While most of us associate the eruption of Mount Vesuvius in 79 AD with Pompeii, a new study has revealed the devastating impact the event had on the inhabitants of another nearby settlement, called Herculaneum.
Scientists have found evidence that “pyroclastic flows” – hot and fast-moving flows of gas and volcanic particles – hit the small Roman city.
The first to hit, estimated at 1,022 °F (550 °C), vaporized the inhabitants within minutes, while a succession of smaller currents at lower temperatures (up to 870°F or 465°C) buried the city under 65 feet of volcanic deposits.
While most bodies at Herculaneum were quickly reduced to piles of ash, researchers have previously found human tissue that was turned into glass by the event.
One the man’s brain had been burned at a very high temperaturebefore rapidly cooling, it transforms into a form of glass – a process known as vitrification.
Pictured are the remains of Herculaneum, a Roman city that was buried under volcanic ash and pumice in the 79 AD eruption of Mount Vesuvius.
The map shows Herculaneum and other cities affected by the eruption. The black cloud represents the general distribution of ash and cinders. Herculaneum was destroyed – along with Pompeii, Torre Annunziata and Stabiae – by the eruption
The new study was led by a team of geologists from the University of Roma Tre and published in the journal Scientific reports.
“Despite the year 79 being one of the most studied eruptions, the exact timing and causes of death in Pompeii and Herculaneum are still debated,” they say in their paper.
‘We show that the first PDC [pyroclastic current] that entered the city was a short-lived ash plume, with temperatures of 555-495°C, which could cause instant death to humans.’
The eruption of Vesuvius in AD 79. destroyed the settlements of Pompeii, Herculaneum, Torre Annunziata and Stabiae, killing thousands in the process, said to be up to 16,000.
After the eruption, bodies of the victims in Pompeii were preserved in a protective shell of ash before eventually decaying.
Since the mid-1800s, the voids these bodies left behind were eventually filled with plaster casts to recreate his last moments.
In comparison, the bodies of people who lived in Herculaneum were not well preserved after they were killed – and the researchers wanted to determine why this was so.
They collected charred wood samples from five sites in Herculaneum and studied them using reflectance analysis, which estimates the intensity of energy absorption.
Illustration of the first pyroclastic density current (PDC) to hit Herculaneum, calculated at 1,022 °F (550 °C)
The samples showed signs of being exposed to a very hot gas for a very short period of time – evidence of exposure to a pyroclastic flow.
The first to enter Herculaneum had a temperature of at least 1,022°F (550°C), although it probably exceeded that number, according to the team.
This was followed by at least two colder currents with temperatures somewhere between 600°F and 870°F (315°C and 465°C) that left thicker volcanic deposits on the ground.
These findings allowed the team to understand the conditions for the formation and preservation of vitrified brain of a victim’s skull in the Collegium Augustalium, reported back in 2020.
The man is believed to have been a caretaker at the headquarters of the Collegium Augustalium, a building owned by an imperial cult that worshiped the former emperor Augustus.
His brain had been burned at a very high temperature before rapidly cooling, turning it into a shiny and solid black glass-like material, but this was a unique case, as the vast majority of victims at Herculaneum would have been instantly vaporized.
The experts say in their paper that “the transformation into glass of fresh brain tissue in a warm environment is only possible if two conditions are met”.
‘[These are if] the heating event is short-lived, so that the tissue is not completely vaporized, and once the dilute current has dissipated, the body is not completely buried in a hot deposit, a necessary condition to allow the very rapid cooling required to achieve vitrification,’ they say .
The team also points out that in Pompeii, many bodies displayed a typical post-mortem posture known as a pugilistic stance or “boxer position”, with bent elbows and knees and clenched fists.
Bodies exposed to high temperatures often end up in this position as their tissues and muscles dehydrate and contract.
Images mark the location of the Herculaneum archaeological site and the ancient city map of Herculaneum with the five sampling sites (b) and (c). Also shown are ash cloud deposits on a few centimeters of black beach sand from the eruption (d)
After the eruption, bodies of the victims in Pompeii were preserved in a protective shell of ash before eventually decaying. Since the mid-1800s, the voids these bodies left behind were eventually filled with plaster casts to recreate their final moments (pictured)
But this does not occur if the temperature is high enough to quickly vaporize this meat from the bone, as can be seen in Herculaneum.
“The lack of such equanimity at Herculaneum testifies to the rapid disappearance of soft tissue, as the pugilistic posture is due to dehydration and shortening of muscles induced by intense heat,” say the experts.
The team suggests their findings should serve as a warning to modern citizens of Naples – a city close enough to feel the effects of a pyroclastic flow should Vesuvius erupt again.
“Such a hazard deserves greater consideration at Vesuvius and elsewhere, particularly the underestimated hazard associated with hot, detached ash clouds, which, even if brief, can expose buildings to severe thermal damage and human death,” they warn.
How Pompeii and Herculaneum were wiped off the map by the devastating eruption of Mount Vesuvius 2,000 years ago
What happened?
Vesuvius erupted in AD 79, burying the cities of Pompeii, Oplontis and Stabiae under ash and rock fragments, and the city of Herculaneum under a mudflow.
Mount Vesuvius, on the west coast of Italy, is the only active volcano in continental Europe and is considered one of the most dangerous volcanoes in the world.
Every single resident died instantly when the southern Italian city was hit by a 500°C pyroclastic heat.
Pyroclastic flows are a dense collection of hot gas and volcanic material that flows down the side of a volcanic eruption at high speed.
They are more dangerous than lava because they travel faster, at speeds of about 450 mph (700 km/h) and at temperatures of 1,000°C.
An administrator and poet named Pliny the Younger watched the disaster unfold from a distance.
Letters describing what he saw were found in the 16th century.
His writing suggests that the eruption caught the inhabitants of Pompeii unawares.
Vesuvius erupted in AD 79, burying the cities of Pompeii, Oplontis and Stabiae under ash and rock fragments, and the city of Herculaneum under a mudflow
He said a column of smoke ‘like an umbrella pine’ rose from the volcano and turned the towns around it as black as night.
People ran for their lives with torches, screaming and some crying as rain of ash and pumice fell for hours.
While the eruption lasted about 24 hours, the first pyroclastic waves began at midnight, causing the column of the volcano to collapse.
An avalanche of hot ash, rock and toxic gas raced down the side of the volcano at 120 mph (199 km/h), burying victims and the remains of everyday life.
Hundreds of refugees sheltering in the vaulted arcades by the sea in Herculaneum, clutching their jewelry and money, were instantly killed.
The Orto dei fuggiaschi (Garden of the Fugitives) displays the 13 bodies of victims buried by the ash as they tried to flee Pompeii during the volcano’s 79 AD eruption.
As people fled Pompeii or hid in their homes, their bodies were covered by flood blankets.
Although Pliny did not estimate how many people died, the event was said to be “exceptional” and the death toll is believed to exceed 10,000.
What have they found?
This event ended the life of the cities but at the same time preserved them until archaeologists rediscovered them almost 1700 years later.
The excavation of Pompeii, the industrial center of the region, and Herculaneum, a small seaside resort, have provided unprecedented insight into Roman life.
Archaeologists are constantly uncovering more from the ash-covered city.
In May, archaeologists uncovered an alley of grand houses, with balconies left mostly intact and still in their original hues.
A plaster cast of a dog, from the House of Orpheus, Pompeii, AD 79. Around 30,000 people are believed to have died in the chaos, with bodies still being discovered to this day
Some of the balconies even had amphorae – the conically shaped terracotta vases used to hold wine and oil in ancient Roman times.
The discovery has been hailed as “complete news” – and the Italian Ministry of Culture hopes they can be restored and opened to the public.
Upper shops have rarely been found among the ruins of the ancient city, which was destroyed by an eruption of Mount Vesuvius and buried under up to six meters of ash and volcanic debris.
Around 30,000 people are believed to have died in the chaos, and bodies are still being discovered to this day.
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