Volcanic dome

Volcanic dome atop Novarupta vent, Valley of Ten Thousand Smokes, Katmai National Park and Preserve, Alaska. The dome was erupted from the same vent that expelled about 15 km3 of magma in an enormous explosive eruption in 1912.

Volcanic domes are rounded, steep-sided mounds built by very viscous magma, usually either dacite or rhyolite. Such magmas are typically too viscous (resistant to flow) to move far from the vent before cooling and crystallizing. Domes may consist of one or more individual lava flows. Volcanic domes are also referred to as lava domes.