Vulcanian Eruptions

volcano with minor ash eruption
Redoubt volcano with minor ash eruption. Photograph taken during observation and gas data collection flight by AVO staff March 30, 2009.

Photo by Heather Bleick, public domain from USGS.


Vulcanian eruptions are moderately explosive but intermittent, producing moderate ash columns. These eruptions are more explosive than Strombolian, and sometimes destroy part of the volcanic edifice. Vulcanian eruptions are propelled by exsolution of volatiles in magmas beneath a solidified plug of lava. They may also have a phreatomagmatic component.

Vulcanian eruptions usually consist of small volumes of magma, but form vigorous eruption columns made up of highly fragmented ash. These eruption columns may be dark in color and rise to moderate heights. Large blocks and bombs, including breadcrust bombs, may be ejected during the eruption. Pyroclastic flows are also produced during Vulcanian eruptions, sometimes from the collapse of volcanic domes.

Vulcanian eruptions can occur from a range of volcano types including composite volcanoes, cinder cones, and domes.

  • Typical magma composition: intermediate

  • Description: Explosive

  • Eruption Products: volcanic blocks, breadcrust bombs, tephra, pyroclastic flows, lahars

  • National Park examples: Trident Volcano in Katmai National Park and Preserve, Redoubt Volcano in Lake Clark National Park and Preserve, Lassen Volcanic National Park

Trident Volcano in Katmai National Park and Preserve erupted intermittently from 1953-1974, often in the Vulcanian style, sending ash columns into the atmosphere. Redoubt Volcano in Lake Clark National Park and Preserve experienced Vulcanian eruptions in March 2009. In 1915, Vulcanian eruptions occurred at the Lassen volcanic center in Lassen Volcanic National Park.

Related Links

Part of a series of articles titled Volcanic Eruption Styles.

Katmai National Park & Preserve, Lake Clark National Park & Preserve, Lassen Volcanic National Park

Last updated: April 14, 2023