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August 25, 2022

Over 50 million people in Washington, Oregon, and California can take protective actions prior to feeling shaking from an earthquake.  

In the time it takes you to read this sentence, you could Drop, Cover, and Hold On – important steps to protect yourself during an earthquake.  

Seconds of warning before earthquake shaking arrives can give you time to get into a safe position and allow facilities to trigger automated safety actions. A hospital could safely shut down an MRI scan, a public address (PA) system in a school could be activated, and a transit system could slow a train. 

The U.S. Geological Survey-managed ShakeAlert® Earthquake Early Warning System is designed to provide those useful seconds of warning. The ShakeAlert System is a partnership with state and federal agencies, universities, and private funders across the West Coast and uses earthquake science and technology to quickly detect significant quakes.  

If an earthquake meets the right profile, the USGS issues a data package called a “ShakeAlert Message.” USGS-licensed Technical Partners use this data to deliver ShakeAlert-powered alerts that could reach people and trigger automated systems seconds before earthquake shaking arrives.   

Nearly half of the U.S. population lives in areas of significant seismic risk, with most earthquakes occurring on the West Coast. The western United States lies along the boundaries of major tectonic plates that make up Earth’s crust—the North American Plate and the ocean plates to the west. These plates are moving against each other, deforming the crust along many faults like the San Andreas. 

Whether you get a ShakeAlert-powered alert on your phone, hear an alert on a PA system, or notice the train you’re riding automatically slowing down, you're experiencing different ways the ShakeAlert System is keeping you safe during earthquakes. 

How does it all work? 

The ShakeAlert System first detects ground motion from an earthquake by using a growing network of over 1,300 seismic sensors installed across the West Coast. The goal is to have 1,675 stations contributing to the System by the end of 2025. 

Ground motion data is sent to a processing center that estimates the location, magnitude, and shaking intensity of the earthquake in seconds. If it’s large enough to meet USGS alerting thresholds in magnitude (an absolute value) and shaking intensity (a relative value that depends on how close you are to the epicenter, or the location where the earthquake starts), USGS issues a “ShakeAlert Message” that gets transmitted to USGS-licensed Alert Delivery Partners who deliver alerts to people or trigger automated actions.  

How much warning you get, and if you get an alert, depends on several factors, including how far you are from the epicenter. Using USGS alert delivery guidelines, ShakeAlert Technical Partners set their own alerting thresholds, appropriate to the application.   

an infographic that moves from left to right, showing how the shakealert system detects and delivers alerts
  • A ShakeAlert Message is an early warning from a network system that detects significant earthquakes quickly enough so that alerts can be delivered to people and automated systems potentially seconds before shaking arrives. ShakeAlert Messages are a product of the Advanced National Seismic System (ANSS).  
  • ShakeAlert can protect people and infrastructure by triggering automatic actions like slowing down trains to prevent derailments, opening firehouse doors so they don’t jam shut, and closing valves to protect water systems.  

Getting an alert on your phone 

At 5 p.m. on September 20, 2021*, Robert de Groot noticed a bright white text box pop up on his phone.  

Earthquake Detected!  

Drop, Cover, Hold On. 

Protect Yourself. 

-USGS ShakeAlert 

He had gotten a Wireless Emergency Alert (similar to an AMBER Alert), delivered by FEMA’s Integrated Public Alert and Warning System. With this alert, de Groot, a member of the ShakeAlert System operations team with the USGS, was able to safely get underneath a sturdy desk and brace for potential shaking.  

“All People who live in and visit California, Oregon, and Washington now have access to ShakeAlert-powered earthquake early warning alerts – a critical new tool that anyone can add to their earthquake preparedness toolbox,” de Groot said.  

There are several ways to get ShakeAlert-powered alerts on a cell phone.  

  • Wireless Emergency Alert system: a public safety system that allows people who own compatible mobile devices to receive geographically targeted, text-like messages alerting them of impending shaking from a nearby earthquake. These alerts are currently available in California, Oregon, and Washington. Older phones may not be WEA capable, and some cell phone models require you to enable WEAs

  • Google: an integrated ShakeAlert-powered earthquake alert feature that is part of the Android Operating System. This service is available in California, Oregon, and Washington on cell phones using the Android operating system. 

  • MyShakeTM: an app developed by UC Berkeley and sponsored by the California Governor’s Office of Emergency Services (Cal OES). MyShake is available for free in the Apple iTunes and Google Play stores. MyShake is currently operating in California, Oregon, and Washington. 

  • ShakeReadySD: a component of the San Diego County Emergency app that provides ShakeAlert-powered Earthquake Early Warning alerts. ShakeReadySD only delivers alerts to phones in California. SD Emergency can be downloaded for free on the Apple iTunes and Google Play stores. 

  • QuakeAlertUSA: an app created by Early Warning Labs, LLC in collaboration with state and federal government agencies and academia. QuakeAlertUSA is available for free on the Apple iTunes and Google Play stores and is currently operating in California and Oregon. 

Getting an alert in a facility powered by ShakeAlert 

Inside Stanwood Elementary School in Washington State, there’s a box that is attached to the wall. Inside this box is a device installed by Varius, Inc. that is ready to receive ShakeAlert Messages to protect students and staff in 13 schools and buildings in the Stanwood Camano School District. When the ShakeAlert System detects a potentially damaging earthquake, the devices are ready to deliver a verbal warning through its PA system to drop, cover, and hold on.  

The Stanwood Camano School District isn’t alone in being connected to the ShakeAlert System. Here are some other partners that are also protected by ShakeAlert. 

  • The Los Angeles Metropolitan Transportation Authority (LA Metro) provides alerts to employees that an earthquake is occurring, and shaking is expected. The agency’s system send alerts that say, “Earthquake, earthquake, earthquake, shaking expected,” to prompt operations staff to start earthquake response procedures to secure people and property. 

  • Providence Medford Medical Center in Oregon is fully integrated with the ShakeAlert system. In the event of a major earthquake, the hospital operator receives a ShakeAlert-powered notification. The caregiver verifies the alert and then makes an overhead announcement: “Earthquake alert – Drop, Cover, Hold On.”  

  • The Santa Monica Library in southern California uses overhead speakers to alert patrons and staff to drop, cover, and hold on before shaking arrives.  

  • The Allen Brain Institute in Seattle, Washington provides alerts to employees on their computer screens.  

Early Warning Labs, a company based in Santa Monica, California, links end-users to the ShakeAlert System. It has helped various organizations around Los Angeles become powered by ShakeAlert, including LA Metro, Cedars-Sinai Medical Center, NBC Universal film studios, Santa Monica College, Los Angeles City Hall, and more.  

Staying safe with automated actions powered by ShakeAlert 

In the early hours of January 17, 1994, a magnitude 6.7 earthquake hit Los Angeles. What came to be known as the Northridge earthquake plunged the San Fernando Valley into darkness. Transformers exploded, power went out, and fires lit the sky. 

Local fire stations also lost power, trapping fire trucks inside the station. To help prepare for future earthquakes, the Menlo Park Fire Protection District in Northern California, working with SkyAlert USA, is powered by ShakeAlert. The system alerts firefighters that an earthquake is occurring and automatically opens fire station doors, turns on lights, and turns off gas appliances. 

Automated actions can help save life and property. Here are some partners who are part of the ShakeAlert System. 

  • The San Francisco Bay Area Rapid Transit District also known as BART, was the first transit agency in the nation to adopt an earthquake early warning system just over five years ago but has been working with USGS on earthquake early warning for over a decade. Its pioneering system powered by ShakeAlert protects riders and infrastructure by triggering automated actions, like slowing trains to prevent them from sliding off the rails during an earthquake.  

  • The Southern California Regional Rail Authority (Metrolink) adopted a new technology that uses ShakeAlert data to automatically apply the brakes to safely slow trains when an earthquake occurs.  

  • The City of Grants Pass, Public Works Department in Oregon works with ShakeAlert partner RH2 to close valves at water reservoirs and shuts off waterways when an earthquake is detected to prevent water loss from pipes that might burst during shaking. 

What powers ShakeAlert 

field engineers with the Pacific Northwest Seismic Network team at the University of Washington, install seismographs
Field engineers with the Pacific Northwest Seismic Network team at the University of Washington, install earthquake monitoring equipment on the slopes of Mount St. Helens, with Mount Hood in the distance.

ShakeAlert relies on sensor data from the Advanced National Seismic System (ANSS), which includes a robust network of seismometers across the country, to provide situational awareness about earthquake occurrences and effects, and help communities in earthquake-prone areas develop safer building protocols. The USGS, with additional support from the states of California, Oregon and Washington, is expanding and upgrading the system on the West Coast. 

The ShakeAlert System is expanding and upgrading the infrastructure of regional seismic networks that are part of the ANSS, including the Pacific Northwest Seismic Network and the California Integrated Seismic Network.  

This enables the USGS, ANSS, and Cal OES to leverage their substantial investment in sensor networks, data telemetry systems, data processing centers, and software for earthquake monitoring activities residing in these network centers. 

The State of California has provided significant funding for the ShakeAlert System and has supported earthquake monitoring since 2001. The State of Oregon appropriated funds to purchase seismic stations to enhance and contribute to ShakeAlert. The State of Washington is strongly supportive of the ShakeAlert System. It provides some base funding of the PNSN and houses the operation at the University of Washington. 

ShakeAlert is a People-Focused earthquake early warning system. An extensive team oversees communication, education, outreach, and technical engagement. To ensure that the ShakeAlert System keeps people as safe as possible, the team recruits new Technical Partners, improves how people use ShakeAlert System through social science studies, and creates educational materials that can be used in schools, museums, and in many other settings. More information on each group follows: 

Technical Engagement

  • Recruits and maintains ShakeAlert Technical Partners and partnerships to develop products and services that contribute to the successful private/public implementation of the ShakeAlert System. 

Social Science  

  • Provides research to help decision makers and administrators of the program to more effectively communicate with, and educate about, the ShakeAlert System and how to optimize human safety. 

Educational Resources   

  • Develops educational resources to increase awareness of the ShakeAlert System, shares resources with communities through a collaborative approach, and assesses the effectiveness of the resources through educational research best practices. 

To learn how to become powered by ShakeAlert, visit 

Keep up with ShakeAlert System Updates and News on Twitter: @USGS_ShakeAlert 

*The date and time are fictional and solely used to demonstrate how an alert works. 



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