Strokkur geysir prepares its eruption

by Chiara Arrighi, University of Florence, Florence, Italy

Strokkur is one of Iceland's most famous geysers, erupting once every 6–10 minutes. Its usual height is 15–20 m. Here we see the precursors of a small eruption, which usually takes place shortly after a bigger one (2-3 minutes). The water is boiling and the surface oscillates until the vapor pressure is enough to trigger the fountain. After the eruption, the hot water flows again inside the cone and a new cycle starts. Just wait.