Fumaroles arise when there is little water in the depths. Due to the lack of pressure, the water is completely converted into steam before it exits . Fumaroles are classified by the temperature and type of gases they emit. The temperatures of the gases can be between 200 ° C and 800 ° C. Most fumaroles excrete pure water vapor, but often other volcanic gases also escape, some of which are deposited at the point of exit. By oxidation and thermophilic (heat-loving) bacteria occurs as the characteristic of Fumarolen colored staining. Exhalations rich in sulfur compounds like hydrogen sulfide are called solfataras ; Carbon dioxide exhalations are called mofettes . In the vicinity of mofets lying in depressions, the carbon dioxide can accumulate, as it is heavier than air, and thus lead to death from suffocation in animals and humans .
Display of volcanic activity
Through changes, fumaroles can indicate volcanic activity. If their temperature rises or the composition of the escaping gas changes drastically, this can be an indication of a new volcanic eruption . For example, the temperatures of the fumaroles on the island of Vulcano , which has been quiet for over 100 years, rose from 300 ° C to over 700 ° C between 1986 and 1993, which caused great concern. It was only when the temperatures dropped again that the all-clear could be given.
- A. de Bylandt Palsterkamp: Théorie de Volcans. Volume 3. Levrault, Paris 1835 (reprint). Adamant Media Corporation, Chestnut Hill MA 2001, ISBN 0-543-72498-0 .
- Georg Landgrebe: Natural history of the volcanoes and the associated phenomena. Volume 1. Perthes, Gotha 1855 (reprint. Cambridge University Press, Cambridge et al. 2011, ISBN 978-1-108-02860-8 ).
- USGS: Photo Glossary (English)