These Victims of the Infamous Vesuvius Eruption Were Baked From the Outside in, Scientists Say

People trying to escape the Roman settlement of Herculaneum during the infamous eruption of Mount Vesuvius in A.D. 79 died a slower death than previously thought, and were likely being baked from the outside in, research suggests.

The eruption spewed out vast amounts of ash and volcanic rock, which buried the the town of Pompeii. Meanwhile, pyroclastic flows—fast-moving currents of hot gas and volcanic matter which can reach speeds of around 400 miles per hour and temperatures of 1,800 degrees Fahrenheit—also destroyed nearby Herculaneum, its more affluent coastal neighbor.

As residents fled Herculaneum, many took refuge in so-called fornici—a series of vaulted stone boathouses located on the beachfront—in the hopes of protecting themselves. But the skeletons of at least 340 people have been found in these fornici—individuals who died as a result of the pyroclastic flows.

It was previously thought that the soft tissue of these individuals would have vaporized due to the heat given off by the pyroclastic flows, killing them instantly. However, a study published in the journal Antiquity suggests that this may not have been the case.

The authors of the study re-examined the ribs of 152 victims found in the fornici, finding that the structure of their bones and collagen—an abundant protein found in the body—did not match up with would be expected if they had been vaporized.

"There were two results that were really interesting," Tim Thompson, an author of the study from Teeside University in the U.K., told Newsweek. "The analysis of the changes to the inorganic crystal structure of the bone suggested a lower temperature of exposure than some have previously argued."

"The second was that we found a significant amount of collagen had survived, which does not happen with usual cremations. These results, combined with our understanding of the body positions and their location within the stone boat houses, suggested a different manner of death than direct exposure to fire and heat," he said.

Thompson argues that instead of being vaporized, the victims appeared to have been slowly baked from the outside by the pyroclastic flows. These may have been cooler than expected—perhaps around 450 degrees Fahrenheit—and it is also likely that the fornici provided some insulation, thus lowering the temperature the victims were exposed to. As a result, the the scientists argue that the residents could have lived long enough to die from inhaling toxic fumes.

Herculaneum, fornici, human remains
Human remains discovered in the fornici at Herculaneum. Thompson et al.

"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," Thompson said in a statement. "The heat causes some changes externally but not necessarily internally to the bones."

"[The study] has given us a more nuanced understanding of what happened on that day, and what the residents experienced during and just after the eruption. We can also apply this new understanding to the modern, forensic context too," he told Newsweek.

The Vesuvius eruption is one of the most notorious natural disasters in history, and is also hugely important from an archaeological perspective given that the volcanic material has preserved Pompeii, Herculaneum and other nearby sites, providing a snapshot into Roman life at the time of the event.

"This is one of the best known volcanic eruptions which resulted in the unprecedented preservation of life and times in the Roman period," Thompson said.