NW Rota-1

Geography & Climate

NW Rota-1 is located in United States, within the Mariana Volcanic Arc of the broader Northwestern Pacific Volcanic Regions. Situated at 14.60° N, 144.78° E in the Northern Hemisphere, the volcano lies within a tropical climate zone. With an elevation of -455 meters — below sea level — NW Rota-1 is a submarine or submerged volcanic feature. Submarine volcanoes make up the majority of Earth's volcanic activity, though most eruptions go unobserved beneath the ocean surface. The volcanic landform is characterized as a composite, which describes the physical shape and structure of the volcanic edifice as observed from the surface.

Geological Context

NW Rota-1 sits in a subduction zone, where one tectonic plate dives beneath another, creating intense heat and pressure that generates magma. Subduction zones are responsible for many of the world's most explosive volcanoes and deadliest eruptions. For communities in United States near NW Rota-1, this tectonic setting means the volcano is capable of producing powerful explosive eruptions, pyroclastic flows, and lahars that can threaten populated areas within tens of kilometers of the summit. The dominant rock type is basalt / picro-basalt, a dark, fine-grained volcanic rock that forms from rapidly cooling, low-viscosity lava. Basaltic eruptions tend to be less explosive and produce fluid lava flows that can travel long distances. While less immediately dangerous than explosive eruptions, basaltic lava flows can destroy structures and infrastructure in their path, and volcanic gases released during these eruptions can affect air quality over a wide area.

Eruption History Summary

NW Rota-1 has 1 recorded eruption in the geological database, spanning from 2003 CE to 2003 CE. With eruptive activity as recently as 2003 CE, NW Rota-1 remains an actively monitored volcano.

GVP Reference Summary

A submarine volcano detected during a 2003 NOAA bathymetric survey of the Mariana Island arc was found to be hydrothermally active and named NW Rota-1. The basaltic to basaltic andesite seamount rises to within 517 m of the ocean surface SW of Esmeralda Bank, 64 km NW of Rota Island and ~100 km N of Guam. When Northwest Rota-1 was revisited in 2004, a minor submarine eruption from a vent named Brimstone Pit on the upper south flank about 40 m below the summit intermittently ejected a plume several hundred meters high containing ash, rock particles, and molten sulfur droplets that adhered to the surface of the remotely operated submersible vehicle. The active vent was funnel-shaped, about 20 m wide and 12 m deep. Prominent structural lineaments about a kilometer apart cut across the summit of the edifice and down the NE and SW flanks.

— Smithsonian Institution, Global Volcanism Program