In volcanology, a lava dome is a circular, mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. [1] Around 6% of eruptions on Earth form lava domes. [1]

Jan 2, 2024 · Lava domes are circular, steep-sided mounds of volcanic rocks formed from the extrusion of viscous lava that piles around a volcanic vent.

Apr 9, 2025 · lava dome The lava dome of Mount St. Helens, May 16, 1984. Following the great eruption of May 18, 1980, a dome of lava grew intermittently in the crater of the volcano. By the time of this photograph, the dome measured 850 metres (2,800 feet) …

Lassen Volcanic National Park contains multiple lava domes. Lassen Peak is the world’s largest dome with a peak elevation of 10,457 feet (3,187 m). It was emplaced 27,000 years ago. Chaos Crags are a set of six lava domes that grew during eruptions approximately 1,050 years ago.

Lava domes are formed by viscous magma being erupted effusively onto the surface and then piling up around the vent. Like lava flows, they typically do not have enough gas or pressure to erupt explosively, although they may sometimes be preceded or followed by explosive activity.

Lava domes are hemispherical to irregularly shaped mounds of volcanic rock (Blake, 1990). They form from lava that is too viscous to flow very far from the vent that extruded it (Husain et al., 2014). The composition is typically andesitic to rhyolitic.

Some lava domes grow in a matter of hours or day, while others may take years – some taking upwards of 100 years to reach their full extent. The stages of development seen below, the Mount St. Helens 1980-1986 lava dome is an example of a composite lava dome that grew episodically.

Volcanic dome, any steep-sided mound that is formed when lava reaching the Earth’s surface is so viscous that it cannot flow away readily and accumulates around the vent. Sometimes domes are produced by repeated outpourings of short flows from a summit vent, and, occasionally, extremely viscous.

Oct 26, 2023 · Basalt lava typically forms thin flows that may reach distances of more than 50 km (30 mi) from their vent. Dacite and rhyolite lavas typically produce short, thick flows that seldom move as far as 5 km (3 mi) from the vent. These short flows often build mound-shaped features called lava domes.

Slowly rising lava domes may grow for months or for several years in the aftermath of explosive eruptions. The earth's longest historical dome-building event has generated the Santiaguito dome in Guatemala. This viscous lava dome began to erupt in 1922 and is still growing today!