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Heat-damaged bones reveal residents of Herculaneum were not instantly vaporised by Vesuvius

Residents of the Roman town of Herculaneum may not have been instantly vaporised by the Vesuvius, but instead were baked and suffocated to death, a study has found.

Like neighbouring Pompeii, the ancient town was destroyed in the eruption of the volcano Mount Vesuvius in the year 79 AD.

While the streets of Pompeii were buried under 13–20 feet of ash and pumice, Herculaneum was hit by pyroclastic flows — blazing clouds of gas and debris.

While many of the wealthy coastal town's residents evacuated before the eruption, at least 340 people perished as they attempted to shelter in stone boathouses and on the beach.

Although it had been thought that these victims received a mercifully quick death, fresh analysis of the victims' skeletal remains now suggests otherwise.

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Residents of the Roman town of Herculaneum were not instantly vaporised by Vesuvius but instead were baked and suffocated to death, a study has found. Pictured: while many of the town's residents evacuated before the eruption, around 340 took shelter in stone bathhouses

WHAT IS A PYROCLASTIC FLOW?

Pictured: Pyroclastic flows produced by Mayon Volcano, in the Philippines, in 1984

Pyroclastic flows are dangerous and  fast-moving currents of hot gas and volcanic matter that can be produced in an eruption. 

They can form when part of all of the main eruption plume collapses, or as a result of the directional blast when a volcano explodes. 

One of the most deadly volcanic hazards, flows can reach speeds of up to 700 430 mph (700 kph) and temperatures near 1,830 °F (1,000 °C).

One aspect that makes Herculaneum interesting in comparison with Pompeii is its location relative to Mount Vesuvius — which gave the townsfolk more time to evacuate.

'The residents saw the eruption and had a chance to attempt an escape,' said biological anthropologist Tim Thompson of the Teesside University in Middlesbrough.

'It gives a snapshot into the way in which these people responded and reacted to the eruption,' he added.

Although many of the coastal town's population evacuated, around 340 individuals still ended up stranded on the waterfront when the pyroclastic flows swept across the town at some 100 miles per hour (160 kph).

As some of the towns' menfolk hurried to prepare boats on the beach, many women and children took refuge in the vaulted stone boathouses — or 'fornici' — where they would ultimately been unearthed centuries later in 1980.

'They hid for protection, and got stuck. The general theory has been that these individuals were instantly vaporised,' said Professor Thompson.

This notion has been supported by the fact that few of the human remains from Herculaneum were found in the so-called 'pugilistic attitude' — or 'boxer position', with flexed elbows and knees as well as clenched fists.

Bodies subjected to high temperatures often end up in the boxer position as their tissues and muscles dehydrate and contract — but this does not occur if temperatures are high enough to rapidly vaporise this flesh off of the bone.

According to the researchers, the latter requires temperatures from the pyroclastic flow well in excess of 1832°F (1000°C) — and they had doubts as to whether this phenomenon took place at Herculaneum. 

'Vaporisation isn't necessarily in keeping with what we see forensically in modern volcanic eruptions,' Professor Thompson added. 

While many of Herculaneum residents evacuated before the eruption, at least 340 people perished after sheltering in stone boathouses and on the beach

Like neighbouring Pompeii — pictured in this artist's impression — Herculaneum was destroyed in the eruption of the volcano Mount Vesuvius in the year 79 AD

As some of the towns' menfolk hurried to prepare boats on the beach, many women and children took refuge in the vaulted stone boathouses — or 'fornici' — where they would ultimately been unearthed centuries later in 1980

To investigate, the team used techniques to study the Herculaneum boathouse skeletons that they had first developed to study ancient cremations.

Their past work had shown that the crystalline inner structure of skeletons changes depending on the amount of heat they are subjected to, as does the amount of collagen that remains within bone.

They conducted their tests on the ribs of 152 individuals who perished within the fornici — and found that the state of their bones was not consistent with exposure to temperatures in the order of 572–932°F (300–500°C).

'What was interesting was that we had good collagen preservation but also evidence of heat-induced change in the bone crystalline,' said Professor Thompson.

'We could also see that the victims had not been burned at high temperatures.' 

'They hid for protection, and got stuck. The general theory has been that these individuals were instantly vaporised,' said Professor Thompson

This vaporisation theory has been supported by the fact that few of the human remains from Herculaneum were found in the so-called 'pugilistic attitude' — or 'boxer position', with flexed elbows and knees as well as clenched fist — which does not occur if temperatures are high enough to rapidly vaporise this flesh off of the bone.

Instead of having their flesh instantly vaporised, the victims may have lived long enough to unpleasantly suffocate on the toxic fumes of the pyroclastic surge, the researchers concluded — if the heat stress didn't kill them first.

'The heat caused some changes externally, but not necessarily internally to the bones,' Professor Thompson said. 

This suggests that — in the insulated environment of the boathouses, at least — the temperatures from the pyroclastic flow likely did not exceed 752°F (400°C) and may have been as low as 464°F (240°C).

'The walls of the fornici, as well as their own body mass, dispersed the heat in the boathouses, creating a situation that more closely relates to baking,' he added.

PEOPLE WITH GLASS BRAINS 

Pictured, the black glassy matter found inside the skull of the Roman caretaker 

The boathouse victims were not the only Roman townsfolk who perished in Herculaneum during the eruption. 

One man — thought to be aged around 25 — died lying face-down on a wooden bed and was likely asleep when the disaster struck.

The bed was in the Collegium Augustalium — a building owned by an imperial cult which worshipped the former emperor Augustus — and the man was likely its caretaker.

In a separate study published this week, researchers led from from University of Naples Federico II found splatters of a solid, black, glassy material inside the man's skull. 

They believe this was the vitrified remnants of the man's brains — the first ever evidence of such a phenomenon.

Cerebral tissue is normally rarely preserved — but the 'glass' even contained proteins typically found in brain matter.

The conditions impacting the caretaker were different to those that killed the townsfolk sheltering in the boathouses, Professor Thompson told MailOnline.

While the huddled masses in the stone fornici were somewhat insulated from the pyroclastic heat, the caretaker likely faced higher temperatures.

Professor Thompson and colleagues' findings have not only challenged assumptions about how the catastrophe of Vesuvius played out — but have also opened up new areas of investigation.

'Thanks to the collagen preservation in the bones of the Herculaneum victims, we have been able to commence a whole suite of further analyses,' added paper author and archaeologist Oliver Craig of the University of York.

'For example, through stable isotope measurements we have gained a unique snapshot of the Roman diet.' 

Instead of having their flesh instantly vaporised, the boathouse victims may have lived long enough to unpleasantly suffocate on the toxic fumes of the pyroclastic surge, the researchers concluded — if the heat stress didn't kill them first. Pictured, Vesuvius seen in the present day

One aspect that makes Herculaneum interesting in comparison with Pompeii is its location relative to Mount Vesuvius — which gave the townsfolk more of an advanced warning

WHAT DO WE KNOW ABOUT VESUVIUS AND THE DESTRUCTION OF POMPEII?

What happened?  

Mount Vesuvius erupted in the year AD 79, burying the cities of Pompeii, Oplontis, and Stabiae under ashes 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 thought to be one of the most dangerous volcanoes in the world.  

Every single resident died instantly when the southern Italian town was hit by a 500°C pyroclastic hot surge.

Pyroclastic flows are a dense collection of hot gas and volcanic materials that flow down the side of an erupting volcano at high speed.

They are more dangerous than lava because they travel faster, at speeds of around 450mph (700 km/h), and at temperatures of 1,000°C.

An administrator and poet called 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 residents of Pompeii unaware.

Mount Vesuvius erupted in the year AD 79, burying the cities of Pompeii, Oplontis, and Stabiae under ashes and rock fragments, and the city of Herculaneum under a mudflow

He said that a column of smoke 'like an umbrella pine' rose from the volcano and made the towns around it as black as night.

People ran for their lives with torches, screaming and some wept as rain of ash and pumice fell for several hours.  

While the eruption lasted for around 24 hours, the first pyroclastic surges began at midnight, causing the volcano's column to collapse.

An avalanche of hot ash, rock and poisonous gas rushed down the side of the volcano at 124mph (199kph), burying victims and remnants of everyday life.  

Hundreds of refugees sheltering in the vaulted arcades at the seaside in Herculaneum, clutching their jewellery and money, were killed instantly.

The Orto dei fuggiaschi (The garden of the Fugitives) shows the 13 bodies of victims who were buried by the ashes as they attempted to flee Pompeii during the 79 AD eruption of the Vesuvius volcano

As people fled Pompeii or hid in their homes, their bodies were covered by blankets of the surge.

While Pliny did not estimate how many people died, the event was said to be 'exceptional' and the number of deaths is thought to exceed 10,000.

What have they found?

This event ended the life of the cities but at the same time preserved them until rediscovery by archaeologists nearly 1700 years later.

The excavation of Pompeii, the industrial hub of the region and Herculaneum, a small beach resort, has given unparalleled insight into Roman life.

Archaeologists are continually uncovering more from the ash-covered city.

In May archaeologists uncovered an alleyway 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 conical-shaped terra cotta vases that were used to hold wine and oil in ancient Roman times.

The discovery has been hailed as a 'complete novelty' - and the Italian Culture Ministry hopes they can be restored and opened to the public.

Upper stores have seldom been found among the ruins of the ancient town, which was destroyed by an eruption of Vesuvius volcano and buried under up to six metres of ash and volcanic rubble.

Around 30,000 people are believed to have died in the chaos, with bodies still being discovered to this day.