After more than a decade of inactivity, Mount St. Helens rumbled back to life in September 2004. An ongoing series of tremors within the volcano coupled with upward movement of magma toward its caldera prompted geologists to issue a Level 3 alert, stating that Mount St. Helens could experience a moderately severe eruption at any time.
In order to help geologists and vulcanologists assess the nature and magnitude of the risk, on September 24, 2004, NASA flew a low-altitude aircraft carrying the MODIS/ASTER Airborne Simulator (MASTER) directly over the volcano to obtain high-resolution images of its caldera. The images above show the caldera in spectacular detail; the high-resolution copies also available above have a spatial resolution of 3 meters per pixel. The top image shows Mount St. Helens in natural color while the bottom scene was produced using MASTER’s thermal infrared detectors. The red-orange patches in the center of the volcano’s caldera show the location of the lava dome. These red-orange patches are produced by the tremendous heat that is venting from the lava dome.
After the image was obtained, Mount St. Helens has emitted several plumes of ash and steam, as if to validate geologists’ warning that it could erupt at any time.
NASA images courtesy Jeff Myers and Rose Dominguez, MASTER Project, Ames Research Center and the Jet Propulsion Laboratory
- Aircraft Sensors - MAS