 1998) at the annual meeting of the Geologic Society of America that they have used such data to produce a volcanic-hazards map for Citlalpetl, an active volcano about 80 miles west of Vera Cruz, Mexico.

Much the way an X-ray allows a physician to view a patient's bones and internal organs, hyperspectral data collected by satellites has allowed Michael Sheridan, Ph.D., chair and professor of the UB Department of Geology, and UB graduate student Bernard Hubbard to remotely "see" what's happening to minerals beneath the volcano's surface.

The hyperspectral data can be interpreted to determine properties such as the presence of water or iron-bearing minerals and clay on the volcanic surface, all of which can contribute to a weakening of the volcanic structure.

"We get back enormous amounts of data that provide us with something like the fingerprint of a volcanic surface," Sheridan explained.

Their preliminary results on Citlalpetl confirm their hypothesis that large amounts of certain materials on a volcano's surface represent soft spots that could easily trigger avalanches.

This is the first time that remote detection of these materials has been used in cooperation with public-safety officials to develop a volcanic-hazards map.

"We know how to estimate where avalanches end," said Sheridan. "This analysis can help us determine where they start."

In combination with fieldwork, such data will help the UB researchers develop a probability curve of the frequency for different catastrophic events resulting from volcanoes, such as landslides and avalanches, that could be used for hazard mitigation by public officials.

The project is funded by a $300,000 grant from the National Aeronautics and Space Administration.