Bulletin Volcanologique

, Volume 47, Issue 2, pp 295–302 | Cite as

The gas/steam ratio as indicator of heat transfer at the Solfatara fumaroles, Phlegraean Fields (Italy)

  • R. Cioni
  • E. Corazza
  • L. Marini


A simple geochemical model of Solfatara, Phlegraean Fields (Italy), is proposed on the basis of gas composition and temperature at the surface.

Data on the Solfatara fumaroles have been collected since 1979 within the framework of a geochemical monitoring for the surveillance of the Phlegraean volcanic system.

Surface manifestations of Solfatara are likely to be fed through isoenthalpic expansion of dry steam, which separates from a geothermal liquid in an intensively fractured zone at about 236°C. This value is consistent both with gas composition and surface temperature.

The gas/steam ratio appears to be the most effective parameter to detect changes of heat flow at depth.

Actually a remarkable decrease in the gas/steam ratio has been observed since 1981, while the gas composition and the temperature did not change significantly. These facts suggest increased heat flow at depth.


Heat Transfer Steam Surface Temperature Heat Flow Sedimentology 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Intern. Association of Volcanology and Chemistry of the Earth's Interior 1984

Authors and Affiliations

  • R. Cioni
    • 1
  • E. Corazza
    • 1
  • L. Marini
    • 2
  1. 1.Istituto di Geocronologia e Geochimica Isotopica, C.N.R.PisaItaly
  2. 2.Geotermica ItalianaPisaItaly

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