Plinian eruption

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Eruption of Vesuvius in 1822. The eruption of AD 79 would have appeared very similar.

Plinian eruptions are volcanic eruptions marked by their similarity to the eruption of Mt. Vesuvius in 79 AD, which was described in a letter written by Pliny the Younger and which killed Pliny the Elder.

Plinian eruptions are marked by columns of smoke and ash extending high into the stratosphere. The key characteristics are ejection of large amount of pumice, and very powerful continuous gas blast eruptions.

Short eruptions can end in less than a day. Longer events can take several days to months. The longer eruptions begin with production of clouds of volcanic ash, optionally with pyroclastic flows. The amount of magma erupted can be so large the top of the volcano may collapse, resulting in a caldera. Fine ash can deposit over large areas.

The examples of large Plinian eruptions resulting in formation of a caldera are the 1883 Krakatoa eruption (see also Krakatoan Eruption), the 1980 eruption of Mount St. Helens, the 1500 BC Santorini eruption, and the 4860 BC eruption that formed the Crater Lake, and of course Vesuvius in 79 A.D, which was the prototypical Plinian Eruption. The lava is usually rich on silicates; basaltic lavas are atypical for Plinian eruptions, the example is the 1886 eruption of Mount Tarawera.

External links

[USGS Photo Glossary Entry for Plinian Eruptions]

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