Cross section across the Mariana Plate
The Mariana Plate is a small tectonic plate located west of the Mariana Trench and forms the basement of the Mariana Islands. It is separated from the Philippine Sea Plate by a long divergent boundary with numerous transform fault offsets. The boundary between the Mariana and the Pacific 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 the northeastern boundary.
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.