The western edge is a
triple junction plate boundary with the
North American plate and
African plate at the seismically active
Azores triple junction extending northward along the
Mid-Atlantic Ridge towards
Iceland. 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. There is another
triple junction where the Eurasian plate meets 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. The boundary between the North American Plate and the Eurasian Plate in the region around Japan has been described as "shifty". 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. 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. 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. ==See also==