by Wendy Graham
October 24, 79 AD — In 79 AD Pliny the Younger was seventeen and staying with his famous uncle, Pliny the Elder, a naturalist, author and naval commander for the Roman fleet at Misenum in the Bay of Naples. His account written as a letter to the Roman historian Tacitus 25 years later made the eruption of Vesuvius famous long after Pompeii was buried under debris and forgotten.
Pliny wrote how the volcanic cloud that initially erupted from the mountain:
"It was not clear at that distance from which mountain the cloud was rising (it was afterwards known to be Vesuvius); its general appearance can be best expressed as being like an umbrella pine for it rose to a great height on a sort of trunk and then split off into branches, I imagine because it was thrust upwards by the first blast and then left unsupported as the pressure subsided, or else it was borne down by its own weight so that it spread out and gradually dispersed." - Epistulae VI.16, VI.20 from the Penguin translation by Betty Radice
Pliny goes on to relate how his uncle then sets off across the bay to Pompeii on a rescue mission, while he stays behind with his mother. His uncle later dies on the beach at Pompeii, his body found the next day. In a second letter Pliny describes his uncles' last moments based on eyewitness accounts. Pliny the Younger is also able to describe in vivid detail his experiences escaping the eruption with his mother in the dark, 19 miles from the volcano, all daylight blocked by the explosion with ash raining down upon them.
Pliny's description of how Vesuvius's column of pumice and ash later collapsed has helped scientists ascertain that the volcano then sent waves of pyroclastic surges at 180-220 °C (360-430 °F) across the countryside burying Pompeii and nearby Herculaneum and killing instantly the estimated 1,500 people still left behind.
So precise was Pliny's memory and description of the large cloud that blew out of Vesuvius that modern volcanologists have termed these types of eruptions Plinian eruptions. Other volcanic eruptions of this type include the 1883 eruption of Krakatoa in Indonesia, Mount St Helen's in the United States in 1980 and Mount Pinatubo in the Philippines in 1991.
The ruins of Pompeii were not rediscovered until 1599 and not properly excavated until 1748 when the discovery of an almost perfectly preserved Roman society caused a sensation across Europe.
Pliny himself went on to have a distinguished career as a Roman official and as a man of letters. Pliny the Younger was our source for the exact date of the eruption, in his Letters he notes it occurred 24 August 79 AD. Curiously in 2018 archaeologists working in Pompeii uncovered notes by a probably a builder repairing a house with the date 16 days before the "calends" of November, or 17 October in modern dating. It now appears probable that the eruption happened 24 October 79 AD instead and that Pliny's Letters had been mistranslated as some point.
Published: August 23, 2017
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