In the summer of 79 A.D., Mount Vesuvius erupted, obliterating the seaside resort of Pompeii. Volcanic ash covered everything, preserving evidence of the disaster for nearly two millennia. The story endures too, in accounts by eyewitness Pliny the Younger, who viewed the eruption from a nearby town, and in books, TV movies and films inspired by the catastrophe.

Director Paul W.S. Anderson’s “Pompeii” (opening Feb. 21) is the latest in the genre, focusing on a fictional love story to recount the explosive event, while endeavoring to recreate an ancient world as precisely as possible. His CGI Vesuvius erupts spectacularly, but how accurate is it? Is “Pompeii” true to history? And could this kind of cataclysmic eruption happen again there — or elsewhere on Earth? For answers, we turned to two experts, Sarah K. Yeomans, professor of Roman archeology at West Virginia University, and Dr. Rosaly Lopes, volcanologist and senior research scientist and manager of the Planetary Science Section at the Jet Propulsion Laboratory.

Yeomans, who has taken students to Pompeii many times over the last decade, characterizes the ruins there as uniquely “flash frozen in time. When we visit this site we get a real sense of how Romans lived and the things that were important to them. It’s the best insight we have into this ancient culture,” she says, which coupled with a morbid curiosity about devastating disasters, is what makes it so eternally fascinating.

“One of the things I really enjoyed was the way Paul Anderson reconstructed the site. He clearly has been there, had done the photography. For example the streets of Pompeii had [raised] stones that people would walk across to avoid mud, sludge and water,” she points out. “The way he reconstructed the houses was really well done, right down to graffiti inscribes on the walls.” The latter was often political or sexual in nature, but the phallic images had a purpose, “what we call an apotropaic function,” Yeomans explains. “They would put images of the phallus next to the doorways. It was a symbol to ward off evil and bad luck. Not all of them did this, but it does account for some of the ubiquity of phallic images.”

Visually, Yeomans believes the film “did a nice job with the layout of the city, with respect to where the amphitheater is and respect to other buildings,” and she appreciated its portrayal of the Pompeiian resentment of Rome, which had annexed it 150 years before. But she sees artistic license at play in the depiction of the volcanic eruption. “There was never a lava flow and these firebombs you see launching out of the volcano. That did not happen in this particular type of eruption. But it’s a movie, not a documentary,” she adds.

What killed most the population was a combination of heat and ash. “The most deadly phase of the eruption is what’s called a pyroclastic flow — basically super-heated mud that comes racing down at about 80 mph and that kills people pretty much immediately. Most of the people died of heat shock,” says Yeomans. "Nevertheless, there were a few who lived.”

“There is plenty of evidence that people did survive. We have inscriptions in other towns that were made by survivors of Pompeii who had relocated. We know that many people left when the earthquakes began. There are tunnels in Pompeii, evidence that people may have come back to tunnel down and retrieve some of their possessions.”

Yeomans, who “fell in love with Roman archaeology in my junior year in college” while studying abroad in the Roman ruins-laden region of southern France, says that Pompeii’s ruins are in a vulnerable state due to excavation and tourist traffic, “a pretty large concern at the moment. There have been several recent collapses of houses at the site. They’ve really slowed down on the granting of excavation permits and limit tourist traffic. There’s a great deal of the site that tourists are not allowed access to. The focus is on conserving what’s been excavated.”

Will a volcano catch us by surprise?

Also of concern is the possibility, however remote, that Mount Vesuvius — an active volcano — might erupt again. If it did, “It would be equally as dangerous and would affect many more people because now the area is much more populated. We have better technology for evacuation and detection now, though,” Yeomans points out. “Volcanoes are not going to catch us by surprise.” She explains that earthquakes precede volcanic eruptions, “which is what happened with Vesuvius in AD 79. The region is volcanic, and the Romans were used to seismic activity, but there’s no evidence to suggest that they connected the two. They didn’t realize that it was a warning sign of a coming eruption.”

According to Lopes, “Vesuvius has not erupted since 1944, and that was not a violent eruption. Not all eruptions of Vesuvius are as violent as the 79 A.D. eruption was; most are not. It could erupt again. The most violent eruptions of Vesuvius tend to occur after the volcano has rested for several hundred years. Vesuvius is very well monitored, so we will have some warning.”

Rosaly Lopes in Vanuatu

Dr. Rosaly Lopes in Vanuatu (Photo courtesy NASA/JPL)

Globally, “There are many other volcanoes in the world that have the potential to have violent eruptions such as the 79 A.D. one. Mount St. Helens in 1980 was a violent explosive eruption,” she offers as an example. “There are about 600 volcanoes on land considered active, meaning they have been active in historic times and we think they are likely to erupt again. There are many underwater volcanoes along the spreading ridges. As for volcanoes in the U.S., Kilauea erupts often — and it has been active for decades — but not in a violent, explosive way. The most hazardous volcano in the U.S. is considered to be Mount Rainier. This means it could erupt in the near future and has the potential to be very dangerous — it could erupt in an explosive way like St. Helens in 1980. What makes it more dangerous is that it has glaciers at the top, and even a not-very-violent eruption could cause ice to melt, creating mudflows, which are very destructive.”

Lopes, who holds a degree in astronomy from the University of London, got into volcanology via a planetary geology course (when the professor missed class to cover a Mount Etna eruption; “I thought that sounded really exciting, and decided that I wanted to do that too.”) She says that in analyzing hazardous volcanoes, modern scientists “look at frequency of eruptions in the past, and how likely one is to happen again in the next few decades.”

For example, Yellowstone National Park is a hotbed of volcanic activity. “Yellowstone has had enormous eruptions in the past, it is the largest volcanic caldera on Earth. Calderas are formed by collapse following very violent eruptions. Yellowstone's violent eruptions last occurred hundreds of thousands of years ago. Although its eruptions could potentially be far more devastating than Mount Rainier's, they are less likely to happen in the near future,” she says. Consider yourself reassured. Or forewarned.

Sarah K. Yeomans with students at Pompeii. Mount Vesuvius is in the background. (Photo: Alyssa Beall)

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