Okhotsk microplate
The Okhotsk microplate is a proposed 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.
| Okhotsk microplate | |
|---|---|
| Type | Minor |
| Movement1 | South-west |
| Speed1 | 13–14 mm/year |
| Features | Hokkaido, Kamchatka Peninsula, Kantō, Kuril Islands, Magadan Oblast, Sakhalin Island, Sea of Okhotsk, Tōhoku |
| 1Relative to the African Plate | |
Japan's principal fault system is the zone where the Amurian microplate, the Eastern edge of the Eurasian plate, meets the Okhotsk microplate, sometimes considered the Western edge of the North American plate.
It is controversial whether the northern Honshu, Okhotsk and North American plate constitute separate blocks or plates. "A slightly better fit to data is obtained" when the proposed blocks, Honshu and Okhotsk, are independent of North America, so some studies make this an assumption of their analysis.
The boundary is a left-lateral moving transform fault, the Ulakhan Fault originating from a triple junction in the Chersky Range.