Lake Myvatn is in an area of high volcanic activity. In the last few centuries there have been several major eruptions of volcanoes in this region- Myvatn Fires (1720s) and Krafla Fires (1970-80s). Hverir is a geothermal area on Namafjall mountain east of Myvatn and south of Krafla and just outside Krafla's caldera. Hverir contains multiple mud-pots and fumaroles and the air is redolent of sulfur.