Lethal Thermal Impact at Periphery of Pyroclastic Surges: Evidences at Pompeii

Public Library of Science ^ | June 2010 | Giuseppe Mastrolorenzo, Pierpaolo Petrone, Lucia Pappalardo, Fabio M. Guarino

[SunkenCiv]

The evaluation of mortality of pyroclastic surges and flows (PDCs) produced by explosive eruptions is a major goal in risk assessment and mitigation, particularly in distal reaches of flows that are often heavily urbanized. Pompeii and the nearby archaeological sites preserve the most complete set of evidence of the 79 AD catastrophic eruption recording its effects on structures and people.

Here we investigate the causes of mortality in PDCs at Pompeii and surroundings on the bases of a multidisciplinary volcanological and bio-anthropological study. Field and laboratory study of the eruption products and victims merged with numerical simulations and experiments indicate that heat was the main cause of death of people, heretofore supposed to have died by ash suffocation. Our results show that exposure to at least 250°C hot surges at a distance of 10 kilometres from the vent was sufficient to cause instant death, even if people were sheltered within buildings. Despite the fact that impact force and exposure time to dusty gas declined toward PDCs periphery up to the survival conditions, lethal temperatures were maintained up to the PDCs extreme depositional limits.

This evidence indicates that the risk in flow marginal zones could be underestimated by simply assuming that very thin distal deposits, resulting from PDCs with poor total particle load, correspond to negligible effects. Therefore our findings are essential for hazard plans development and for actions aimed to risk mitigation at Vesuvius and other explosive volcanoes.

[SunkenCiv]

Also, parachuting into live volcanoes is often dangerous.

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[SunkenCiv]

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[ClearCase_guy]

pyroclastic surges and flows (PDCs)

Acronym FAIL.
They could have explained a density current. Just use the words and tell us it's also known as surges and flows. Why dumb down everything?

[Interesting Times]

Interesting. Evidently extreme heat caused all the fatalities in Pompeii as well as Herculaneum, which is not what was previously believed.

[UCANSEE2]

Maybe, instead of worrying about dropping a nuke into the BP Oil well leak, we should just drop nukes into volcanoes, and eliminate all that nasty CO2.

And the cost per volcano is very cheap compared to what it would take to put one 15,000 feet under the ocean floor.

Since no one could then parachute into a live volcano, it would save lives.

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What I meant to say was , Thanks for posting this article. It is amazing what we can still find, given the time that has passed.

[stboz]

I've visited Pompeii. Vesuvio is NOT really close-by. Pretty creepy when you think about it.

Gives meaning to the phrase "We're toast!"

[Jack Hydrazine]

It was the Doctor who caused Vesuvius to blow!

Fires of Pompeii trailer
http://www.youtube.com/watch?v=7AKjx_amhZw

Part 1
http://www.youtube.com/watch?v=oG2118hhT50&feature=PlayList&p=202F9722BD5AAB0C&playnext_from=PL&playnext=1&index=62

[Trillian]

I’ll take note of that.

[Quix]

WOW.

THX.

[zot]

Thanks for the ping. This study says that extreme heat killed people somewhat beyond the area covered by the pyroclastic flow. That makes sense. But I think a lot of people were smothered by falling ashes in areas that were not covered by the pyroclastic flow.

[HospiceNurse]

Lethal Thermal Impact at Periphery of Pyroclastic Surges: Evidences at Pompeii

Of course! The blowdown from the caldera would have obscured the dacite coronal polymorphic schist protruberances. The density current would have been indirectly proportional to the diatreme. The ejecta would have been preceded by fumarolic activity similar to that of the Eocene.

Calling Dr. Obvious.

[SunkenCiv]

The original shake and bake. ;’)

[SunkenCiv]

LOL!

[SunkenCiv]

And wear clean underwear.

[SunkenCiv]

Since he has that time machine, he’s SOL when it comes to having an alibi for anything that’s ever happened. No wonder he moves around a lot and has plastic surgery to change his appearence every so often.

[Quix]

INDEED.

[SunkenCiv]

When there’s a threat of becoming toast, it’s a good idea to spread out, or butter yet, to crust get out of town.

[SunkenCiv]

Oh sure, just traipse on in and wreck everything. ;’)

[SunkenCiv]

In Herculaneum, I believe the only human remains ever found were carbonized bones. Since the pyroclastic flows came straight down onto the town, assuming most didn’t just get out when the quakes started, the heat may have just vaporized most of the victims. I’d like to go sometime, particularly to H to places off-limits to tourists. There are doors still on working hinges, one of the gymnasiums still has the sporting equipment in orderly stacks on the floor (a yearly athletic contest was under way when the mountain blew its stack), upper storeys are preserved...