Volcanic gases include a variety of substances given off by active (or, at times, by dormant) volcanoes. These include gases trapped in cavities (vesicles) in volcanic rocks, dissolved or dissociated gases in magma and lava, or gases emanating directly from lava or indirectly through ground water heated by volcanic action.
The sources of volcanic gases on Earth include:
Substances that may become gaseous or give off gases when heated are termed volatile substances.
Vulcano (Sicilian: Vurcanu) is a small volcanic island in the Tyrrhenian Sea, about 25 km (16 mi) north of Sicily and the southernmost of the eight Aeolian Islands. It is 21 km2 (8 sq mi) in area, rises to 499 m (1,637 ft) above sea level, and contains several volcanic centers, including one of four active non-submarine volcanoes in Italy.