Volcanic gas

Volcanic gases are gases given out by active volcanoes or sometimes not active volcanoes. They come from gases trapped in holes in volcanic rocks, dissolved or separated gases in magma and lava, or gases coming from lava, volcanic craters, or openings. Volcanic gases can also be released through water heated by volcanic activity.

Volcanic gases going into the atmosphere with tephra during eruption of Augustine Volcano, Alaska in 2006.

Volcanic gases on Earth come from sources which include:

• Gases from the Earth's mantle, which include ancient and recycled materials.
• Gases that are absorbed from the Earth's crust.
• Gases taken from groundwater and the Earth's atmosphere.

Volatile substances are materials that can turn into gas or release gases when heated.