Earthquake Early Alert Systems

Earthquake Early Alert Systems: Why Do We Need Them? Do They Even Work?

A Seismological Snafu

In 2009, six Italian seismologists and one official were convicted of manslaughter for not predicting an earthquake that hit the town of L’Aquila and killed over three hundred people. The ruling was later appealed and the verdict overturned. The appeal claimed that it was impossible for even the most experience seismologists to be able to accurately predict an earthquake. While this fact still remains so, science is getting closer and closer with each new advancement in earthquake detection technology.

Detecting Warning Waves

Though there may not be a way as of yet to tell when a tectonic plate will shift and cause a temblor, new detection systems that are now in operation have the ability to sense seismic waves. These waves are known as P waves and S waves – or primary and secondary waves, respectively. What this means is that the primary waves, which come from the shaking at the beginning of a quake, can be detected before the secondary waves begin, those waves being what carry the bulk of the seismic energy (what we feel) and what do the most damage in a quake. Between these two occurrences of waves, there are potentially precious seconds (up to even minutes in some cases and locations) during which people can take the duck, cover, and hold position or otherwise prepare for the shaking to start. The advantage of being able to take even the shortest time to prepare could mean the difference between life and death.

More Uses

Not only can individuals benefit from the use of an early warning system, but so can commercial business owners and metropolitan cities that are earthquake-prone. Take San Francisco, for example. There are over a hundred sirens set up around the city in order to alert residents of an emergency situation. Should an early detection system be set up and linked to these sirens, it could save a great number of lives. People would be able to stop what they were doing, wherever they were, and take adequate cover before the shaking began. This would be especially useful to alert doctors performing surgery to halt their work, firefighters whose firehouse doors might otherwise get stuck closed, and those who operate and ride metropolitan transit systems to avoid a potential derailment. There is really a countless variety of ways in which an early warning system may be of use to individuals as well as masses of people.

Earthquake Early Warning Is Here

That technology is no longer theoretical. California now operates ShakeAlert, the first statewide earthquake early warning system in the United States. Built on a dense network of seismic sensors managed by the U.S. Geological Survey, it detects the fast-moving P-waves at the start of a quake and pushes alerts to the public for free through the MyShake app, Wireless Emergency Alerts, and the earthquake warnings built into Android phones. Depending on how far you are from the epicenter, those alerts can arrive several seconds to tens of seconds before strong shaking reaches you, which is often enough time to drop, cover, and hold on. While we still cannot predict the time, place, and whereabouts of the oft-mythologized “big one”, we might just be able to pick up on its preliminary waves and be able to take cover when it strikes.