Episode 3 - SHAKEALERT

The West Coast Earthquake Early Warning System

In this episode of The Deconstructed Podcast, we are answering a question from one of our listeners who heard about the release of the new Earthquake Early Warning (EEW) system, ShakeAlert LA. He wants to better understand how EEW systems work.

To get an answer for this intriguing topic, the Deconstructed Crew decided to interview Robert DeGroot, a scientist who works and the United States Geological Survey (USGS) and is part of the team developing ShakeAlert. If you live in an area that has earthquakes, this is an episode you don’t want to miss!

For starters: ShakeAlert is the Earthquake Early Warning system developed for the West Coast of the United States by USGS and a coalition of partners (if you want to know more check out the ShakeAlert website).

But what is an Earthquake Early Warning System? Like the name says, it is a system that can alert you that an earthquake is coming. It is important to clarify that this is not a prediction system. In fact, the alert can be sent out only after the first seismic waves reach the surface of the Earth.

How it works...


EEW systems are composed by three parts:

1. A network of sensors (seismometers) that detect the first earthquake waves when they reach the surface of the Earth;

2. Data processing centers which analyze the data from the sensors, identify earthquakes, and decide if an alert should be sent;

3. A distribution system that sends an earthquake alert to the population in the earthquake-affected area. The message could be sent through television, cell phone messages, apps, etc.  

Having a functional EEW in seismic regions is so important because this can literally save lives! And potentially, a lot of them. If you are alerted of the earthquake before it happens, you can take protective actions (duck, cover and hold); but also, this system can be used by industries for automatic responses. For example, trains could slow down, water valves could close, and PA systems in schools could go off.

Even if the benefits of this system are clear, this is a large and very complex system. And the most critical element to make this system work correctly is TIME. To be effective, an earthquake alert needs to reach people before the earthquake does, meaning: in a matter of SECONDS. And this is not easy because not only do earthquakes propagate very fast, but also a lot of people in the West Coast of the United states live very close to fault lines (if not on top of them). If the alert is not fast enough, the earthquake might get to you before the alert does.

At this point in the development of ShakeAlert, the first two components of the system (sensors and data processing center) are already very fast, and they can generate a message in few seconds. However, the “weak link” in this chain is the distribution system of ShakeAlert, which is still not fast enough. Another factor that makes ShakeAlert so complex is that it needs to consider not only the technical aspects, but also some psychological and sociological ones. For example: what does your cell phone do when it needs to give you an earthquake alert? This message needs to be easily recognizable, so you don’t have to waste time to get your phone out of your pocket.  

Most other Countries with active seismic regions started developing their earthquake early warning systems after major earthquakes in the 80s and 90s; the United States started recently in 2006. And because of this delay, we still don’t have a fully functional system able to alert the population. However, we are getting closer and closer! In fact, the first two parts of the system (the sensors and the data processing centers) are almost complete and can already generate an earthquake alert. However, the alert still cannot be distributed fast enough.

However, Bob and a lot of other incredibly smart people are working on this, so stay tuned!

Want to hear the latest news? Keep checking in with ShakeAlert’s news page.