Last year, scientists discovered two male skeletons riddled with bone fractures, evidence that during a brief interval in the eruption, a powerful earthquake toppled buildings and crushed people in their homes.
The team spent months piecing together the stories of these victims, two men in their 50s whose injuries bore an eerie resemblance to modern victims of building collapses during earthquakes. Drawing on expertise in volcanology, anthropology and archaeosis, the researchers conclude in the journal Frontiers in Earth Science that the men likely survived the first phase of the eruption and were sheltering in a house when a wall collapsed on them, knocked down by a strong earthquake.
The study is unusual because it drew on the expertise of scientists from many fields. Raffaello Cioni, a volcanologist at the University of Florence who was not involved in the work, called the analysis “really accurate and convincing.”
For centuries, Pompeii has been a source of dark fascination for scientists and the general public. A historical account of the eruption by Pliny the Younger, a lawyer and author, describes tremors that shook the ground before and during the eruption. But deciphering a clear earthquake signature has been difficult, since so many destructive forces overlapped chaotically.
“This is a very complex task, recognizing the effects of an earthquake during an eruption, because both phenomena can happen in succession, or simultaneously,” said Domenico Sparice, a volcanologist at the Vesuvius Observatory in Naples who led the work. “It’s like a puzzle, in which all the pieces have to fit together.”
A volcanic collapse causes tremors
The eruption of Mount Vesuvius unfolded in phases, beginning in the late morning. Around 1 p.m., the volcano began spewing gas, ash and rock in an eruption column that stretched 18 miles high, creating a shower of pumice that buried the city and tore off roofs, triggering an initial wave of deaths. Those who survived this first phase may have tried to escape on foot, walking over the pumice layer, using branches as walking sticks. But a scalding “pyroclastic flow”—a fast-moving stream of ash, gas and rock fragments—killed the survivors, likely by suffocating them.
Pliny the Younger experienced the eruption as a teenager in Misenum, about 18 miles west of Vesuvius, and described the earthquakes the night after the eruption began as “so intense that everything seemed not only shaken but turned upside down.” He also recorded an earthquake at dawn—one that shook the ground so much that chariots that had been held in place with stones were shaken out of place.
But scientists didn’t discover direct evidence of earthquakes until they found walls that failed in ways inconsistent with volcanic explanations. Then they found the skeletons. The first individual’s body was riddled with fractures to the ribs, skull and pelvis. The second individual’s legs were buried under a fragment of wall, but he was also curled up on his left side with one hand protecting his head. Scientists think he may have been trying to protect himself.
The new discovery adds detail to the horror that unfolded on the morning of the eruption’s second day, after most of the magma had erupted. A caldera formed as part of the volcano collapsed, triggering a dangerous second phase of the eruption and an earthquake, Cioni said. The new evidence raises the possibility that earthquakes may have added to the danger, as ground shaking stressed the roofs loaded with rocks. with pumice stones.
Gianni Gallello, a distinguished researcher at the University of Valencia who specializes in using chemistry to understand the ancient past, said the study presents an intriguing variable to the dangers of that day in Pompeii that will add to the complex puzzle of reconstructing this tragic event. But he said remains a question whether these men died due to the collapse of the wall or were buried after having died from another cause.
“In science, there is never an end. We are continually improving and adding new information,” Gallello said. “This is the never-ending story.”
