Put on your serious hats, folks. Today’s story has a moral.
In April 2009, a 6.3 magnitude earthquake hit the city of L’Aquila in central Italy. With over 300 dead, hundreds more injured, and thousands of buildings damaged or destroyed, it was the worst earthquake to strike Italy in decades. And now a group of scientists are being blamed for it.
|The L'Aquila earthquake devastated |
several towns in 2009
For several months before the quake, the region had been experiencing small tremors, and a meeting was held to discuss whether or not there was cause for alarm. A panel of seven earthquake experts decided that these tremors were not unusual for the region, and stated that it was unlikely that a major quake was coming. The disaster occurred a week later, and now, Judge Giuseppe Romano Gargarella is ordering that the seven scientists be tried for manslaughter. The judge claims that the experts’ information was faulty and misleading, and that, had the scientists done a better job predicting the earthquake, an evacuation could have been planned, and lives could have been saved.
Back in March, I talked a bit about earthquakes, and I mentioned that we have yet to find a good way to predict them. Ask any seismologist and they’ll back me up. But don’t just take my word for it. Let’s talk about it. Let's learn.
Why are earthquakes so hard to predict?
First off, what makes the Earth quake? Well, the Earth’s crust is in constant motion. Different segments of the crust (plates!) are constantly sliding past or pushing against each other. The pressure of all this rock stressing and straining eventually results in a break. Part of the crust fractures, lots of energy is released, and the ground shakes. Ask Wiki about it.
Now, knowing how earthquakes happen gives us some predictive power. We know, for example, where earthquakes are most likely to occur, and often we can even guess at when a big quake might be coming. In this way, earthquakes can be forecasted, like the weather. The weatherman may say “This afternoon there’s a 30% chance of rain.” Earthquake forecasts are similar, but over a longer time scale. A seismologist might say “There’s a 50% chance that an earthquake of magnitude 7.0 or greater will occur in California before 2018.” It may seem vague, but at the moment, that’s the best we can do.
|This map shows the probability of earthquakes across the U.S.|
In order to predict a specific earthquake only weeks or days before it occurs, we would need a definite signal that the quake was coming. Lots of ideas have been proposed for this. Scientists often talk about foreshocks. A foreshock is a small quake that happens before a much larger quake. For example, you might get a series of 4.0 and 5.0 quakes for a couple weeks before a big 7.0 comes along. The small tremors occurring in Italy were foreshocks to the big L’Aquila quake. Some researchers think foreshocks might help predict big earthquakes before they happen. But there are problems. Sometimes a 7.0 comes out of nowhere with no foreshocks at all. Other times, you might get a bunch of 4.0s and 5.0s, but no big quake comes afterward. So how can you tell if your 5.0 is a foreshock or just a small earthquake? Well, usually, you don’t know until the 7.0 shows up. In the case of the L’Aquila quake, the scientists’ best guess was that the small tremors were not foreshocks, but just small quakes, which are fairly common in that region. Unfortunately, this time they were wrong.
Plenty of other “warning signs” have been proposed over the years. Some researchers think there are geothermal signals before a quake; others have looked into atmospheric warnings; I’m sure you’ve heard of animals acting strangely before an earthquake happens. But all of these “warnings” have been studied, and so far, none have been properly confirmed. Sometimes they seem to work, sometimes they don’t at all. And that’s not good enough. If Tokyo evacuated every time someone’s dog was acting oddly, you’d have a lot of wasted money and annoyed citizens.
The search for a warning sign is complicated further by the fact that every quake is different. An earthquake on the San Andreas Fault in California happens under very different conditions than one in the Appennes of Italy. Not to mention, earthquakes can affect each other in complex ways. There are a lot of obstacles to overcome before we can successfully make short-term predictions about earthquakes.
So, if we can’t predict earthquakes, what can we do?
Two things. First, we need to learn more. Of course, scientific research must continue if we’re going to find the solution to the earthquake problem, but the public needs to learn as well. People need to understand earthquakes and why they happen. And the L’Aquila case is a perfect example. The judge that has put these scientists on trial clearly doesn’t understand earthquake science. The scientists involved did the best they could with the tools they have, and blaming them for this disaster not only threatens to hinder earthquake research by compromising the jobs of seven scientists, but also threatens to further alienate the scientific community from the public.
Second, be prepared! We may not know what day exactly the next big earthquake will strike, but we know where it might be, and we can set up a time frame, and we can be ready. Cities in earthquake-prone areas from California to Mexico to Japan have set up systems to help warn and protect their citizens in case of a big quake. The USGS website includes a guide for earthquake preparation. Also, stay informed. The USGS site provides up-to-date info on earthquakes around the world. The site's really neat - you can get detailed info on earthquakes all over the globe. There’s even an app for that!
|The USGS website allows you to see up-to-date seismic activity across the globe!|
Hopefully, the charges against those scientists will eventually be dropped. Hopefully, researchers will find more accurate methods of predicting earthquakes in the near future. And hopefully, I've inspired you to learn a bit. Remember: science isn't perfect, but we're doing our best all the time. Bear with us. ...And please don't send us to jail.