When Mount Vesuvius erupted in 79 AD, the initial blast was so hot it turned the victims’ brains to glass

The eruption of Mount Vesuvius that devastated Italy’s famed Pompeii nearly 2,000 years ago initially released a blast of air so hot it turned the victims’ brains to glass.

A “diluted pyroclastic density current” (PDC) exploded from the volcano at a temperature of about 550C, according to a new study published in the journal Scientific Reports, which used charcoal analysis to reconstruct the event.

The eruption of Mount Vesuvius in AD 79 is one of the most famous – and deadliest – in history, as the victims are largely preserved in the area. Excavations at Pompeii long ago documented a catastrophic pyroclastic flow that descended on the city, a wall of hot gas and rock moving at 80 km/h and temperatures reaching 465°C.

However, to vitrify—turn to glass—organs, as was discovered at nearby Herculaneum, was probably preceded by an even hotter but short-lived stream.

The research team wrote: “The transformation of fresh brain tissue into glass in a hot environment is only possible if two conditions are met: the heating event is short-lived, so the tissue does not completely evaporate, and once the diluted PDC has disappeared, it is A body.” , which is not completely buried in a hot reservoir, a necessary condition to allow for the very rapid cooling required to achieve vitrification.’

This suggests that enough time elapsed between the first and second pyroclastic explosions for the bodies to cool, with only a thin layer of ash deposited at the site, as observed in more recent eruptions, before the slightly cooler but denser flow arrived .

Herculaneum is located almost immediately west of Vesuvius, slightly closer to the volcano than Pompeii is to the southeast. The remains examined were found in the main street of the city.

The team also notes a difference in attitude between the victims at the two locations. In Pompeii, many victims were found in a posture known as the “boxing stance,” with knees bent, elbows, and fists clenched. The pose is often misinterpreted by victims as an attempt to protect themselves, but is generally the result of muscle and body tissue shrinking – in the case of Pompeii due to dehydration from the intense heat.

However, the lack of such evidence in Herculaneum supports the occurrence of an even hotter episode leading to rapid soft tissue disappearance.

The results also have implications for today’s inhabitants around the volcano.

The team wrote: “The red zone at Vesuvius, where the complete evacuation of about 700,000 people is planned in the event of a future eruption, is designed based on the probability of a PC (pyroclastic) invasion inferred from the geological record. While this is certainly the goal to be achieved, it remains uncertain whether the ongoing volcanic unrest will allow enough time to achieve the expected full pre-eruption evacuation.”

Essentially, the new evidence suggests that deadly bursts of hot air could arrive sooner than previous evidence suggested — and upon which current evacuation plans are based.

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They add: “We suggest that despite the need to evacuate all people before the eruption, buildings in the red zone should be reinforced to protect people from the thermal effects of ash plumes if complete evacuation is not possible.” punctual.’