Holocene volcanism in Iceland is mostly to be found in the "Neovolcanic Zone", comprising the Reykjanes Volcanic Belt (RVB), the West Volcanic Zone (WVZ), the Mid-Iceland Belt (MIB), the East Volcanic Zone (EVZ) and the North Volcanic Zone (NVZ). Two lateral volcanic zones play a minor role: Öræfi Volcanic Belt (ÖVB) and Snæfellsnes Volcanic Belt (SVB). Outside of the main island are the Reykjanes Ridge (RR), as part of the Mid-Atlantic Ridge to the southwest and the Kolbeinsey Ridge (KR) to the north. Two transform zones are connecting these volcano-tectonic zones: the South Iceland Seismic Zone (SISZ) in the south of Iceland and the Tjörnes Transform Zone (TFZ) in the north.