Eruption of Anatahan

Position of center of photo (Lat/Long): [16.35163/145.67776]

The three eruptions have taken a toll on Anatahan. On April 27, the center of the island was completely devoid of plants (shown in red in this false-color, infrared-enhanced image), covered instead by grey volcanic material. Ash appears to have blanketed the western fringe of the island, where a layer of grey covers the underlying vegetation. The light cloud, ash and steam that cover the island make it difficult to see changes to the caldera, but it appears that the eruptions may have destroyed its southern wall. It also appears that volcanic material may have flowed into the Pacific Ocean on the south side of the island.

Anatahan Island sits in the center of the Northern Mariana Islands. The island arc forms a classic arc that frames the eastern edge of the Philippine plate, a large section of the Earth’s crust that floats on a layer of softer rock. To the east of the Marianas, the slab of crust that carries the Pacific Ocean crashes against the Philippine Plate. In the clash, the colder, denser Pacific Plate sinks beneath the Philippine Plate, forming the Mariana Trench, a deep gorge that plunges to a depth of 10,920 meters (35,827 feet) - deeper than Everest is tall and the deepest known point in any ocean. Plummeting deep into the Earth, the Pacific Plate breaks up, and the pressure and the heat melts some of the breaking rock. The hot rock forces its way back to the surface through weak points in the overriding Philippine Plate, creating the arc of volcanoes that make up the Northern Mariana Islands. Among the 14 small islands in the Northern Mariana Islands, there are 12 major volcanoes, including Anatahan.