How an Earthquake Works

Although current technology allows scientists to predict earthquakes right before or as they happen, the best defense against a trembler is to find a sturdy table, doorway or other safe location as soon as the first jolts hit. But that still does little to help our understanding on how a quake works. In order to better understand earthquakes, we need to look at how they tick, according to

The first thing to know about earthquakes is that as the fault moves, it radiates energy that translates into two types of waves. The first, called a P-wave, moves ahead of the second wave, called an S-wave. The P-wave causes an initial bump, but other than that does little else. The S-wave is what carries all the damaging energy as it plows through the crust. It is the P-wave that is initially detected by earthquake sensors, letting officials know that the more powerful S-wave is on the way. This doesn’t provide much preparation time, but it does allow officials to pinpoint where the quake happened, allowing emergency personnel to respond to the situation soon after it happens.

Even though current equipment can let citizens know within seconds that a quake is imminent, improvements must be made. For example, incorporating GPS data with the seismic readings could improve early warning systems. In fact, officials in California are working on an early warning system, called ShakeAlert and estimate it could be up and running by 2015. It would be one of the first systems like this in the U.S., which currently does not have an early warning system.

But all the early warning systems in the world won’t be able to warn those at or near the epicenter, as the P-wave will not have travelled far enough ahead of the S-wave to give a warning. That is when the old methods of taking cover at the first signs of an earthquake come into play.

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