Hverfjall

Hverfjall is a bare, perfectly round bowl of dark grey-black volcanic debris rising from the flat lava country east of Lake Mývatn in north Iceland. About a kilometre across at the rim, it reaches 420 metres above sea level, and its smooth, unvegetated slopes make it one of the most clearly shaped volcanic craters in the country — a giant ring of gravel that seems to have been set down on the plain in a single stroke.

That is close to the truth. Hverfjall (also called Hverfell) is a tephra cone or tuff ring, formed in one explosive eruption around 2,500 years ago in the southern part of the Krafla fissure swarm, the volcanic system that still dominates the Mývatn district. When rising magma met water in the ground, the violent interaction shattered both into fine fragments that fell back around the vent to build the steep circular wall. Tephra from the eruption was spread over the whole Mývatn area. The southern side of the ring is less regular than the rest, a disruption thought to come from a landslide during the eruption. Much later, during the Age of Settlement, lava from the Svörtuborgir craters near Námafjall flowed around Hverfjall and almost surrounded it.

From the rim the view takes in Lake Mývatn, the surrounding lava fields and the lava labyrinth of Dimmuborgir just to the south. The loose tephra slopes are fragile, and only two marked paths, from the northwest and from the south, lead to the rim; walking on the slopes elsewhere is not allowed.

Getting there

Hverfjall stands a few kilometres south-east of the village of Reykjahlíð on Lake Mývatn. The nearest city is Akureyri, about 57 km to the west in a straight line, and Akureyri Airport (AEY) is about 56 km away. The Ring Road (Route 1) runs through the Mývatn area, with a side road leading towards the crater.