The Earthquake early-warning system called ShakeAlert is now available to residents of California, Oregon and Washington after 15 years of planning and development. It reaches 50 million people in the most earthquake-prone region in the U.S. People in these three states can now receive alerts from a wireless emergency alert system, third-party phone apps, and other technologies. Hence, the system will give them precious seconds of warning before an earthquake hits.
The ShakeAlert system aims to facilitate the delivery of public alerts of potentially damaging earthquakes and provide warning parameter data to government agencies and private users on a region-by-region basis.
The ShakeAlert system relies on sensor data from the USGS Advanced National Seismic System (ANSS). ANSS is a United States Geological Survey (USGS)-facilitated collection of regional earthquake monitoring networks operated by partner universities and state geological surveys on the West Coast and throughout the nation.
The mechanisms of the ShakeAlert system include during an earthquake, a rupturing fault sends out different types of waves. The fast-moving Primary (P)-wave is first to arrive, followed by the slower Secondary (S)-wave and later-arriving surface waves. Sensors then detect the P-wave and immediately transmit data to a ShakeAlert processing centre where the location, size, and estimated shaking of the quake are determined.
If the earthquake fits the right profile a ShakeAlert message is issued by the USGS. A shake alert message is then picked up by delivery partners (such as a transportation agency) that could be used to produce an alert to notify people to take protective action such as Drop, Cover, and Hold On and/or trigger an automated action such as slowing a train.
In addition to supporting public alerts to mobile phones, ShakeAlert system data has, since late 2018, been used to develop applications that trigger automated actions. Automatic actions can be used to prevent derailments, open firehouse doors so they do not jam shut and close valves to protect water and gas systems.
USGS works closely with ANSS partners and state emergency management agencies on the system’s development as well as public communication, education and outreach. ShakeAlert is a new ANSS tool in the USGS risk reduction toolbox.
Associate Director of the USGS said that the science of USGS is the backbone of hazard assessment, notification, and response capabilities for communities nationwide so they can plan for, and bounce back from, natural disasters.
Systems powered by ShakeAlert can turn mere seconds into opportunities for people to take life-saving protective actions or for applications to trigger automated actions that protect critical infrastructure. An effort like this takes the dedication, ingenuity and hard work of dozens of partners with the same vision. USGS is proud to have been part of a collaborative team that made this robust public safety system available for millions of citizens on the West Coast.
Studies in Washington, Oregon, and California have shown that the warning time would range from seconds to tens of seconds. ShakeAlert can give enough time to slow trains and taxiing planes, to prevent cars from entering bridges and tunnels, to move away from dangerous machines or chemicals in work environments and to take cover under a desk, or to automatically shut down and isolate industrial systems.
In addition to these Phase 1 implementations, technical improvements to the ShakeAlert system are also part of the story. The sensor network has reached target density in the Los Angeles, San Francisco Bay and Seattle metro regions and version 2.0 of the ShakeAlert production system has been deployed.
This version of the ShakeAlert system produces both point source and line source earthquake solutions. It has added ground motion estimation products, and the number of false and missed events has been reduced. ShakeAlert system version 2.0 has also satisfied government cybersecurity requirements and includes improved operational procedures.
