Mapping Volcanic Menaces

PITTSBURGH—Each day, planes en route between North America and Asia carry more than 10,000 people and $1 million worth of cargo over the active volcanoes of the Aleutian Arc. Clouds of ash can wreak havoc on the engines of these airplanes, which fly in one of the world's busiest air-trade routes.

Many Aleutian Arc volcanoes, because of their remoteness and volatility, have been challenging for volcanologists to study. Without access to the volcanoes, scientists have had trouble predicting the volcanoes' behavior.

University of Pittsburgh Assistant Professor Michael Ramsey's research has confirmed that detailed information about remote volcanoes now can be accessed from space, based on infrared mapping by satellite. Ramsey, director of Pitt's Image Visualization and Infrared Spectroscopy laboratory in the Department of Geology and Planetary Sciences, presented his findings at the December meeting of the American Geophysical Union.

Volcanologists predict the behavior of volcanoes by analyzing the mineral composition of rock. Until now, researchers worked from the ground, taking samples from the volcanoes themselves. But Ramsey used the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), an imaging instrument aboard NASA's satellite Terra, to examine rock composition.

ASTER combines three imaging technologies—visible/near infrared, short-wave infrared, and thermal infrared—to obtain high resolution maps of land surface temperature, emissivity, reflectance, and elevation. Ramsey matched ASTER images with samples of rock from a volcano in the Aleutian Arc, confirming the images' accuracy.

"With ASTER, we can observe changes weekly," said Ramsey. "This is very important after the initial eruption and the formation of a lava dome. These act like corks in many ways, and subtle changes in their temperature, composition, or texture reveal information about potential eruptions."

Ramsey and researchers from the University of Alaska Fairbanks and the Alaska Volcano Observatory did their research at Black Peak, an inactive volcano on the Alaskan Peninsula that had never been visited. Using satellite images and global positioning systems to locate two areas with differing rock compositions, they traveled to the regions by helicopter and took rock samples. The composition of the rock samples matched the predicted composition of the satellite images, which had been imaged in blocks of 90 square meters.

Because of the success of this research, Ramsey recently was appointed a full member of the ASTER science team and received a $600,000 grant from NASA to help automate communication between existing volcano monitoring systems. Currently, weather satellites that monitor Aleutian Arc volcanoes are operated by the Alaska Volcano Observatory and ASTER is controlled by NASA. If the two are programmed to work together, emergency data can be taken more efficiently and could improve preparations for disasters.

"We are hoping to have the satellites talk to one another and cut out a lot of the time spent on human interaction," said Ramsey. "This project also looks to expand beyond volcanoes in Alaska to other areas and other natural disasters around the world."

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