Oceanography (Mar 2010)
Spotlight 10: Northwest Rota-1 Seamount
Abstract
Northwest Rota-1 Seamount is the first place on Earth where a submarine volcanic eruption was witnessed in 2004, and, remarkably, the volcano appears to have been in a state of continuous eruption ever since. NW Rota-1 is located ~ 100 km north of Guam in the western Pacific, within the newly designated Mariana Trench Marine National Monument (http://www.fws.gov/marianastrenchmarinemonument/). With a summit depth of 520 m, it is a symmetrical cone of basaltic andesite composition formed in the subduction zone setting of the Mariana volcanic arc. It was identified as a site of particular interest in 2003 when sampling of its overlying hydrothermal plume showed very high magmatic volatile input. Consequently, it was one of several seamounts targeted for dives with a remotely operated vehicle the following year. During these dives, an actively erupting vent was discovered at a depth of 550 m; lava, fluid, and gas samples were collected; and colonies of shrimp, limpets, and crabs (some of them new species) were found living in the volcano summit’s harsh conditions.
