Fumarole

Derived from the Latin fumus, smoke, a fumarole is an opening in Earth's (or any other astronomical body's) crust, often in the neighborhood of volcanoes, which emit steam and gases such as carbon dioxide, hydrochloric acid, and hydrogen sulfide. The name solfatara, from the Italian solfo, sulfur (via the Sicilian dialect), is given to fumaroles that emit sulfurous gases.

A good example of fumarole activity on Earth is the famous Valley of Ten Thousand Smokes, which was formed during the 1912 eruption of Novarupta in Alaska. Initially, there were thousands of fumaroles in the cooling ash from the eruption, but over time most of them have become extinct.