
Mount Vesuvius eruption: Extreme heat 'turned man's brain to glass' - neversaydie
https://www.bbc.com/news/world-europe-51221334
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Zimahl
There's a CG video of the last 24 hours of Pompeii[0] which shows how the city
was completely wiped off the map. It's probably one of the best ways to
visualize the disaster and aftermath.

[0]:
[https://www.youtube.com/watch?v=dY_3ggKg0Bc](https://www.youtube.com/watch?v=dY_3ggKg0Bc)

~~~
jtwaleson
I'm by no means an expert on any of this, but the visualization seems way too
slow. When you see how the bodies of people were found, I think it went a lot
faster than this video implies.

~~~
dredmorbius
Pyroclastic flows have been directly measured at up to 90-130 m/s (200-290
mph), though even more typical speeds of 10-100 m/s (22 - 220 mph) exceed the
pace of a walking human in good shape, let alone the elderly, young, or
infirm. I'm not aware of specific indicated speeds of the 79 CE Vesuvius
flows.

Escape on foot would have been at ~5 kph (3 mph). The safest destination from
Pompeii, we can say in 2020 with hindsight, would have been _perpendicular_ to
the wind flow, to the north-east, at least 10 km (3+ hours continuous
walking), up-hill.

Keep in mind that modern vulcanology, meterology, risk analysis, and disaster
mitigation were also in their infancies, as well as wide-area information
broadcasting, making such information largely unavailable at the time. In
particular, the likely "obvious" safety of water (south-west) lead not only
toward the centre of the kill zone, but a dead end as well. Walking strictly
away from Vesuvius would reduce risk, but involved a longer path to safety
than the NE route.

[https://en.wikipedia.org/wiki/Eruption_of_Mount_Vesuvius_in_...](https://en.wikipedia.org/wiki/Eruption_of_Mount_Vesuvius_in_79#/media/File%3AMt_Vesuvius_79_AD_eruption.svg)

Few people at the time had access to SUVs, high-speed watercraft, helicopters,
motorcycles, or bicycles, to aid in escape.

The wind was blowing onshore, a factor substantially credited to the death of
Pliny the Elder, who, with the words "Fortune favours the brave" had attempted
a sea rescue with his naval fleet, but found itself trapped at the beach.
Pliny died there.

Temperatures within the cloud were a _minimum_ of 100C (212F), and reached as
much as 360C (500F) or more, all deadly. Wood and human remains at Herculaneum
show carbonisation -- effectively having been turned into charcoal.
Temperatures were extreme.

The surges themselves occurred well into the eruption, after substantial
damage to the city by both earthquakes and bombardment, lasting overnight.

Total volcanic deposits on Herculaneum, which was spared windblown ash and
hence resulted _only_ from pyroclastic flows, were _23 meters_ (75 feet).
Digging your way out of 7 storeys of searing-hot rock is a challenge for many
people.

Any remaining survivors at the time of the surge would likely have been in
terror, sleep deprived, utterly confused by the transformation to their
surroundings, and probably not most able to have escaped in the first place.
The eruption occurred during a festival in which the local population would
have been increased by tourists and visitors. In Pompeii, though the initial
pyroclastic surge saw lower temperatures close to the ground, later surgers
(by surviving evidence) saw consistent temperatures throughout the vertical
column, even at or below ground level. Surviving in a basement or cellar was
not an option.

Total population of Pompeii and Herculaneum is estimated at ~16-20k, with
about 1,500 bodies having been identified to date. Total victims clearly lie
somewhere between these two numbers, and there's little agreement as to the
precise number, though a fair argument can be made that mortality was a
minimum of 10-20%.

At some point, if you were within the kill zone of Vesuvious, regardless of
your mental state or fitness, you were walking dead. You might not have been
dead yet, but there was simply no way out or to survivable shelter. There
_was_ no survivable shelter within the zone.

Again: by midnight August 28, if you were anywhere but heading north-east of
Pompeii, or north-west of Herculaneum, you were already dead.

~~~
scrollaway
> _Few people at the time had access to SUVs, high-speed watercraft,
> helicopters, motorcycles, or bicycles, to aid in escape._

This is potentially one of the biggest Pompeii-related understatements of the
day, even.

~~~
dredmorbius
Oh, I sprinkled a few of those in there.

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dmix
To others who were curious of the definition as I was:

 _vitrified_ \- To change or make into glass or a glassy substance, especially
through heat fusion.

[https://en.wikipedia.org/wiki/Vitrification](https://en.wikipedia.org/wiki/Vitrification)

~~~
deliveryboyman
The definition follows in the next sentence of the article.

~~~
dmix
Yes, I see that now thanks. I saw the term used earlier in the article and
jumped the gun!

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klyrs
And we thought brain freeze was bad...

Shame that the vitrified brain matter melted into a puddle. The title
momentarily got my hopes up that we might see the structure of a 2k year-old
brain.

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coldcode
Sitting here reading this in pleasant A/C its hard to imagine your brain
glassifying at 560°C in a fraction of a second.

