Mývatn Region in detail

Other Features

History & Geology

Ten thousand years ago the Mývatn basin was covered by an ice cap, which was destroyed by fierce volcanic eruptions that also obliterated the lake at its base. The explosions formed the symmetrical móberg peaks (flat-topped mountains formed by subglacial volcanic eruptions) south of today’s lake, while volcanic activity to the east formed the Lúdent tephra complex (tephra is solid matter ejected into the air by an erupting volcano).

Another cycle of violent activity more than 6000 years later created the Ketildyngja volcano, 25km southeast of Mývatn. The lava from that crater flowed northwest along the Laxárdalur valley, and created a lava dam and a new, improved lake. After another millennium or so a volcanic explosion along the same fissure spewed out Hverfjall, the classic tephra crater that dominates the modern landscape. Over the next 200 years, activity escalated along the eastern shore and craters were thrown up across a wide region, providing a steady stream of molten material flowing towards Öxarfjörður. The lava dam formed during the end of this cycle created the present Mývatn shoreline.

Between 1724 and 1729 the Mývatnseldar (Mývatn Fires) eruptions began at Leirhnjúkur, close to Krafla, northeast of the lake. This dramatic and sporadically active fissure erupted again in the 1970s (the Kröflueldar or Krafla Fires), with that episode lasting nine years.

In 1974 the area around Mývatn was set aside as the Mývatn-Laxá Nature Conservation Area, and Hverfjall and the pseudo-crater field at Skútustaðir, at the southern end of the lake, are preserved as national natural monuments.