Skip to main content
U.S. flag

An official website of the United States government

Volcanic gas

August 1, 1995

In Roman mythology, Vulcan, the god of fire, was said to have made tools and weapons for the other gods in his workshop at Olympus. Throughout history, volcanoes have frequently been identified with Vulcan and other mythological figures. Scientists now know that the “smoke" from volcanoes, once attributed by poets to be from Vulcan’s forge, is actually volcanic gas naturally released from both active and many inactive volcanoes.

The molten rock, or magma, that lies beneath volcanoes and fuels eruptions, contains abundant gases that are released to the surface before, during, and after eruptions. These gases range from relatively benign low-temperature steam to thick hot clouds of choking sulfurous fume jetting from the earth.

Water vapor is typically the most abundant volcanic gas, followed by carbon dioxide and sulfur dioxide. Other volcanic gases are hydrogen sulfide, hydrochloric acid, hydrogen, carbon monoxide, hydrofluoric acid, and other trace gases and volatile metals. The concentrations of these gas species can vary considerably from one volcano to the next.

Citation Information

Publication Year 1995
Title Volcanic gas
DOI 10.3133/ofr9585
Authors Kenneth A. McGee, Terrance M. Gerlach
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Open-File Report
Series Number 95-85
Index ID ofr9585
Record Source USGS Publications Warehouse
USGS Organization Volcano Science Center