Bad Geology Movies: Volcano, 1997

The first in a series of posts about what’s wrong in movies with geology-related themes.



Tommy Lee Jones and Anne Heche


Premise: What if a volcano appeared and started erupting under a populated area like Los Angeles?


I guess one could suppose that because there’s a plate tectonic boundary (the San Andreas fault) there along the margin of North America that a volcano might arise. There’s volcanoes all around the margins of the Pacific Ocean – along plate boundaries – which are given the apt name of “Ring of Fire.” The Cascade Mountain Range, including Mount Rainier and Mount Saint Helens are such volcanoes.

One problem: These volcanoes occur along subduction zones, where basically the ocean floor is being drawn under the larger continents. The Pacific Plate (under the Pacific ocean) is being subducted under Alaska (the Aleutian Islands) and under Japan and in lots of other places. Under the Cascades, the Juan de Fuca Plate is being subducted. The Nazca Plate is being subducted under South America, resulting in all the volcanoes associated with the Andes.

Alas, subduction is NOT occurring in California. There, the Pacific Plate is moving northward with respect to the continent of North America. The San Andreas fault is what is called a “transform” fault, where the rocks slide past each other, not where some rocks override others (like in a subduction zone). Because of this, we can’t expect huge volcanoes like we see in the Cascades. Usually, if there are volcanoes along transform faults, they’re pretty small. They’re not completely impossible, so the possibility exists.

Of course, the explanation provided by the geologist in the movie, Dr. Amy Barnes (played by Anne Heche) is not like this at all. And in the end, they get a new mountain out of the deal, which is highly unlikely. We’ll just ignore that…

There are lots of things that bug me about this movie, from the stance of a geologist – the likelihood of a volcano in LA aside.

1) I really don’t think the K-rails are going to do much to block flowing lava. And dousing it with water? Well, I guess they do these sorts of things elsewhere with some success. But the movie makes it out like they stopped the flow of lava completely. I suspect that in the real world, the best outcome in such a situation is a diversion of the flow. That stuff’s hot! And there’s a lot of it! Let’s send it somewhere else and we’ll be OK – which is what they did in the end. (And how come no one except for the geologists had any idea what ‘lava’ was?)

2) A greater problem is that they should have all died of massive bleeding in the lungs before they even had a chance to try to block the flow of lava. Ash is basically fine shards of glass. No one was wearing masks, so they were basically inhaling glass. For hours. Not one cough. No sneezing. No gasping. Right.

3) The news report at the end made me facepalm. ‘The volcano is shutting down,’ the reporter said. ‘The lava is subsiding.’ Volcanoes don’t just ‘shut down,’ and lava doesn’t ‘subside.’ Once the lava’s on the ground, it’s solid. There is no subsiding. Maybe they were referring to magma deep within the Earth. Anyway, the idea that a volcano can just turn on and off like that is extremely sketchy, though mightily convenient for a movie.

4) Dr. Barnes mentions that the bible verse Matthew 7:26, “And every one that heareth these sayings of mine, and doeth them not, shall be likened unto a foolish man, which built his house upon the sand,” is very popular among geologists. Strangely, I’ve never heard that one before. Just saying.

I won’t go into the other gripes and hilarious things that happen in the movie, as they are not related to geology. I will say that the movie was clearly pre-9-11, and I loved the giant cell phones. I did get into the story sufficiently that I was engaged with the main characters and glad that everyone came out OK. It’s not the worst ‘bad geology movie’ I’ve ever seen.

1 thought on “Bad Geology Movies: Volcano, 1997

  1. I even am amused and I’m just a regular joe. When I was in Hawaii we had to observe steam coming out of vents from hundreds of years away. The movie made it look like you could stand inches from lava and breath in a the poisonous gases and ash without consequences. Hollywood!

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