Fumaroles
Volcano Learning zone > Volcano Glossary
Fumaroles are vents from which volcanic gases escape, carbon dioxide,sulphur dioxide,hydrochloric acid,hydrogen sulhide and water vapour. Temperatures can give a good indication of the what is going on inside the volcano and can be 100s of degrees C. They occur along cracks,fissures and weaknesses. Mineral deposits can form as the hot gas hits the cooler air. Changes in the temperature of fumaroles can indicate changes to the activity levels of the volcano.Sulphur deposits occur around fumaroles as bright yellow deposits and crystals.