The is a

trough Trough may refer to: In science * Trough (geology), a long depression less steep than a trench * Trough (meteorology), an elongated region of low atmospheric pressure * Trough (physics), the lowest point on a wave * Trough level (medicine), the l ...

that lies off the coast of

Suruga Bay Suruga Bay (駿河湾, ''Suruga-wan'') is a bay on the Pacific coast of Honshū in Shizuoka Prefecture, Japan. It is situated north of a straight line from Omaezaki Point to Irōzaki Point at the tip of the Izu Peninsula and surrounded by Honshū ...

in Japan, forming part of the

Nankai Trough The is a submarine trough located south of the Nankaidō region of Japan's island of Honshu, extending approximately offshore. The underlying fault, the ''Nankai megathrust,'' is the source of the devastating Nankai megathrust earthquakes, wh ...

, the latter being responsible the source of many large earthquakes in Japan's history. Both mark the boundary of the

Philippine Sea Plate The Philippine Sea Plate or the Philippine Plate is a tectonic plate comprising oceanic lithosphere that lies beneath the Philippine Sea, to the east of the Philippines. Most segments of the Philippines, including northern Luzon, are part of ...

subducting Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...

under the

Amurian Plate The Amurian Plate (or Amur Plate; also occasionally referred to as the China Plate, not to be confused with the South China Subplate) is a minor tectonic plate in the northern and eastern hemispheres. It covers Manchuria, the Korean Peninsula ...

See also