Around 1150 bodies have been recovered from Pompeii. Of these, 394 were victims of the early phase of the eruption, found buried beneath layers of pumice. Falling lithics-pumice and rock spewed from the eruption column- killed 10% of these first casualties, while the other 90% died in buildings when roofs and floors collapsed from the weight of ash and from seismic tremors.
But the other 756 were victims of the final stage of the eruption when Vesuvius’s collapsing eruption column released a series of pyroclastic surges-clouds of superheated gas and ash.
It is generally accepted that the victims of the surges suffocated. But recent studies of Pompeii’s body casts suggests that the victims of the surges died a very different kind of death.
The Evidence for Suffocation.
The poses of the body casts have led to the theory that the victims of the pyroclastic surges were asphyxiated by the mix of hot gas and ashes. Casts such as the muleteer seem to be trying to cover their mouths and noses as if to protect themselves from the contents of the air around them.
According to the suffocation theory, the victims would have died an agonizing death. With their first breath, they inhaled a mix of hot carbon dioxide, hydrogen sulfide, hydrogen chloride and sulfur dioxide, which seared the respiratory system. These gases mixed with fine ash, which once inhaled, formed a kind of cement in the lungs. The second breath thickened this mixture, the wind pipe closed and death occurred.
The agony of this death seems to be captured by many of the casts. In the Garden of the Fugitives, a group of people were caught attempting to escape Pompeii in its dying moments by the fifth surge. One man seems to be trying to raise himself up as he was dying, while others are contorted into the ‘pugilistic pose.’
A ‘Post Mortem Stance’
Anthropologist Pier Paolo Petrone disagrees with this interpretation. Dr Petrone has been involved in a close study of 93 well-preserved casts of the surge victims at Pompeii. He does not believe the pugilistic pose indicates the victims suffocated.
“The pugilistic attitude was erroneously thought to be the victim’s attempt for self-defense.” he told the author, “This is exclusively a post-mortem stance. The typical body posture of a suffocated person is a floppy body, mostly standing in an unnatural position, just the opposite of the “life-like” stance of most of victims found in Pompeii. “
Death by Thermal Shock.
Dr Petrone, is one of growing number of experts who believe the bodies actually show signs of death by thermal shock. Dr Peter Baxter, of Cambridge University has also studied the casts from Pompeii as part of his work on the health aspects of volcanic eruptions. He described the affects of thermal shock in an interview with the author:
“The direct heat of the surge would be combined with the radiant heat of the ash particles in the cloud to cause rapid fourth degree burns, i.e., burns extending below the skin layer and into the muscles/deep tissues, with rapid overheating of the blood returning to the heart causing cardiac arrest and/or the brain causing respiratory arrest. “
The Postures of the Pompeii Casts
So what evidence do the body casts from Pompeii offer us of instant death by thermal shock?
The casts can be placed in two groups. One group display the primary postures assumed at the time of death and the other secondary, post mortem postures. Those falling into the primary category all seem to have been frozen in what ever activity they were involved at the moment they died. The post mortem postures are typified by the pugilistic pose.
Dr Petrone and his fellow experts believe the lifelike and often peaceful forms of the primary group of casts are caused by a condition called cadaveric shock.
“Such thermal shock induced an instantaneous muscular stiffening – known as cadaveric spasm – which caused the victims to be frozen in their postures at the time of the impact with the hot ash surge, “ explained Dr Petrone. “The presence of this rare stance is indicative that people were alive at the time of posture arrest and its widespread occurrence is a key evidence that all victims groups were exposed to the same lethal conditions. The predominance of this feature in Pompeii victims points to an instant death due to heat exposure.”
Death by cadaveric shock prevents the normal relaxation of the body after death-which explains why the victims of Pompeii maintained their body posture.
The post mortem ‘pugilistic pose’ is also taken as an indicator of death by thermal shock. Its characteristic ‘clawing’ pose where the victim seems to be struggling against death is in fact caused by the tendons and muscles of the limbs contracting after death due to the extreme heat.
“The burnt muscles contract – shorten as they coagulate – and limbs bend into a position which can’t be straightened even after death, “ explained Dr Baxter.
But why the difference between the two sets of poses? It seems that those sheltering at the time of the surge were more likely to assume a primary pose while the pugilistic pose was common amongst those caught out in the open. “If the temperature was much higher and the all the people were caught in the open then all the bodies would show the same attitude, especially as clothing would ignite in all of the victims.” Dr Baxter said.
But both postures have been identified by Giuseppe Mastrolorenzo, a volcanologist at the Vesuvius Observatory as typified by the victims of nuclear explosions-or volcanic eruptions.
Determining the Temperatures of Pompeii’s Surges.
The thermal threshold for human survival has been determined as 200 Degrees Celsius. Dr. Mastrolorenzo, Dr Petrone and their colleagues have been able to prove that the surges in Pompeii exceeded this level and so were hot enough to kill.
They heated batches of human and horse bones to between 100-800 Degrees Celsius – temperatures compatible with those of the surges emitted by Vesuvius. Burnt bones assume different colors dependent on the heat they were subjected to. The bones of Pompeii’s victims were burnt to a pale yellow. This was the colour of the modern bones heated to temperatures of between 250-300 degrees Celsius.
Hot Enough to Kill-But Not Destroy.
In an experiment shown in a 2013 BBC programme ‘Pompeii: The Mystery of the People Frozen in Time’ , a team from the University of Edinburgh replicated the effects of a pyroclastic surge in Pompeii. They took a piece of pork wrapped in a woolen fabric and exposed it to intense infra red radiation of between 200-250 Degrees Celsius for 150 seconds.
The cloth was left slightly charred but intact and the pork heated but otherwise unchanged. This established that the temperatures in Pompeii were hot enough to kill but they would not have destroyed clothing and soft tissues-which explains why many of the casts show the bodies retaining their forms, clothes, even hairstyles at death.
Thermal Shock Versus Suffocation.
The evidence for thermal shock as the cause of death in Pompeii seems unequivocal. But Dr Baxter does not rule out the part played by asphixiation.
“At Mount St Helens in 1980 people were in the open and the surge was fast moving. Ash was forced into the mouths and lungs – bad news. When the windpipe is blocked you can’t breath by definition,” he explained. “ In a dilute, slow-moving surge if the temperature is low enough you might survive the burns but still eventually die in hospital from lung injury due to burns to the lung tissue from inhaling hot ash. Either heat or suffocation gets you first in the surge itself.”
Paul Wilkinson, Pompeii the Last day, BBC Books, 2003
James M Deem, Bodies from the Ash: Life and death in Ancient Pompeii, Houghton Mifflin Company, 2005
Giuseppe Mastrolorenzo , Pierpaolo Petrone, Lucia Pappalardo, Fabio M. Guarino, “Lethal Thermal Impact at Periphery of Pyroclastic Surges: Evidences at Pompeii”, PLOS One, June 15, 2010
Pompeii: The Mystery of the People Frozen in Time, BBC 2.