What tectonic plate is located west of a trench which reaches a maximum-known depth of 10994 m?
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.
Large low-shear-velocity provinces Large low-shear-velocity provinces, LLSVPs, also called superplumes, are characteristic structures of parts of the lowermost mantle (the region surrounding the outer core) of the Earth. These provinces are characterized by slow shear wave velocities and were discovered by seismic tomography of the deep Earth. There are two main provinces: the African LLSVP and the Pacific LLSVP. Both extend laterally for thousands of kilometers and possibly up to 1000 km vertically from the core-mantle boundary. The Pacific LLSVP has specific dimensions of 3000 km across and 300 m higher than the surrounding ocean-floor, and is situated over four hotspots that suggest multiple mantle plumes underneath. These zones represent around 3% of the volume of the Earth. Other names for LLSVPs include "superwells", "thermo-chemical piles", or "hidden reservoirs". Some of these names, however, are more interpretive of their geodynamical or geochemical effects, while many questions remain about their nature.