How many active volcanoes are there?

Sakurajima, December 30, 1991. Photograph by Mike Lyvers.

The absolute number of volcanoes that exists depends on your definition: active only, active, dormant plus extinct volcanoes? And even if we decide on a definition, nobody has really counted all of the volcanoes, especially the tens on thousands on the sea floor. The best guess is 1511 volcanoes have erupted in the last 10,000 years and should be considered active. This number is from the new Smithsonian Institution book, "Volcanoes of the World: Second Edition" compiled by Tom Simkin and Lee Siebert.

Chuck Wood

Volcanoes of the World, by Simkin, T. and Siebert, L., 1994, Geoscience Press, P.O. Box 42948, Tucson, AZ 85733-2948, (602) 326-9595. A regional directory, gazetteer, and chronology of volcanism during the last 10,000 years. Published in association with the Smithsonian Institution's Global Volcanism Program.

For a review of the book click here