Iceland's Perfect Volcanic Crater
Hverfjall (also spelled Hverfell) is one of the world's most perfectly formed tephra cone craters. This massive volcanic crater near Lake Mývatn was created in a single explosive eruption approximately 2,700 years ago. Its nearly perfect circular shape and symmetrical rim make it a textbook example of a volcanic tephra cone.
Hverfjall was created approximately 2,700 years ago in a violent phreatomagmatic eruption when rising magma met groundwater.
Rising basaltic magma encountered groundwater beneath Lake Mývatn, triggering an explosive phreatomagmatic (water-magma interaction) eruption.
The water flashed to steam, creating a massive explosion that fragmented the magma into tiny particles (tephra/scoria) and blasted them into the air.
The volcanic fragments fell back around the vent in a circular pattern, building up the cone symmetrically layer by layer during the eruption.
When the eruption ended, it left behind a deep crater surrounded by a nearly perfect circular rim of loose volcanic tephra.
Hiking to the rim of Hverfjall offers spectacular 360° panoramic views of Lake Mývatn, lava fields, and the surrounding volcanic landscape.
Hverfjall offers incredible photography opportunities. The symmetrical crater is best photographed from a distance to capture its perfect shape - good spots include from Route 1 or from Dimmuborgir area. From the rim, wide-angle lenses capture the crater interior and panoramic views. The black tephra contrasts beautifully with the green summer landscape or white winter snow.
Hverfjall is frequently used in geological education as a textbook example of a tephra cone formed by phreatomagmatic eruption. The crater's exceptional preservation and symmetry make it ideal for understanding volcanic processes. Geology students from around the world visit to study this near-perfect example of explosive volcanism.