Mariana Plate

Here, the Pacific Plate is subducted under the Mariana Plate.

The earthquake was in the region where the Pacific Plate subducts beneath the Mariana Plate.

At the boundary, the western edge of the Pacific Plate is subducted beneath the small Mariana Plate.

The islands are part of the island arc that is formed on the over-riding plate, the Mariana Plate, on the western side of the trench.

The seamount and its nearby peers were created by the movement of crushed rock, resulting from plate movement, upwards through fissures in the Mariana Plate.

In this system, the western edge of one plate, the Pacific Plate, is subducted beneath the smaller Mariana Plate that lies to the west.

There is also a divergent boundary between the Philippine Sea Plate and the small Mariana Plate which carries the Mariana Islands.

The Mariana Plate is a small tectonic plate located west of the Mariana Trench and forms the basement of the Mariana Islands.

The island chain arises as a result of the western edge of the Pacific Plate moving westward and plunging downward below the Mariana plate, a region which is the most volcanically active convergent plate boundary on Earth.

The islands are formed as the highly dense and very old western edge of the Pacific plate plunges downward to form the floor of the Mariana Trench, and carries trapped water under the Mariana plate as it does so.

The Pacific Plate thrusts under the Mariana Plate at the Mariana Trench, and the Mariana Plate is separated from the Philippine Sea Plate by a spreading ridge, the Mariana Trough.

Although the broad-scale tectonics of this region are dominated by the subduction of the Pacific Plate beneath the Philippine Sea Plate, the Pacific Plate does not reach the Philippine Sea Plate in this region, as the Mariana Plate is located in between.

Because the Pacific plate is the largest of all the tectonic plates on Earth, crustal material at its western edge has had up to 170 million years to compact and become very dense; hence its great height-difference relative to the higher-riding Mariana Plate, at the point where the Pacific Plate crust is subducted.

South Chamorro Seamount and the other mud volcanoes formed as a result of the subduction of the Pacific Plate below the Mariana Plate; fault lines in the Mariana Plate provide a gateway for churned up rock and fluid from the grinding process up to the ocean surface.