Mount Pagan—the northeastern member of a pair of volcanoes comprising a small Pacific island—released a plume of ash and steam on April 15, 2009. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this image the same day. The volcano released a faint plume that blew toward the northwest over the Pacific Ocean. The plume appears darkest at its northwestern extremity. Closer to the summit, white puffs appear. They could be part of the plume, or they could be clouds, which often gather over summits.
Pagan Island is a pair of stratovolcanoes—conical volcanoes composed of alternating layers of lava, ash, and rocks—connected by a narrow strip of land. Most of the historic eruptions on this island have occurred on the northeastern volcano. Pagan is part of the Mariana Islands and like its neighbors, results from rising magma as one tectonic plate moves over another. An astronaut photo from 2007 shows the island in more detail.