Iceland has four major volcanic zones related a divergent
tectonic plate boundary, and a
hot spot: • the
Reykjanes volcanic zone (RVZ), subdivided into the Reykjanes Ridge (RR) (the
Mid-Atlantic Ridge South of Iceland) and the
Reykjanes Volcanic Belt (RVB) (on the main island); • the
West Volcanic Zone (WVZ); • the
East Volcanic Zone (EVZ) (extended to the
Westman Islands, south of the main island as part off the off rift, South Iceland volcanic zone (SIVZ) The classification of volcanic systems depends on volcanology studies and has evolved with time. For example, while Grímsvötn and Þórðarhyrna have similar eruptive compositions, as of 2020 Þórðarhyrna had not been studied in enough detail to have assurance that these are not two separate central volcanoes of two separate volcanic systems. The southern tip of the EVZ propagating rift is an off rift region called the South Iceland volcanic zone (SIVZ), that often has more evolved magma and thus explosive eruptions. North of Iceland, the Mid-Atlantic Ridge is called
Kolbeinsey Ridge (KR) and is connected to the NVZ via the
Tjörnes fracture zone (TFZ). Also the
South Iceland seismic zone (SISZ) is another fracture zone, which connects the EVZ and WVZ. Both fracture zones include their own volcanic systems, smaller than those in the MIB. There are also two intraplate volcanic belts:
Öræfajökull or Öræfi, (ÖVB) on the Eurasian plate, and
Snæfellsnes (SVB) on the North American plate. It is proposed that the east–west line going from the Grímsvötn volcano in the Mid-Iceland Belt (MIB) to the
Snæfellsnes volcanic belt (SVB) shows the movement of the
North American plate over the
Iceland hotspot.
Volcanic systems == See also ==