Bad Geology Movies: Earthquake, 1974 – can we even predict earthquakes?



Charlton Heston, Ava Gardner

Premise: What would happen if a massive, magnitude 7.0 or greater, earthquake hit Los Angeles?

I bought this movie for cheap somewhere, assuming that it would be an excellent “Bad Geology Movie.” I couldn’t imagine that Hollywood would get an earthquake right.

It turns out that this movie is a typical 1970’s disaster film with an all-star ensemble cast. There was very little attempt at real science in the movie, so I don’t have a lot to say.

I do have one major point to make about this film, regarding the prediction of earthquakes. The film opens with a graduate student accurately predicting two foreshocks of the massive quake that takes out L.A. In fact, the student predicts the enormous quake as well. By some strange miracle, the mayor of L.A. is willing to mobilize the National Guard based on this prediction. The earthquake happens and chaos ensues.

This would be an amazing scenario. It would be fantastic if we could accurately predict earthquakes. But the fact is that we cannot. Not even close.

What’s worse, is that because of the political climate, even if a scientist thought he or she could predict earthquakes, they would be reluctant to say anything. It’s a miserable situation.

The characters in the film note that an incorrect prediction could be disastrous to people’s faith in science. You don’t want to cry wolf, as it were. Equally, a prediction of no earthquake, followed by a violent quake would be just as bad. People would demand to know why they weren’t warned. So what do we, as scientists, do?

For one thing, we always include probabilities on our predictions. Perhaps we only raise warnings if we think there’s a greater than 50% chance that an earthquake will happen. But even if the probability is only 10%, a quake could still happen. What then?

We also have to consider the evidence that we’re using to make these predictions. Often they’re based on historic data (how often have earthquakes happened in the past) with a little bit of new geophysical data (like sensitive GPS systems). We really don’t have enough adequate data at this point to make accurate predictions at all.

Still, people are rational, right? They understand that such predictions are impossible, right? We like to think that, but the truth is, most people don’t understand this. And the likelihood that people will be sympathetic to the plight of the scientist after a huge, unpredicted earthquake is pretty small.

Such is what happened in 2009 near L’Aquila, Italy. Italy is a tectonically active region, frequently hit with small earthquakes. There were a few strong earthquakes leading up to a magnitude 6.3 quake that hit on April 6th of that year. The town of L’Aquila was leveled and 309 people died.

Though there had been strong foreshocks in the area prior to the main quake, local geoscientists contended that the chances for a major quake were small, and the town was warned but not evacuated. After the earthquake, 6 geologists and 1 government official were put on trial for involuntary manslaughter, for not having adequately warned the citizens of L’Aquila, which resulted in the large death toll. In October of 2012, all seven men were sentenced to six years in prison.

Well, if this is what happens when you try to make any predictions in geology or the earth sciences, then I’m going to stay mum if there’s been any natural disasters. When Hurricane Sandy hit, I got a call from a local reporter who wondered if I would comment about how the hurricane related to global warming. I said no, in part because I didn’t really feel qualified to do so, but also because I don’t want to be held liable for making an incorrect prediction. It seems ridiculous, but it’s true.

I didn’t sign on to be a scientist to be held accountable for predicting earthquakes or hurricanes. I signed on so I could learn more about our world – with the hope that what I learn might just benefit others in unexpected ways. I’m certain that’s how those geoscientists in Italy felt as well. They were just doing their job to the best of their ability with the resources and data they were provided.

I think this whole episode has given many scientists pause to think about what they should or should not say publicly. I know I’m not alone.

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