Vestmannaeyjar in the evening

The Vestmannaeyjar Islands consist of a total of 18 islands and islets, as well as 55-60 volcanoes that have been repeatedly conquered. These volcanoes form a special volcanic system, the Vestmannaeyjar system, which is believed to be 70,000 to 100,000 years old. The oldest geological formations above sea level are the North Cliffs on the northernmost part of Heimaey, which were formed about 40,000 years ago. The Helgafell lava flow, which Þorvaldur Thoroddsen believed, according to Landnáma, to be from historical times, has been dated using the radiocarbon method and is believed to be about 5400 years old (Guðmundur Kjartansson, “Nokkrar þýðn C14 aldursákðarðanir”. Náttúrufræðirinn 36 (1967) 126-141).

Geochronological studies indicate that Bjarnarey and Elliðaey, along with Sæfell, are similar in age to Helgafell (5,000-6,000 years), while Stórhöfði is somewhat older. Álsey, Brandur, Suðurey and Hellisey are believed to be around 8,000 years old. Other islands have not been dated. However, the above results indicate that volcanic activity in the area is cyclical. The last cycle may have started with an underwater eruption in 1896 (there are also vague reports of an eruption in 1673), but the Surtsey eruption in 1963 and the Eldfells eruption in 1973 have attracted more attention.