Plume from Mount Pagan. North Pagan Volcano released a thin volcanic plume, likely rich in sulfur dioxide, on March 25, 2013. The volcano has been active nearly continuously since April 2011. This natural-color satellite image was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Aqua satellite.

Pagan is located about 320 kilometers (200 mi) north of Saipan, the main island of the Northern Mariana Islands. With an area of 47.23 km2 (18.24 sq mi), it is the fourth largest island of the Northern Marianas. The island is a double island consisting of two stratovolcanoes joined by a narrow strip of land with a width of only 600 meters (660 yd). The southern volcano 18.075°N 145.725°E, is 548 m (1,798 ft) high with a caldera approximately 4 km (2.5 mi) in diameter, consisting of four craters joined together. Although several fumaroles were active in 1992, the southern volcano last erupted in 1864. The northern volcano, also known as Mount Pagan, 18.13°N 145.8°E, has a height of 570 m (1,870 ft). The volcano is in the center of a caldera with a diameter of approximately 6 km (3.7 mi), and eruptions have been documented in the 1820s, 1872–1873, 1925 and 1981–85.
Pagan has two large lakes. Laguna Sanhalom (also Inner Lake) had an area of 17 hectares (42 acres) and depth of 23 m (75 ft) in the 1970s. Laguna Sanhiyon (also Laguna Lake) on the west coast of the northern island had an area of 16 hectares (40 acres) and depth of 20 m (66 ft). Both lakes contain brackish water. Plume from Mount Pagan has spread.

Credit: NASA image courtesy Jeff Schmaltz LANCE/EOSDIS MODIS Rapid Response Team, GSFC.