The Okhotsk plate is a minor tectonic plate covering the Kamchatka Peninsula, Magadan Oblast, and Sakhalin Island of Russia; Hokkaido, Kantō and Tōhoku regions of Japan; the Sea of Okhotsk, as well as the disputed Kuril Islands.
Japan's principal fault system is the zone where the Amur plate, the Eastern edge of the Eurasian plate, meets the Okhotsk plate, sometimes considered the Western edge of the North American plate.
The Izanagi plate (named after the Shinto god Izanagi) was an ancient tectonic plate, which began subducting beneath the Okhotsk plate 130–100 Ma (million years ago). The rapid plate motion of the Izanagi plate caused northwest Japan and the outer zone of southwest Japan to drift northward. High-pressure metamorphic rocks were formed at the eastern margin of the drifting land mass in the Sanbagawa metamorphic belt, while low-pressure metamorphic rocks were formed at its western margin in the Abukuma metamorphic belt. At approximately 55 Ma, the Izanagi Plate was completely subducted and replaced by the western Pacific plate, which also subducted in a northwestern direction. Subduction-related magmatism took place near the Ryoke belt. No marked tectonics occurred in the Abukuma belt after the change of the subducted plate.
The discovery of an extinct Jurassic–Cretaceous spreading system in the northwest Pacific led to the introduction of the extinct Kula plate in 1972. The Izanagi plate was subsequently introduced in 1982 to explain the geometry of this spreading system. Knowledge of the former Izanagi plate is limited to Mesozoic magnetic lineations on the Pacific plate that preserve the record of this subduction.
The Amur plate (or Amurian plate; also occasionally referred to as the China plate, not to be confused with the Yangtze plate) is a minor tectonic plate in the northern and eastern hemispheres.
The Amurian Plate is named after the Amur River, which forms the border between the Russian Far East and Northeast China.It is bounded on the north, west, and southwest by the Eurasian plate, on the east by the Okhotsk plate, to the southeast by the Philippine Sea plate along the Suruga Trough and the Nankai Trough, and the Okinawa plate, and the Yangtze plate.
The Kuril–Kamchatka Trench or Kuril Trench (Russian: Курило-Камчатский жёлоб, Kurilo-Kamchatskii Zhyolob) is an oceanic trench in the northwest Pacific Ocean. It lies off the southeast coast of Kamchatka and parallels the Kuril Island chain to meet the Japan Trench east of Hokkaido. It extends from a triple junction with the Ulakhan Fault and the Aleutian Trench near the Commander Islands, Russia, in the northeast, to the intersection with the Japan Trench in the southwest.
The trench formed as a result of the subduction zone, which formed in the late Cretaceous, that created the Kuril island arc as well as the Kamchatka volcanic arc. The Pacific plate is being subducted beneath the Okhotsk plate along the trench, resulting in intense volcanism.
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 the Philippine Mobile Belt, which is geologically and tectonically separate from the Philippine Sea plate.
The plate is bordered mostly by convergent boundaries: To the north, the Philippine Sea plate meets the Okhotsk microplate at the Nankai Trough. The Philippine Sea plate, the Amurian plate, and the Okhotsk plate meet near Mount Fuji in Japan. The thickened crust of the Izu–Bonin–Mariana arc colliding with Japan constitutes the Izu Collision Zone. The east of the plate includes the Izu–Ogasawara (Bonin) and the Mariana Islands, forming the Izu–Bonin–Mariana Arc system. There is also a divergent boundary between the Philippine Sea plate and the small Mariana plate which carries the Mariana Islands. To the east, the Pacific plate subducts beneath the Philippine Sea plate at the Izu–Ogasawara Trench. To the south, the Philippine Sea plate is bounded by the Caroline plate and Bird's Head plate. To the west, the Philippine Sea plate subducts under the Philippine Mobile Belt at the Philippine Trench and the East Luzon Trench. (The adjacent rendition of Prof. Peter Bird's map is inaccurate in this respect.) To the northwest, the Philippine Sea plate meets Taiwan and the Nansei islands on the Okinawa plate, and southern Japan on the Amurian plate.It also meets the Yangtze plate due northwest.
The Japan Trench is an oceanic trench part of the Pacific Ring of Fire off northeast Japan. It extends from the Kuril Islands to the northern end of the Izu Islands, and is 8,046 metres (26,398 ft) at its deepest. It links the Kuril–Kamchatka Trench to the north and the Izu–Ogasawara Trench to its south with a length of 800 kilometres (497 mi). This trench is created as the oceanic Pacific plate subducts beneath the continental Okhotsk microplate (a microplate formerly a part of the North American plate). The subduction process causes bending of the down going plate, creating a deep trench. Continuing movement on the subduction zone associated with the Japan Trench is one of the main causes of tsunamis and earthquakes in northern Japan, including the megathrust Tōhoku earthquake and resulting tsunami that occurred on 11 March 2011. The rate of subduction associated with the Japan Trench has been recorded at about 7.9–9.2 centimetres (3.1–3.6 in)/yr.
The Ulakhan Fault is a left-lateral transform fault that runs along the boundary between the North American plate and the Okhotsk microplate in northeast Asia. It runs from a triple junction in the Chersky Range in the west, to another triple junction with the Aleutian Trench and the Kuril Trench in the east. From the offset of dated geomorphological features, a slip rate of 5.3±1.3 mm per year has been measured, consistent with estimates from GPS-constrained global plate models. The analysis of fault scarps along the fault zone in the Seymchan Basin suggests that the fault is characterised by occasional large (Mw>7.5) earthquakes.