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Dormant Volcanoes Show Signs of Life, Satellite Reveals
Posted: April 14, 2002

Previously dormant volcanoes in two widely separated areas of the Pacific "ring of fire" are showing signs of life, as documented by new images taken by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (Aster) on NASA's Terra satellite.

Chiliques volcano in Chile
Geologists had previously considered Chiliques, a simple 5,778-meter (18,957-foot) stratovolcano with a 500-meter (1,640-foot)-diameter circular summit crater in northern Chile, to be dormant. However, a January 6, 2002 nighttime thermal infrared image from Aster found a hot spot in the summit crater, as well as several others along the upper flanks of the volcano's edifice, indicating new volcanic activity. Examination of an earlier nighttime thermal infrared image from May 24, 2000 showed no such hot spots. ...

Meanwhile, a couple of thousand miles to the northwest, a 10-by-20-kilometer (6.2- by-12.4-mile) section of ground near one of the long-dormant Three Sisters volcanoes in the Cascade Mountains of west-central Oregon has risen approximately 10 centimeters (3.94 inches) since 1996. According to the U.S. Geological Survey, this indicates the slow flow of magma or underground lava into the area. ...
Three Sisters volcanoes in Oregon.
The Three Sisters area -- which contains five volcanoes -- is only about 273.6 kilometers (170 miles) from Mount St. Helens, which erupted in 1980. Both are part of the Cascades Range, a line of 27 volcanoes stretching from British Columbia in Canada to northern California.