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| Eurasian Plate | |
|---|---|
Eurasian Plate
| |
| Type | Major |
| Approximate area | 67,800,000 km2 (26,200,000 sq mi)[1] |
| Movement1 | south |
| Speed1 | 7–14 mm (0.28–0.55 in)/year |
| Features | Europe (including part of Iceland), Asia, Atlantic Ocean, Arctic Ocean |
| 1Relative to the African Plate | |
The Eurasian Plate is a tectonic plate that includes most of the continent of Eurasia (a landmass consisting of the traditional continentsofEurope and Asia), with the notable exceptions of the Indian subcontinent, the Arabian subcontinent and the area east of the Chersky Range in eastern Siberia. It also includes oceanic crust extending westward to the Mid-Atlantic Ridge and northward to the Gakkel Ridge.
The western edge is a triple junction plate boundary with the North American Plate and Nubian Plate at the seismically active Azores Triple Junction extending northward along the Mid-Atlantic Ridge towards Iceland.[2][3] Ridges like the Mid-Atlantic ridge form at a divergent plate boundary. They are located deep underwater and very difficult to study. Scientists know less about ocean ridges than they do the planets of the solar system.[4]
There is another triple junction where the Eurasian Plate meets the Anatolian Sub-Plate and the Arabian Plate. The Anatolian Sub-Plate is currently being squeezed by the collision of the Eurasian Plate with the Arabian Plate in the East Anatolian Fault Zone.[5][6]
The boundary between the North American Plate and the Eurasian Plate in the area around Japan has been described as "shifty".[7] There are different maps for it based on recent tectonics, seismicity and earthquake focal mechanism. The simplest plate geometry draws the boundary from the Nansen ridge through a broad zone of deformation in North Asia to the Sea of Okhotsk then south through Sakhalin Island and Hokkaido to the triple junction in the Japan Trench.[8] But this simple view has been successfully challenged by more recent research. During the 1970s, Japan was thought to be located on the Eurasian Plate at a quadruple junction with the North American Plate when the eastern boundary of the North American Plate was drawn through southern Hokkaido. New research in the 1990s supported that the Okhotsk microplate was independent from the North American Plate and a boundary with the Amurian microplate, sometimes described as "a division within the Eurasian plate"[additional citation(s) needed] with an unknown western boundary.[9][10]
All volcanic eruptions in Iceland, such as the 1973 eruption of Eldfell, the 1783 eruption of Laki and the 2010 eruption of Eyjafjallajökull, are caused by the North American and the Eurasian plates moving apart, which is a result of divergent plate boundary forces.
The convergent boundary between the Eurasian Plate and the Indian Plate formed the Himalayas mountain range. The geodynamics of Central Asia is dominated by the interaction between the Eurasian Plate and the Indian Plate. In this area, many sub-plates or crust blocks have been recognized, which form the Central Asian and the East Asian transit zones.[11]
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The Anatolian tectonic block (sub-plate) is being affected by converging plate movements that occur between the Arabian-African and Eurasian plates (e.g. Armijo, Meyer, Hubert, & Barka, Citation1999; Bozkurt, Citation2001; Jackson & McKenzie, Citation1984; Le Pichon, Chamot-Rooke, Lallemant, Noomen, & Veis, Citation1995; McKenzie, Citation1972, 1978; Şengör, Citation1979, 1980; Sengör, Görür, & Saroglu, Citation1985; Taymaz, Jackson, & McKenzie, Citation1991). As a result of this collision, the North Anatolian (NAF) and East Anatolian (EAF) transform faults have been formed. The Anatolian sub-plate is bounded to the north and east by these faults. The impingement started to move the sub-plate westward and resulted compression and uplifts near the Karlıova triple junction in the Eastern Anatolia. As a result of anti-clockwise rotational movement of the Anatolian sub-plate in a westward direction four different neotectonic regions have been formed namely: (1) East Anatolian compressional region, (2) North Anatolian region, (3) Central Anatolian 'ova' region and (4) West Anatolian extensional region (Sengör et al., Citation1985).
Hence, the problem: geodetic models imply a plate boundary between Japan and Eurasia, but published geological and seismological evidence does not support placing it in the Japan Sea or at the ISTL. If, as studies show, almost half of the convergence between North America and Eurasia is taken up in Hokkaido and across N Japan, the small amount of remaining convergence may be difficult to distinguish given the large elastic response in the upper plate (N Honshu) after the 2011 Tohoku-oki (M9.0) earthquake, and strong coupling at the megathrust. To draw such a plate boundary on tectonic maps implies a degree of certainty about its location which is unfounded
