An astronaut aboard the International Space Station spotted a steam plume flowing from the northernmost volcano on Pagan Island, part of the Commonwealth of the Northern Marianas.
The commonwealth is an island chain of volcanoes that form the margin between the Pacific Ocean (to the east) and the Philippine Sea (to the west).
Pagan is made up of two stratovolcanoes separated by an isthmus, and it is one of the more volcanically active islands in the Marianas. The island was completely evacuated in 1981 when a large eruption forced the small Micronesian community to flee, according to a NASA statement.
Pagan began steaming and rumbling earlier this year. The most recent update on the volcano from the U.S. Geological Survey says that the plume of gas and steam has been blowing downwind for the past week, but there have been no further reports of activity there.
The islands themselves mark the tectonic boundary where the old, cold Pacific plate is being subducted at the Mariana trench beneath the younger, less dense crust of the Philippine Sea. The subduction results in substantial volcanic activity on the upper plate, forming the island arc of the Marianas. Considered to be one of the classic examples of an oceanic subduction zone, the Mariana Trench includes the deepest spot in the Earth's oceans .
The ISS was located over the Pacific Ocean about 300 miles (480 kilometers) to the southeast of Pagan Island when the image was taken.