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Where Is the Mariana Arc?

GeologyOceanography

Quick Answer

The Mariana Arc is a chain of volcanic islands and submarine volcanoes in the western Pacific Ocean, running parallel to the Mariana Trench — it stretches about 1,200 km from Guam northward to near Japan.

The Full Story

The Mariana Arc is a volcanic arc formed by subduction of the Pacific Plate beneath the smaller Mariana Plate. As the dense oceanic Pacific Plate dives into the mantle, water released from it lowers the melting point of the overlying mantle rock, generating magma that rises to form a chain of volcanoes. The arc includes the 15 islands of the Mariana chain (including Guam, Saipan, and the Northern Mariana Islands) and over 60 submarine volcanoes (seamounts). Some are highly active: NW Rota-1 was filmed erupting underwater in 2006, providing the first direct observation of a deep submarine eruption. The arc is famous for its hydrothermal vent systems, which support chemosynthetic ecosystems including unique species of shrimp, tube worms, and bacteria. The Mariana volcanic arc sits about 200 km west of the Mariana Trench, the deepest point in the oceans at 10,994 metres.

Key Facts

1.The Mariana Arc contains over 60 submarine volcanoes, many of which are actively erupting or venting hydrothermal fluids.
2.NW Rota-1 submarine volcano was filmed erupting in real-time in 2006 by NOAA scientists — the first direct observation of an erupting deep-sea volcano.
3.The Mariana Trench, which parallels the arc, reaches 10,994 metres — deeper than Mount Everest is tall.

YouTube Angle

Suggested video title for this topic:

"The Mariana Arc — Underwater Volcanoes at the Edge of the Deepest Trench"