Krafla, (818 m) a tuff mountain north of Námafjall. Considerable geothermal heat on the west side of Krafla with fumaroles and mud–springs (solfataras). At the northwest side is Víti, (“Hell”) an ex­plosion crater, 300 m in diameter with green water in the bottom. Leirhnjúkur (“Clay peak”), is west of Krafla and on the southeast side is Hrafntinnu­hryggur, (“Raven flint (i.e. obsidian) ridge”) where pure obsidian is to be found. Construction of a geothermally powered electric plant started in 1974. Its first stage has been completed and provides 30 MW. From 1975–84 there was a series of tremors and eruptions in the area, 9 eruptions altogether along a 7,5 km long fissure. These originated in the old volcano Kröfluaskja.