Topic summary
Okhotsk microplate
Extracted from the Wikipedia article Okhotsk plate.
Proposed microplate
During the 1970s Japan was thought to be located on the Eurasian plate at a quadruple junction with the North American plate, the Pacific plate and the Philippines Plate. At that time the western boundary of the North American plate was drawn through southern Hokkaido. In the 1980s, the boundary of the North American plate was extended to the Japan Sea and the Itoigawa-Shizuoka Tectonic Line (I-STL) due to earthquakes occurring at the eastern edge of the Japan Sea. 1990s research supported a proposal of an Okhotsk microplate independent from the North American plate.