The Lost City

Some 2000 years ago, earthquakes awakened the trading town of Pompeii, located at the foot of Mount Vesuvius. 1:00 pm, August 24th, a spectacular eruption ensued, causing a weight of volcanic debris to crush buildings, and a pyroclastic flow (hot gas and volcanic matter) to surge down the flanks of the mount, sweeping over Pompeii. This was the first volcanic eruption to be described in detail, and lives throughout history as one of the most devastating and perhaps one of the most interesting eruptions known.

This mountain is the only active volcano in mainland Europe and is part of the Campanian volcanic arc. A volcanic arc simply refers to a line of volcanoes that results from the subduction of a tectonic plate beneath another, which for Mount Vesuvius, is the African and Eurasian plates.

Mount Vesuvius was not the original geologic feature of this area, but rather it is a cone that has grown in the caldera, which formed from the collapse of a stratovolcano an estimated 17,000 years ago, of the Mount Somma volcano.

Most rocks erupted from Mount Vesuvius are andesite, which put simply is an intermediate volcanic rock with intermediate levels of silica. This silica-rich magma traps explosive gases, it has a high viscosity, meaning it flows slowly, and as a result it blocks the vent as it rises, causing an excess of pressure to build up beneath it. as this magma reaches the surface, the gs is released, resulting in the eruption of the mountain to be particularly explosive, making it unpredictable and often incredibly dangerous.

This explosion, while extremely violent in comparison to many small scale eruptions throughout global history, is most famous for its casts of the victims from Pompeii.

The town of Pompeii, along with its neighbour Herculaneum, disappeared beneath 6 meters of debris, preserving the town’s extremely well, so well in fact 1800 years ago, artifacts have been discovered, allowing a picture to be constructed on the Roman life.

 

 

This eruption killed an estimated 30,000 people and is one of the most fascinating eruptions to have occurred. The city’s destruction is just the thing that has made it so intriguing.

As the pyroclastic flows, otherwise known as pyroclastic density currents, surged down the flanks of the volcano, the civilians were blanketed with this surge, preserving their bodies alongside many artifacts of Roman life.

When the archaeologists began to uncover Pompeii, they found bones trapped within air pockets inside the layers of volcanic ash, pumice and debris, they then filled these air pockets with plaster that solidified in the shape of the body.

Now, with technology advancing, it has been possible to use a multi-layer CT scan to generate images that have never been seen before of inside the casts. These images have led to discoveries surrounding this ancient race, such as the fact that they had perfect teeth, which is most likely directly linked to the healthy diet they led and an abundance of fluorine in the water near Mount Vesuvius.

This mountain still rumbles, while only minor, still shows volcanic activity, imposing the idea that this level of violent activity seen in the eruption 79 AD could resume in the future.

– Alysha Jones

http://volcano.oregonstate.edu/vesuvius

https://www.archaeology.org/slideshow/3928-casts-of-pompeii-slideshow

http://www.slate.com/blogs/atlas_obscura/2015/03/12/plaster_casts_of_victims_bodies_at_pompeii_in_italy.html

https://blogs.scientificamerican.com/history-of-geology/geology-scene-investigation-death-by-volcanic-fire/