Dome Volcano

Introduction
A dome volcano is a round shaped mountain made of viscous lava. The lava has a high silica content that prevents the lava from flowing very far from its vent. Most domes are formed by dacite and rhyolite lavas.

Dacite dome volcano, Photo by Myrna Martin

Dacite dome in central Oregon, Myrna Martin

Where domes form
Lava domes often form in calderas of stratovolcanoes after a major eruption where the summit of the volcano collapses or is blown away during the eruption. A lava dome has been forming in the crater of Mount Saint Helens after the 1980 eruption of the volcano.

Domes on slopes composite volcanoes
Other small domes form on the side of large composite volcanoes. A lava dome on the slopes of a composite volcano can become unstable when hot lava erupts causing pyroclastic flows to form on its slopes. These deadly pyroclastic flows sweep down the sides of volcanoes killing everything in their path.

Mont Pelee eruptions
The 1902 eruption of Mont Pelee in Martinique was triggered by a lava dome. the pyroclastic flows swept four miles down the side of the volcano killing 30,000 people in the coastal town of St. Pierre.

Mono domes dacite domes in Oregon
Groups of dome volcanoes sometimes form near subduction zones. Small groups of these domes are located in Oregon and California near the Cascadia Subduction Zone. Mono domes and Lassen Peak are examples of domes in California. The picture on this page is one of a group of dacite domes in Oregon.

More Volcano Links

Alaskan Volcanoes Find out more about the Alaskan volcanoes that frequently erupt all along the coast of Alaska.

Lahars-Volcanic Mudflows Find out more about lahars which are triggered by pyroclastic flows, eruptions that can bring death and destruction to people living near volcanoes.

Mount Pinatubo Find out more about the second largest volcanic eruption of the 20th century.

Katmai Volcano Find out more about this Alaskan volcano that was once thought to be the source of the largest volcanic eruption of the 20th century.


Yellowstone Caldera Find out more about Yellowstone and the many features of this supervolcano.

Dome Volcano Find out more about these small crumbly volcanoes that form on the sides of larger volcanoes and in their craters.

Volcano Facts Find out more volcano facts about these mountains of fire that produce Earth eruptions that can alter the weather on our planet sometimes for several years.

Kids Fun Science The links on our home page include information about volcanoes, science activities, plate tectonics, the rock cycle and much