Mývatn was formed after a massive eruption 2300 years ago, and it remains geothermally active today. The lake is located along the western side of the volcanic zone which bisects Iceland and is an extension of the Mid-Atlantic Ridge. The features of the landscape are quite new in geologic times, with most of the land shaped by activity occurring since the last Ice Age.
The inhabitants of the surrounding area, called Mývatnssveit, are approx. 450 but many more live there in the summer to service tourists. Lately there has been a movement among the local entrepreneurs to increase tourism in the winter so now some hotels are open during the winter and tours are offered, including go-carting on ice and ice-bowling as well as jeep rides over snowy terrain.
Flora and fauna
Due to the number of wetlands surrounding the lake there are an exceptional number of waterbirds, and the area is recognized as one of the premier bird-watching sites in the world. Over 115 species of birds have been sighted at the lake, including thirteen species of ducks that nest in the lake area. Most nesting birds arrive in late April or early May. The most abundant species is the tufted duck, followed by the greater scaup and wigeon. Other commonly sighted species include the Barrow's goldeneye, red-breasted merganser, gadwall, mallard, common scoter, long-tailed duck and teal. Harlequin ducks and the Barrow's goldeneye breed nowhere else in Europe. Other birds likely to be seen at the lake include the tufted Slavonian grebe, red-necked phalarope, common loon great northern diver, red-throated diver and whooper swan.
One of the reasons why so many birds congregate in the lake area is due to the massive number of aquatic insects - visitors are advised to bring mosquito netting with them to avoid the often-bloodthirsty hordes of black flies that can be found here.
During the last Ice Age much of the Mývatn was covered by glaciers. Eruptions below the ice led to the formation of some of the area's mountains. Major volcanic events since that time have occurred 3800 years ago, 2500 years ago, 2300 years ago, and during a series of eruptions lasting from 1724 until 1729. Most recently, eruptions of the Krafla volcano from 1975 until 1984 produced fresh lava flows in the area. This volcanic activity is seen today in the relatively shallow lake, the many pseudocraters that surround it, and the fantastic lava formations and craters in the area.