While most of us associate the eruption of Vesuvius in AD 79 with Pompeii, a new study shows the devastating effects of this natural disaster on the inhabitants of another nearby settlement, Herculaneum.
Researchers have found evidence that “pyroclastic flows,” hot, fast-moving streams of gas and volcanic particles, were crashing into the then-small Roman city.
In an article published in the journal Scientific Reports, a team of geologists from Rome Tre University describes how they found evidence that a lava flow hit Herculaneum shortly after Vesuvius erupted, vaporizing the people living there.
The volcano first erupted, erupting pyroclastic flows (PDC) with extremely high temperatures of 550 °C (1022 °F), vaporizing the population within minutes, while a series of smaller flows with temperatures up to 465 °C (870 degrees Fahrenheit). The city was buried under 65 feet of volcanic deposits.
While most of the bodies in Herculaneum quickly turned into piles of ash, scientists had previously discovered that human tissues turned to glass as a result of this event.
One person’s brain was burned at very high temperatures before it quickly cooled and turned to glass, a process known as vitrification.
The geologists say in their paper: “Although the eruption of Vesuvius in AD 79 was one of the best-studied eruptions, the exact timing and causes of deaths in Pompeii and Herculaneum are still debated.”
They added: “We have shown that the first lava flow to enter the city was a short-lived ash wave with temperatures ranging from 555 to 495 degrees Celsius, capable of causing immediate human death.”
The eruption of Vesuvius in 79 AD destroyed the settlements of Pompeii, Herculaneum, Torre Annunziata and Stabia, killing thousands of people.
The inhabitants of Pompeii were far from the volcano, which means they were not exposed to “pyroclastic flows”. Instead, they were buried alive in the ashes that preserved their remains and most of the city.
On the other hand, the bodies of the people who lived in Herculaneum were poorly preserved after their death, which was a mystery to archaeologists, which prompted them to look for the reason for this.
They collected samples of charred wood from five sites in Herculaneum and studied them using reflection analysis, which evaluates the intensity of energy absorption.
The samples showed traces of exposure to superheated gas for a very short period of time, suggesting exposure to a lava flow.
The first temperature in Herculaneum was at least 550 degrees Celsius, although it likely exceeded that number, according to the team.
This was followed by at least two colder streams with temperatures ranging from 315°C to 465°C, which left thicker volcanic deposits on the ground.
These findings allowed the team to understand the conditions for the formation and preservation of a skull with a vitrified brain inside a victim found at the Collegium Augustalium and reported in 2020.
The victim’s brain was burned at very high temperatures before it was rapidly cooled, turning it into a black glass-like solid, but this was a unique case, as the vast majority of victims in Herculaneum evaporated instantly.
In their article, the experts say that “the transformation of fresh brain tissue into glass in a hot environment can only be achieved if two conditions are met: if the heating is short-term, so that the tissue is not completely evaporated, and once the diluted current has disappeared, the whole body is not buried in sediments” . hot, a necessary condition to ensure the very rapid cooling required to achieve vitrification.”
The team also noted that many of the corpses in Pompeii had a typical post-mortem posture known as the “boxer” posture, with elbows and knees bent and fists clenched.
Bodies exposed to high temperatures often find themselves in this position as their tissues and muscles dry out and contract.
But this does not happen if the temperature is high enough to quickly vaporize the meat from the bone, as shown in Herculaneum, which explains why no surviving corpses like those in Pompeii have been found in Herculaneum.
The team suggests their findings should serve as a warning to modern-day residents of Naples, a city close enough to be affected by the lava flow if Vesuvius erupts again.
They warn that “such a risk deserves more attention for Vesuvius and elsewhere, especially the underestimated risk associated with rising isolated clouds of hot ash, which, although short-lived, can expose buildings to severe thermal damage and lead to loss of life.”
Source: Daily Mail
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