Fumarole With High Speed Gas Ejection Forming Sulfur Crystals. Royalty-Free Stock Photo

A fumarole or fumerole – the word ultimately comes from the Latin fumus, `smoke` is an opening in a planet`s crust which emits steam and gases such as carbon dioxide, sulfur dioxide, hydrogen chloride, and hydrogen sulfide. The steam forms when superheated water condenses as its pressure drops when it emerges from the ground. The name solfatara from the Italian zolfo, `sulfur` is given to fumaroles that emit sulfurous gases.Fumaroles may occur along tiny cracks, along long fissure, or in chaotic clusters or fields. They also occur on the surface of lava or pyroclastic flows.[1] A fumarole field is an area of thermal springs and gas vents where shallow magma or hot igneous rocks release gases or interact with groundwater. When they occur in freezing environments, fumaroles may cause fumarolic ice towers.