The Soufriere Hills Volcano on the Caribbean island of Montserrat continued releasing ash and steam in mid-December 2008. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured this image of the area on December 13, 2008. In this image a plume blows away from the volcano over the Caribbean Sea. Moving in a counter-clockwise direction, the plume forms a flattened arc that extends hundreds of kilometers westward, well past the island of San Juan.
According to the Montserrat Volcano Observatory, Soufriere Hills released sulfur dioxide between December 5 and December 12. When sulfur dioxide and other volcanic gases mix with water and oxygen in the presence of sunlight, the result is volcanic smog, or vog. Besides volcanic ash emanating from Soufriere Hills, the plume in this image may also contain vog.
Soufriere Hills is a stratovolcano composed of alternating layers of hardened lava, solidified ash, and rocks ejected by previous eruptions. In 1995, a series of major eruptions from this volcano eventually destroyed the island’s capital city, Plymouth. Prior to that event, a seventeenth-century eruption was the only historical eruption recorded from this volcano. The volcano experienced an explosive eruption in early December 2008, and it released plumes steadily after that event.