Archaeologists have hotly debated the precise cause of death of those who perished in Pompeii when Mount Vesuvius erupted in 79 CE. Did they die of asphyxiation, from the extreme heat, or from a combination of factors? A new paper published in the journal Frontiers in Earth Science examines the complicating effects of earthquakes that occurred just prior to and concurrently with the eruption. Of most interest was the discovery of two skeletons of people who likely died when their shelter collapsed around them, weakened by the seismic tremors.

As previously reported, the eruption of Mount Vesuvius released thermal energy roughly equivalent to 100,000 times the atomic bombs dropped on Hiroshima and Nagasaki at the end of World War II, spewing molten rock, pumice, and hot ash over the cities of Pompeii and Herculaneum in particular. Archaeologists believed that the vast majority of the victims died of asphyxiation, choking to death on the thick clouds of noxious gas and ash.

However, a 2001 study in Nature, co-authored by University of Naples archaeologist Pierpaolo Petrone, estimated a temperature of 500° Celsius (932° Fahrenheit) for the pyroclastic surge that destroyed Pompeii, sufficient to kill inhabitants in fractions of a second. In 2018, we reported on Petrone's conclusion that inhabitants of Herculaneum may have suffered a similar fate. He observed fracturing in the bones of some 100 excavated skeletons, as well as "cracking and explosion" of the skullcaps, consistent with forensic cases where skulls burst from extreme heat.

Petrone's 2020 follow-up study offered additional evidence that extreme heat killed many victims, based on analysis of one victim's skull in particular, first excavated in the 1960s from Herculaneum. There was evidence of brain matter remains in the skull. Usually such brain matter would be "saponified" by the extreme heat—that is, it turned to soap (glycerol and fatty acids). But this victim's brain matter had been vitrified, i.e., fused into glass. Later that year, Petrone reported fresh evidence that this might, indeed, have been the case, announcing his discovery of preserved human neurons in the victim with the "glassified" brain, although other scientists expressed skepticism about that finding.

A 2023 multidisciplinary analysis of seven plaster casts from Pompeii concluded that these victims, at least, likely survived the early eruption and died some 20 hours later from asphyxiation, although the authors were careful to emphasize that their findings were only applicable to these particular cases. "It is likely that the catastrophic eruption killed people in different ways," the authors of that 2023 study wrote, concluding that "generalizing and supporting a sole hypothesis of death becomes overly reductive."

Seismic shocks

Now we have yet another twist: Some Pompeii residents may have perished due to the cumulative effects of earthquakes and aftershocks. According to Domenico Sparice, a volcanologist at INGV-Osservatorio Vesuviana, and co-authors, there is historical evidence of seismic activity in the decades prior to the 79 CE eruption. For instance, an earthquake in 62–63 CE caused extensive damage to buildings in Pompeii such that repairs were still underway 17 years later.