The Pompeii catastrophe did not have much of a secret. The eruption of Vesuvius caused thousands of deaths and practically destroyed this Roman city, as well as Herculaneum, in 79 AD. What was no longer so clear was the way in which all those people died.
The debate in recent decades has been intense. Perhaps it was the strong heat that melted their bodies (with temperatures between 300 and 600º), perhaps they died crushed by the pyroclastic material and the collapse of the buildings, or it was the clouds of toxic gases that created an unbreathable environment.
A team from the University of Valencia set out to finally unravel the mystery. For this, he resorted to the study of the plaster casts that were created from seven victims of Vesuvius who perished in the areas of Porta Nola and Terme Suburbane (a bathhouse) of Pompeii, as explained in an article published in the magazine PLOS ONE.
In the 1870s, archaeologists excavating the city discovered peculiar air pockets among the rubble, many of which contained human remains. They injected plaster into these holes, creating 3D models of the victims' bodies and freezing them in time.
These casts are an unusual testimony to the final moments of these people, but as Gianni Gallello, the study's lead author, acknowledges, this rare "fingerprint from the past" is destructive because the chemicals in the plaster have corrupted much of the remains, difficult to analyze.
Hence, the researchers used X-ray fluorescence to determine the elemental composition of both the bones and the plaster that formed around them. Although they consider that high temperatures and contamination can alter the results, they defend that "suffocation" was the most probable cause of death of these victims.
It is likely that the inhabitants of Pompeii did not die in a single catastrophic event. The volcano erupted in two main phases, firstly spewing hot gases, ash and pulverized pumice that brought down Pompeii's rooftops and trees. Some inhabitants were crushed, but many others managed to escape.
Then came a series of "pyroclastic surges" in which turbulent masses of hot ash and lava swept away the remaining people and structures. Experts agree that most of the Pompeii victims died in this second phase.
The Porta Nola bodies were placed on a thick layer of pumice, suggesting that they survived the first phase of the eruption. They probably tried to flee the city when pyroclastic material stopped falling, something they wanted to be extremely difficult because of the debris, Gallello says.
Two victims suffered broken legs and another appears to have used a fallen tree branch as a makeshift walking stick. X-rays made it possible to identify bones that remained relatively intact to contamination. They compared the best preserved with other remains that were intentionally buried in a cemetery or cremated in Pompeii or Rome before the eruption. Although the chemical composition indicates that the human remains in the molds most closely resembled the cremated remains, there is other evidence showing that the burning occurred after a slow death.
Previous studies had analyzed evidence found in the neighboring city of Herculaneum, which was also destroyed in 79 AD. Many of these skeletons were contracted in a rigid "boxer's position", characteristic of rapid death by vaporization or dehydration.
However, the Pompeian bodies examined now lay face down in a relaxed position, suggesting a slow death from suffocation or exhaustion. Impressions in the plaster show that some victims covered themselves with their clothing, trying to avoid breathing the ashes.
Gas hot enough to evaporate bodily fluids would also have burned clothing, Gallello explains. Hence, he considers it more likely that the victims died of suffocation during a lower temperature pyroclastic flow and were buried under a layer of volcanic ash during the beginning of the second phase of the eruption.
After the death of these people, the gases and the hottest lava would have settled on the bodies, heating the ashes and burning the clothes and flesh of the victims, leaving behind only a few charred bones and a few human-shaped voids. .
