How are active, dormant, and extinct volcanoes classified?

Volcanoes are categorized based on their frequency of eruption and activity into active, dormant, or extinct groups. Active volcanoes have a history of volcanism and are likely to erupt again, while extinct ones lack a magma source and cannot erupt. Dormant volcanoes have not erupted for a long time—often since the start of the Holocene—but retain the potential to erupt in the future.

What we know

• Volcanoes are classified as active, dormant, or extinct based on their frequency of eruption or volcanism. [2]
• Active volcanoes have a history of volcanism and are likely to erupt again, or are currently erupting. [2, 3]
• Extinct volcanoes are not capable of eruption at all because they have no magma source. [2]
• Dormant volcanoes have not erupted in a long time—conventionally since the start of the Holocene—but may erupt again. [2, 3]

Still open

• The categories of active, dormant, and extinct are not entirely uniform and may overlap for certain examples.

Where to go next

• the bigger pictureWhat is the Holocene epoch in geology?
• what caused itHow do tectonic plates create volcanoes?
• how it workedHow do scientists monitor active volcanoes?
• a case in pointWhat caused the last eruption of Mount Scenery?
• how we knowHow did Haleakalā form on Maui?
• an unexpected connectionHow can a dormant volcano still be considered seismically active?Even though dormant volcanoes have not erupted in thousands of years, they are technically considered to be seismically active.

Sources

• [1]volcano (Wikidata Q8072) · CC0 1.0
• [2]Volcano · CC BY-SA 4.0
• [3]Active volcano · CC BY-SA 4.0
• [4]Haleakalā · CC BY-SA 4.0
• [5]Mount Scenery · CC BY-SA 4.0