Since the end of Pleistocene glaciation (15.000 - 11.000 years ago in the region), Holocene volcanoes did their work. The Reykjanes Volcanic Belt, one of the volcanic zones of Iceland, is connected to the submarine Reykjanes Ridge (RR), consists of (depending on author) 3-6 or even 7 volcanic systems, arranged en echelon and in an averaged 40° angle to the spreading direction NO-SW over the Peninsula. These volcanic systems are: Eldey Volcanic System (mostly submarine), Reykjanes Volcanic System (not to be confounded with Reykjanes Peninsula), Svartsengi Volcanic System (often thought to be a part of Reykjanes Volcanic System), Krýsuvík Volcanic System (mostly including Fagradalsfjall and Trölladyngja (Krýsuvík)), Brennisteinsfjöll Volcanic System and Hengill Volcanic System, the latter also stretching up to the north and into the West Volcanic Zone. Because of their location on top of a rift segment, these volcanic systems show a tendency for fissure eruptions. The last eruptions in the region took place in the 13th century.