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Plinian eruptions or Vesuvian eruptions are Volcano eruptions characterized by their similarity to the eruption of Mount Vesuvius in 79 AD, which destroyed the ancient Roman cities of Herculaneum and Pompeii. The eruption was described in a letter written by Pliny the Younger, after the death of his uncle Pliny the Elder.
Plinian eruptions eject columns of volcanic rock and volcanic gas high into the stratosphere, the second layer of Earth's atmosphere. They eject a large amount of pumice and have powerful, continuous gas-driven eruptions.
Eruptions can end in less than a day, or continue for days or months. The longer eruptions begin with production of clouds of volcanic ash, sometimes with pyroclastic surges. The amount of magma ejected can be so large that it depletes the magma chamber below, causing the top of the volcano to collapse, resulting in a caldera. Fine ash and pulverized pumice can be deposited over large areas. Plinian eruptions are often accompanied by loud sounds. The sudden discharge of electrical charges accumulated in the air around the ascending column of volcanic ashes also often causes lightning strikes, as depicted by the English geologist George Julius Poulett Scrope in his painting of 1822 or observed during 2022 Hunga Tonga–Hunga Ha'apai eruption and tsunami.
The lava is usually dacitic or rhyolitic, rich in silica. Basaltic, low-silica lavas rarely produce Plinian eruptions unless specific conditions are met (low magma water content <2%, moderate temperature, and rapid crystallization); a recent basaltic example is the 1886 eruption of Mount Tarawera on New Zealand's North Island.
Pliny the Elder set out to rescue the victims from their perilous position on the shore of the Bay of Naples, and launched his , crossing the bay to Stabiae (near the modern town of Castellammare di Stabia). Pliny the Younger provided an account of his death, and suggested that he collapsed and died through inhaling poisonous gases emitted from the volcano. His body was found buried under the ashes of the eruption with no apparent injuries on 26 August, after the plume had dispersed, which would be consistent with asphyxiation or poisoning, but also with a heart attack, asthma attack, or stroke.
The threshold for ultra-Plinian eruptions is an eruptive column height of , or more recently. The few instances of eruptions that lie at the transition between Plinian and ultra-Plinian include the P3 phase of 1257 Samalas eruption, 1991 eruption of Mount Pinatubo, the Plinian phase of the Campanian Ignimbrite, Bandelier Tuff,Self, Stephen; Wolff, John ; Wright, John (2021-12). Tsankawi Pumice Fall Unit B, a Very Widespread and Powerfully Emplaced Plinian Deposit. AGU Fall Meeting 2021. and the 1902 eruption of Santa María.
The once unequivocal ultra-Plinian classification of the Hatepe eruption has been called into question, with recent evidence showing that it is an artifact of an unrecognized shift in the wind field rather than extreme eruptive vigor.
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