Tuesday, December 1, 2009

August 24, 79 AD

On August 24, 79 AD, Mount Vesuvius blew its top spewing tons of molten ash, pumice, and sulfuric poisonous gas into surrounding neighboring Roman resort cities of Pompeii, Herculaneum, and Stabiae. The falling debris and ash filled the streets until it was completely destroyed and covered. The cities remained buried and undiscovered for almost 1700 years until excavation began in 1748. However, of all the historical evidence scrounged up out of the ash, the letters of Pliny the Younger, found in the 16th century, give a first-hand rendition of the eruptions.

"My dear Tacitus,
You ask me to write you something about the death of my uncle so that the account you transmit to posterity is as reliable as possible. I am grateful to you, for I see that his death will be remembered forever if you treat it [sc. in your Histories]. He perished in a devastation of the loveliest of lands, in a memorable disaster shared by peoples and cities, but this will be a kind of eternal life for him. - Letters from Pliny the Younger"

The Plinian Eruption

The eruption of Mount Vesuvius was a Plinian Eruption. Plinian eruptions are named after Pliny the Elder and Pliny the Younger. Their accounts gave clear views on this classic eruption of Mt. Vesuvius's eruption. These eruptions are probably the most explosive and powerful eruptions of all. They erupt suddenly and unexpectedly after a long quiet period. They occur when utmost viscous magma containing a lot of gas explodes in the depth of the volcano by which the crater pipe functions as the barrel as a shotgun. An enormous amount of gas is shot upwards at high speeds thus, creating an enormous ash cloud. Ashfalls, ashflows, and nuées ardentes (pryclastic flows) occur. Lava flows are emitted when the initial eruptions end. These eruptions can blow volcanic material high into the atmosphere resulting in climate changes. As the eruption ends, the whole summit area collapses forming a caldera.

The Eruption

Days before August 24, 79 AD, tremors shook surrounding cities more frequently. Then suddenly, on August 24, 79 AD, noisy explosions came from Mt. Vesuvius. Hot ash and gas exploded in a column 33 km high before falling on Pompeii at a rate of 12-15 cm/hr.

This was just the beginning.

Around 1 pm, the ash and dust completely covered the skies, causing total darkness. After 8 pm, the eruptions became even more violent. Falling ash and pumice buried neighboring cities of Pompeii, Herculaneum, and Stabiae.

On August 25, 79 AD, at 6:30 am, large earthquakes and
nuées ardentes reached Pompeii. 2.4m of hot ash lay in the streets. Then at 7:30 am, the largest nuée ardente swept through the streets of Pompeii and in 2 minutes, the destruction was complete.

Last Day: August 26, 79 AD, the eruption finally stopped in the morning. 8 cubic km of pumice and ash covered 300 sq. km. of land. Pompeii remained buried until excavations began in 1748.


Now you may wonder, why didn't the inhabitants worry even though they had warning signs such as earthquakes to tell them something wasn't right?

Well despite small earthquakes and other tremors, the inhabitants in the surrounding cities were used to them and didn't pay much attention. However, interestingly, during the eruption, Pliny the Younger mentioned...
"Many besought the aid of
the gods, but still more imagined there were no gods left, and that the
universe was plunged into eternal darkness for evermore." - the 2nd letter from Pliny

The mythology surrounding volcanoes and eruptions comes from the Roman God, Vulcan. After marrying Venus, it is said that whenever she is unfaithful, Vulcan becomes angry and beats the red-hot metal with such a force that sparks and smoke rise up from the top of the mountain, to create a volcanic eruption. Ironically, the eruption of 79 AD happened a day after Volcanalia, the annual festival on August 23.

The Letters of Pliny The Younger to Cornelius Tacitus

A few years after the event, Pliny wrote to his friend Cornelius Tacitus, describing the eruption of Mt. Vesuvius. At the time he was only 18 and living at his uncle Pliny the Elder's villa in the town of Misenum. The two letters are from the Epistulae VI. 16 and the second is VI. 20.

In the first letter, he describes the initial explosion of gas and ash. He describes how his mother warned his uncle of this disaster and just as they were preparing to leave to their boat, a letter was handed to Pliny the Elder The letter was from Rectina, wife of Tascus requesting help. Pliny the Younger then describes his uncle's brave decision to stay behind and save as many people as he could.

The rescuers tried to reach the Pompeii port but couldn't land because of the floating pumice, so he changed his mind and sailed toward Stabiae to reach his friend, Pomponianus, who couldn't leave because of opposing winds. This was his fatal mistake because it brought them to a place where sea escape was impossible. Later when they tried to escape to the sea, the waves were too strong so they were forced to lay on the ground and wait.
Finally, the smell of sulphur caused him to stand up to try and escape to the sea however the fumes choked his windpipe which was already weak from inflammation. Finally when daylight returned on the 26th, 2 days after he had last been seen, Pliny the Younger found Pliny the Elder's body intact and uninjured, fully clothed, but looking asleep rather than dead.

In his second letter, he describes the events he and his mother endured as they made their escape. He with great detail, describes the great darkness that came with the large ash cloud and the chaos that surrounded them.


Sources used

"The 79 AD eruption of Mount Vesuvius, Italy." Explore Italian Volcanoes. Web. 26 Nov. 2009.
Details about the eruption, details about Pliny the Elder and the paths he took to save people, details about the damage the eruption caused.

"Nuees ardentes." Oracle ThinkQuest Library. Web. 26 Nov. 2009. .
definition/descriptions about nuees ardentes.

"Original letters by Pliny the Younger describing Vesuvius." Web. 1 Dec. 2009. .
content of the 2 letters written by Pliny the Younger.

Pliny Letter. Photograph. Pliny Letter MS. Professor Cynthia Damon. Web. 1 Dec. 2009. .
just a snapshot of the original first letter that Pliny the Younger wrote to his friend.

Seach, John. "Mt. Vesuvius Volcano." Volcano Live, John Seach. Web. 26 Nov. 2009. .
Stats about Mt. Vesuvius. Time-line about the events that happened.