Complex volcano

Homa Mountain, Kenya in 1994

An eruption of Pacaya, Guatemala in 1976

Mt. Banahaw, Luzon, Philippines in 1989

Kelimutu, Flores, Indonesia

A complex volcano, also called a compound volcano, is a volcano with more than one feature. They form because changes of their eruptive characteristics or the location of multiple vents in an area. Stratovolcanoes may form complex volcanoes, because they may overlap another from explosive eruptions, lava flows, pyroclastic flows and by repeated eruptions, to make multiple summits and vents. Stratovolcanoes could also form a large caldera that gets filled in by multiple small cinder cones, lava domes and craters may also develop on the caldera's rim.

Although a comparatively unusual type of volcano, they are widespread in the world and in geologic history. Metamorphosed ash flow tuffs are widespread in the Precambrian rocks of northern New Mexico, which describes that caldera complexes have been important for much of the Earth's history. Yellowstone National Park is on three partly covered caldera complexes. The Long Valley Caldera in eastern California is also a complex volcano; the San Juan Mountains in southwestern Colorado are formed on a group of Tertiary-age caldera complexes, and most of the Mesozoic and Tertiary rock of Nevada, Idaho, and eastern California are also caldera complexes and their erupted ash flow tuffs. The Bennett Lake Caldera in British Columbia and the Yukon Territory is another example of a Tertiary-age caldera complex.

Examples

• Akita-Take-Yama (Honshū, Japan)
• Asacha (Kamchatka Peninsula, Russia)
• Asama (Honshū, Japan)
• Kusatsu-Shirane (Kusatsu, Gunma, Japan)
• Banahaw (Luzon, Philippines)
• Bennett Lake Caldera (British Columbia/Yukon, Canada)
• Edziza volcanic complex (British Columbia, Canada)
• Galeras (Colombia, South America)
• Grozny Group (Kuril Islands, Russia)
• Homa Mountain (Eastern Africa, Kenya)
• Irazú Volcano (Costa Rica)
• Ischia (Italy)
• Kelimutu (Flores Island, Indonesia)
• Las Pilas (Nicaragua)
• Long Valley Caldera (California, United States)
• McDonald Islands (Indian Ocean, Australia)
• Mount Meager (British Columbia, Canada)
• Morne Trois Pitons (Dominica)
• Mundua (New Britain, Papua New Guinea)
• Pacaya (Guatemala)
• Puyehue-Cordón Caulle (Chile)
• Rincón de la Vieja Volcano (Costa Rica)
• Silverthrone (British Columbia, Canada)
• St. Andrew Strait (Admiralty Islands, Papua New Guinea)
• Taal Volcano, Batangas, Philippines
• Three Sisters (Oregon) (Oregon, United States)
• Three Kings (New Zealand)
• Valles Caldera (New Mexico, United States)
• Whale Island (New Zealand)
• Yellowstone Caldera (Wyoming, United States)

See also

• Caldera
• Stratovolcano
• Volcanic group