Two volcanic plumes from Mt. Etna composed of different materials are visible
in new images from NASA’s Multi-angle Imaging SpectroRadiometer on the Terra
satellite. A bright, brownish plume drifting southeast over the Ionian Sea is made up
primarily of volcanic ash — tiny frozen fragments of lava. A fainter, bluish-white plume,
seen near the summit, contains very fine droplets of water and dilute sulfuric acid.
The images, taken July 22, 2001, are available at

The Multi-angle Imaging SpectroRadiometer, built and managed by NASA’s Jet
Propulsion Laboratory, Pasadena, Calif., is one of several Earth-observing experiments
aboard Terra, launched in December 1999. The instrument acquires images of the Earth
at nine angles simultaneously, using nine separate cameras pointed forward, downward,
and backward along its flight path. More information is available at .

JPL is a division of the California Institute of Technology in Pasadena.