Saturday, August 24, 2019

August 24, 79: An Hour-By-Hour Account Of Vesuvius' Eruption On Its 1,940th Anniversary

From Forbes:
Pliny the Younger reports that it was in the seventh hour after sunrise (right around noon) on August 24th of 79 CE that his mother pointed out to his uncle, Pliny the Elder, that "a cloud of unusual size and shape is appearing." Pliny the Elder was then stationed at Misenum, serving as the commander of the Roman fleet there. In the hours that would follow, thousands would die in the wake of Vesuvius' eruption, their bodies sealed beneath a mixture of ash, rocks and pumice. The popular fascination with Pompeii remains today and new digital efforts to map the continuing excavations within the city serve to reveal the daily life of the people and animals who lived and died in the shadow of Vesuvius. The letters of Pliny, the excavations in and around Pompeii, and volcanological evidence now allow us to reconstruct a timeline for the eruption.
Map of the area around Mount Vesuvius in 79 CE (Map created by the author using 
the Ancient World Mapping Center's Antiquity a la Carte function. UNC-Chapel Hill).
August 24, 79 CE:
12:02 p.m.: Pliny's mother tells his uncle about a cloud appearing overtop Mount Vesuvius. There had been tremors in the days leading up to this, though this was not out of character for the area of Campania. Winds carry much of the ash to the southeast. The "Plinian phase" of the eruption begins.

1:oo p.m.: East of the Volcano, ash begins to fall. Pompeii lies just six miles from Vesuvius.

2:00 p.m.: Pompeii begins to experience ash and then white pumice fall with accumulations continuing at 10-15 cm per hour. There will eventually be a layer 280 cm (3 yards) thick of pumice.

5:00 p.m.: A roof collapses in Pompeii from the weight of the pumice stone and ash. Fist-sized lithics (rocks) are also falling at a speed of 50m per second on the area. The sun is blocked and thus no natural light was available to the people seeking shelter from the eruption. Many rush towards the harbor of Pompeii. Into the evening, a gray pumice begins to fall.

ca. 11:15: The first surge hits Herculaneum, Boscoreale and Oplontis
Midnight: The eruption column above Vesuvius has gone from 14 to 33 km in the air. Pumice and ash enter the stratosphere. In the next seven hours, six pyroclastic surges will hit the area. It is likely that it is in the heat of the surges that many will die. As leading volcanologist Giuseppe Mastrolorenzo noted to National Geographic"temperatures outdoors—and indoors—rose up to 300°C [570°F] and more, enough to kill hundreds of people in a fraction of a second...when the pyroclastic surge hit Pompeii, there was no time to suffocate...The contorted postures are not the effects of a long agony, but of the cadaveric spasm, a consequence of heat shock on corpses."....

Also at Forbes:
Mt. Vesuvius Eruption Exploded Skulls And Vaporized Bodies, Roman Archaeologists Find