Paul W.S. Anderson's Pompeii may be more fiction than fact, but real aspects about Mount Vesuvius' eruption depicted in his latest movie will impress even the most skeptical scientist. If you don't believe me, take Dr. Rosaly M. Lopes-Gautier and Sarah K. Yeomans' word for it. They didn't work on Anderson's movie, but they are an authority on the world he was trying to create.
Dr. Lopes-Gautier is a member of the United Kingdom's Volcanic Eruption Surveillance team, a visiting researcher at the Mt. Vesuvius volcanological observatory in Naples, Italy, and she's visited over 50 active volcanoes worldwide. Professor Yeomans is an archaeologist focusing on the Roman period, specializing on the explosion and the aftermath of the eruption in 29 AD. Needless to say, they had a lot of thoughts on the reality of what happened in Pompeii and Mount Vesuvius' eruption.
Here are 11 dramatic facts they taught me about Pompeii, as well as an extended conversation below about what the movie didn't address.
My Pompeii facts are mostly from the eighth grade. What did you guys think of the movie, the representation of this city port, and the eruption?
Yeomans: In the way that Paul Anderson recreated this landscape, I think they did a wonderful job. You can tell that he really paid a great deal of attention to the archaeological site. There's certain details in the movie that made me smile - like those protruding blocks in the middle of the roads. They were there and are there today, so that people could walk across them when it rained and avoid walking through the mud.
Lopes-Gautier: In terms of the volcanic eruption, the sequence of events was very good. There's a misconception that the volcano just went bang and caught everybody by surprise. There were precursors in the movie that they show like a lot of earthquakes. There was an explosion, but the first explosion didn't create an immediate pyroclastic flow that killed people. It wasn't just very compressed. The eruption from beginning to end lasted over 24 hours. They did a great job with the explosion cloud and the pyroclastic flows. They did use artistic license in certain places, but I think everyone knows this is a movie and not a documentary.
One of the things that the movie doesn't acknowledge is that Pompeii suffered from an earthquake in 62 AD. Are there any records of what people thought about that and how that influenced people's idea of an eruption?
Yeomans: That's a great question. Yes, in fact, it's very well documented because it was such a severe earthquake that the Emperor Nero released public funds to help with the repairs and archaeologically we can tell that this damage happened and that even up until the eruption in 79 that people were repairing their homes. There may have been ensuing earthquakes and tremors in the interim, but they were used to this seismic activity and repairing and reinforcing their structures and homes. It was part of their ethos and part how they understood their region. There is no evidence to suggest they connected the earthquakes to an active volcano.
Lopes-Gautier: In fact, Vesuvius had not been active for a very long time, hundreds of years or maybe over a thousand years. They didn't realize it was an active volcano.
Were there supernatural explanations?
Yeomans: There is no evidence to suggest that the Romans felt this was a wrath of the gods. They had a very different relationship with their gods than people do in the Judeo-Christian world. Even though Vulcan was the volcano god, he was the armorer, and volcanoes according to mythology were the forges of Vulcan, there's no evidence to suggest that the educated and elite of Roman society doing all of the writing attributed this to a supernatural power or event. They understood it was part of the natural world even though they couldn't explain the mechanics of it.
One of the things we see in movies is ash falling like light snowfall. But it seems like there would actually be a lot of ash.
Lopes-Gautier: There would be a lot. And there would be a lot of pumice-fall, which they didn't show in the movie, which would be a lot of pellets that are light in color. It wasn't exactly the way a volcanologist would have constructed it, but with some reconstructions I would have probably done the same.
Yeomans: When you go through Pompeii, those pellets she's talking about, that's what you're walking on when your in the sites that haven't been excavated yet. It's pumice gravel. And the ash cloud, Cassius Dio, who's a Roman writer who wrote about it about 100 years later talked about how the skies over Rome darkened for several days even though the majority of the ash cloud went to the southwest. It was still vast enough that it blocked out the sun in Rome, which was 90 kilometers to the north.
One of the things that makes Pompeii such an amazing place to visit is the preserved bodies. Can you talk about how that happens?
Yeomans: What you're looking at are not bodies. They are plaster casts that are made by archaeologists because after all of this pumice, mud, and ash has covered the city, everything that's organic in it decays. Not just people - animals, trees, anything made of wood. In the 18th Century, when they accidentally found this place, someone hit on the idea that if they started to break into a cavity and just filled it with plaster and waited for it to harden before they took away the material around it, they would have a perfect cast of whatever had been in that space. The bones remain in the cast.
Lopes-Gautier: It was a mystery about how the bodies looked like bodies for a long time. You can still see the facial expressions and even see the lines of cloth on their clothes. Herculaneum is another city that was destroyed by Vesuvius that was closer to the volcano. The bodies there were not so well preserved. The first pyroclastic flow hit Herculaneum and it was much hotter. The pyroclastic flow that hit Pompeii wasn't as hot because it had a few miles to travel so that the people still died from heat shock. It was still around 500 degrees.
Pompeii was a port city, but now it's not even on the coast. How does that happen?
Lopes-Gautier: The quantity of material that's deposited can extend the coastline. One example that you see today that's a different eruption is in Hawaii. The coastline of Hawaii is actually being extended by lava flows.
The biggest volcano in the United States is actually underground at Yellowstone, which is described as a super-volcano.
Lopes-Gautier: When we're talking about how dangerous a volcano is, we have to look at several factors like how likely it is to erupt in the near future and how large the eruption is likely to be. Yellowstone could be a totally devastating eruption. Like, we're talking really, really major. It would cause climate change and destroy vast amounts of land in the US, but Yellowstone hasn't erupted for hundreds of thousands of years. The chance that it might have the same time of eruption happening a year from now or five years from now are not that high. The most hazardous volcano in the United States is considered to be Mount Rainier because it's near populated centers, it erupts much more often, and it has glaciers. When magma moves up, even if it's not huge, it can melt the glaciers, and then that melts with the ash and comes down as mudflows.