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.

Perhaps the greatest area of fumarole activity on Earth is the famous Valley of Ten Thousand Smokes[?], adjacent to Katmai volcano[?] in Alaska.