It is first important to note that earthquake early warning (EEW) is not earthquake prediction. EEW systems work because the speed of the earthquake’s P-waves is almost twice as fast as the earthquake’s more damaging S-waves, and because the speed of modern telecommunications is many times faster than the speed of seismic waves. This means that an earthquake can be detected by local seismic networks, processed, and alerted on before damaging shaking reaches many locations.
ShakeAlert uses real-time seismic data from local Regional Seismic Networks, such as the SCSN, to rapidly detect the early ground motions of an earthquake in progress. Once ground motions are detected, the data are immediately transmitted to a ShakeAlert processing center, where a complex set of algorithms automatically estimate the earthquake’s location, magnitude, and expected shaking intensity distribution. If the estimated earthquake information meets a set of predetermined criteria, the USGS issues automatic messages to its Technical Partners who rapidly alert people and trigger automated actions. If the initial shaking begins far enough away, the warning time could range from a few seconds to tens of seconds.
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Where can I learn more?
Visit shakealert.org for more on current efforts, funding and research partners, partnership opportunities, and a comprehensive overview of the West Coast implementation of the ShakeAlert Earthquake Early Warning System.
Information pertaining to the development and implementation of the ShakeAlert® Earthquake Early Warning System sourced from shakealert.org. Accessed: March 22, 2023.
How can I get ShakeAlert EEW on my phone?
If you are in California, visit the official Earthquake Warning California webpage where you can get more California specific resources, downloads, and information all in one place. Visit Earthquake Warning California or directly download and use ShakeAlert-powered EEW mobile phone apps by visiting the Google Play or App Store and searching for “MyShake” or “ShakeReadySD”. All apps are available for free and can be easily downloaded and installed on Android and iOS devices. Once the app is installed, you can enable push notifications to receive early warning alerts when an earthquake above a set magnitude is detected in your area. The MyShake app is also available in Oregon and Washington.
Android phones have ShakeAlert-powered Alerts built into the operating system. Android operating system alerts are available in California, Oregon, and Washington, and no download is necessary.
ShakeAlert-powered Alerts are also issued via the Wireless Emergency Alert (WEA) system. WEA alerts can reach most modern mobile phones in California, Oregon, and Washington. However, WEA alerts may not be as fast as alerts delivered through other methods, so downloading mobile apps and/or using Android operating system alerts is encouraged.
