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Plinian Eruption


Plinian eruptions, also known as Vesuvian eruptions, are volcanic eruptions marked by their similarity to the eruption of Mount Vesuvius in 79 AD, which destroyed the cities of Herculaneum and Pompeii. The eruption was described in a letter written by Pliny the Younger; it killed his uncle, Pliny the Elder.

Plinian eruptions are marked by columns of gas and volcanic ash extending high into the stratosphere, the second layer of Earth's atmosphere. The key characteristics are ejection of large amount of pumice and very powerful continuous gas blast eruptions. According to the Volcanic Explosivity Index, Plinian eruptions have a VEI of 4, 5 or 6.

Short eruptions can end in less than a day, but longer events can take several days to months. The longer eruptions begin with production of clouds of volcanic ash, sometimes with pyroclastic flows. The amount of magma erupted 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 can deposit over large areas. Plinian eruptions are often accompanied by loud noises, such as those generated by Krakatoa.

The lava is usually rhyolitic and rich in silicates. Basaltic lavas are unusual for Plinian eruptions; the most recent basaltic example is the 1886 eruption of Mount Tarawera on New Zealand's North Island.

Pliny described his uncle's involvement from the first observation of the eruption:


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