On Oct. 26, 2010, Merapi volcano in Indonesia erupted, killing more than 150 people to date and prompting authorities to evacuate tens of thousands of inhabitants from around the mountain. On Nov. 8, 2010, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft captured an image of the hot volcanic flows that resulted from continued collapse of the summit lava dome, and the ensuing release of ash plumes. In this daytime image, vegetation is displayed in red, and older volcanic flows are in blue-gray just visible under the edge of the clouds. The hot volcanic flows were detected by the thermal infrared bands, and they are displayed in yellow. Merapi's summit position is indicated by the blue star. To the west of the summit, ash and water vapor clouds are visible in the eruption plume. The ASTER image is located at 7.5 degrees south latitude, 110.5 degrees east longitude. The image covers an area of 33 by 40 kilometers (20 by 25 miles).
With its 14 spectral bands from the visible to the thermal infrared wavelength region and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet. ASTER is one of five Earth-observing instruments launched Dec. 18, 1999, on Terra. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and data products.
The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.
The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate, Washington, D.C.
More information about ASTER is available at http://asterweb.jpl.nasa.gov/.