The Mariana Plate is a small tectonic plate located west of the Mariana Trench

Mariana Trench

The Mariana Trench or Marianas Trench is the deepest part of the world's oceans. It is located in the western Pacific Ocean, to the east of the Mariana Islands. The trench is about long but has a mean width of only...

 and forms the basement of the Mariana Islands

Mariana Islands

The Mariana Islands are an arc-shaped archipelago made up by the summits of 15 volcanic mountains in the north-western Pacific Ocean between the 12th and 21st parallels north and along the 145th meridian east...

. It is separated from the Philippine Sea Plate by a long divergent boundary

Divergent boundary

In plate tectonics, a divergent boundary or divergent plate boundary is a linear feature that exists between two tectonic plates that are moving away from each other. Divergent boundaries within continents initially produce rifts which produce rift valleys...

 with numerous transform fault

Transform fault

A transform fault or transform boundary, also known as conservative plate boundary since these faults neither create nor destroy lithosphere, is a type of fault whose relative motion is predominantly horizontal in either sinistral or dextral direction. Furthermore, transform faults end abruptly...

 offsets. The boundary between the Mariana and the Pacific Plate

Pacific Plate

The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At 103 million square kilometres, it is the largest tectonic plate....

 to the east is a subduction zone with the Pacific Plate subducting beneath the Mariana. The Mariana Trench forms the southeastern boundary and the Izu-Ogasawara Trench

Izu-Ogasawara Trench

The , also known as Izu-Bonin Trench is an oceanic trench in the western Pacific Ocean. It stretches from Japan to the northernmost section of Mariana Trench. The Izu-Ogasawara Trench is an extension of the Japan Trench...

 the northeastern.

The Mariana Islands earthquake of October 31, 2007 was a deep earthquake. It had a magnitude of 7.4 and occurred at 21.980° N. Lat. and 142.685° E. Long. at a depth of 261 km.