Ash Plume from Ambrym Volcano, Vanatu. Also in the South Pacific Ocean, the Ambyrm Volcano, originally captured in an image taken on April 27, continued to erupt in mid-May 2004. This image was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite on May 15. Vanuatu Island is pictured at the top left of the image, and a plume of volcanic ash is drifting southeastward from Ambrym, which is near the island’s center. MODIS detected a thermal signature (marked in red) in addition to the ash plume.
Ambrym is a large basaltic volcano with a 12-km-wide caldera, and one of the most active volcanoes of the New Hebrides volcanic arc.
The caldera is the result of a huge Plinian eruption, which took place around 50 AD. Its explosive force is rated 6, the third highest in the Smithsonian Institution’s Volcanic Explosivity Index ranks of the largest volcanic explosions in recent geological history.
While at higher elevations cinder cones predominate, the western tip of the island is characterized by a series of basaltic tuff rings, of which the largest is about 1 kilometre (0.62 mi) in diameter. These were produced by phreatic eruptions when magma contacted the water table and water-saturated sediments along the coast. Ash Plume from Ambrym Volcano, Vanatu.
Credit: Jeff Schmaltz, MODIS Rapid Response Team, NASA/GSFC