Yellow sulfur and other minerals precipitate around high-temperature fumaroles in the Poás summit crater. Fumarole temperatures approaching 600°C were recorded in 1988, several times higher than the melting point of sulfur. The ejection of sulfur clasts as well as small sulfur flows have been documented during several eruptions at Poás.

Photo by Jorge Barquero (Universidad Nacional Costa Rica).

This image is made available under the Creative Commons BY-NC-ND 4.0 license terms.

Keywords: sulfur | mineral deposit | fumarole | geothermal | gas | emissions

Poás