Thursday, December 10, 2020

Earthquake Early Warning Apps

Having lived in California for most of my life, I’ve felt many earthquakes. Some have been larger than others, but they are all scary to me. Of all the natural disasters in the world, earthquakes are unique in that people have the least amount of time to take action when they occur. Even with the latest technology, early warning systems may give only a few seconds of advance notice before shaking is felt. I am aware of 2 apps that have this goal in mind.

The ShakeAlertLA app is provided by the Office of Los Angeles Mayor Eric Garcetti, the Information Technology Agency and the Department of Emergency Management. It has been made possible by support from the Annenberg Foundation and the Mayor’s Fund for Los Angeles. ShakeAlertLA is an official pilot in partnership with the U.S. Geological Survey. I previously wrote about it here, and more information is available at the ShakeAlert website.

The MyShake app is discussed on the Earthquake Warning California website. Earthquake Warning California is the country’s first publicly available, statewide warning system that could give California residents crucial seconds to take cover before shaking is felt. MyShake delivers ShakeAlert across California.

How does early warning work? When an earthquake happens, a rupturing fault sends out different types of waves. The first wave felt is the fast-moving P-wave. The slower-moving S-waves arrive later causing the most damage. Sensors detect the P-wave and immediately transmit data to an earthquake alert center where the location and size of the quake are determined and updated as more data become available. A message from the alert center is immediately transmitted to your computer or mobile phone with data on the expected intensity and arrival time of shaking at your location. Specifically, when your phone is stationary, MyShake is ready to collect data from its motion sensors. It then decides which motion is produced by earthquakes and which isn’t. So basically, when you install one of these apps, your phone becomes part of a seismic network for earthquake early warning, as described in this publication.

Both ShakeAlertLA and MyShake provided information about how to prepare for earthquakes and what to do during and after an earthquake. Both apps also provide maps of earthquakes, but the MyShake app shows and allows users to explore far more earthquakes, probably because it earthquakes of lower intensity. MyShake also has interactive features that allow the public (referred to as “citizen scientists”) to report their experiences. MyShake also lets users configure notifications about earthquake events—simply enter a location, radius, and intensity. Finally, MyShake has sensor that is fun to play with. It records movement along the X, Y, and Z axes and can display the information in a graph in the app (below) as well as allow users to record and export the raw data.

In summary, I find MyShake to have more robust features than ShakeAlertLA. Regardless of your choice, download one of them today. Even if it doesn’t save your life, you’ll be contributing to the advancement of earthquake early warning science.

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