The Great California ShakeOut: Practicing for the Big One

Every October, something strange and coordinated happens across California and dozens of other states and countries. At a designated moment, often marked by the exact minute of the date itself, millions of people simultaneously drop to the ground, take cover under a sturdy piece of furniture, and hold on as if an earthquake had just struck. This is the Great ShakeOut, now the largest earthquake preparedness drill in the world, and its origin story is rooted in one of the most detailed scientific disaster scenarios ever produced.

A Scenario Built by Hundreds of Scientists

The Great California ShakeOut did not begin with a marketing campaign or a government mandate. It began with a scientific research project called the ShakeOut Scenario, completed in 2008 under the leadership of the United States Geological Survey in partnership with the California Geological Survey, the Southern California Earthquake Center, and dozens of other organizations. More than 300 experts contributed to the project, which modeled in extraordinary detail exactly what would happen if a magnitude 7.8 earthquake struck the southern portion of the San Andreas Fault.

The resulting scenario was not a dry technical report tucked away in a scientific journal. It was written as a gripping, moment-by-moment narrative describing the unfolding disaster as if it were actually happening on a Thursday morning, complete with descriptions of collapsing buildings, disrupted water and power systems, and the enormous logistical challenge facing emergency responders across the region. The purpose of building such a vivid scenario was to translate complex seismic science into something concrete enough that ordinary people, city planners, and emergency management agencies could genuinely grasp the scale of the danger and begin preparing for it.

The First Drill Takes Southern California by Storm

The scientific scenario alone was powerful, but researchers involved in the project wanted the public to actually experience preparedness in action rather than simply read about a hypothetical disaster. That idea led to the creation of a live, large-scale earthquake drill, organized through a collaboration led by the Earthquake Country Alliance. On November 13, 2008, the plan came to life as the Great Southern California ShakeOut, based directly on the same magnitude 7.8 scenario the scientists had modeled.

The results exceeded almost every expectation organizers had going in. Over 5.3 million people across eight Southern California counties participated, making it the largest earthquake drill in United States history at the time. The organizers behind the event had set three specific goals when planning began earlier that spring: registering 5 million participants, shifting the broader culture around earthquake preparedness in Southern California, and ultimately reducing the losses a real earthquake might cause. According to a survey conducted the following year, more than 90 percent of registered organizations reported a genuine improvement in earthquake preparedness as a direct result of taking part in the drill.

From a Regional Event to a Statewide Tradition

The success of that first Southern California drill quickly attracted attention well beyond the region where it began. The following year, in 2009, the event expanded to become the Great California ShakeOut, opening participation to the entire state rather than just its southern counties, and attracted 6.9 million participants. Momentum continued building rapidly after that.

The 2010 drill, held on October 21, drew 7.8 million participants, and by 2012, the event had grown to include 9.4 million people statewide, along with the region's rail system participating in drill activities for the first time. By 2017, more than 10 million people were taking part in the California drill alone.

That same year, the first drill was held in California, and something remarkable also happened internationally: in 2009, New Zealand held its own Great West Coast ShakeOut, becoming the first ShakeOut drill to take place outside of California. Given New Zealand's own long history with damaging earthquakes, including the devastating Christchurch earthquake that would strike the following decade, the connection made a great deal of sense, and it marked the beginning of the ShakeOut concept spreading well beyond its California origins.

Growing Into a Global Movement

What started as a single regional drill eventually evolved into an internationally coordinated event supported by the Federal Emergency Management Agency alongside numerous other organizations. Today, Great ShakeOut Earthquake Drills are held across more than 20 official ShakeOut regions, spanning most U.S. states along with countries and territories including Canada, New Zealand, Japan, Puerto Rico, and Guam. Anyone located outside of an official region can still register their own drill and be counted toward the worldwide total, and new regions continue to be added most years.

The event's scale today reflects just how far the original 2008 drill has traveled. More than 30 million people worldwide participated in 2022, and recent California drills alone have drawn more than 10 million registered participants in a single state, including more than 5 million K-12 students and staff members. The drill has become such an established part of the academic calendar in California that participating in it now helps schools and districts satisfy state earthquake drill requirements each year.

Why the Drill Is Timed So Precisely

One of the more memorable features of the Great ShakeOut is its habit of scheduling the drill at a time that mirrors its own date, such as beginning at 10:19am on the 19th of the month, or 10:16am on the 16th. This precise timing is intentional, designed to make the moment easy to remember and to help create a shared, synchronized experience across every participating time zone, even though individual organizations are always free to register and practice their drill on a different day or time if that works better for their schedule.

The drill itself centers on a simple three-step action known as "Drop, Cover, and Hold On." Participants drop to the ground wherever they are, take cover under a sturdy piece of furniture, like a desk or table, and hold on to that object while protecting their head and neck until the shaking stops. Research examining earthquake injuries has repeatedly supported this technique as one of the most effective ways to reduce harm during a real earthquake, and the ShakeOut has also worked to expand its safety guidance to address situations the technique does not automatically cover, such as what to do if an earthquake strikes while someone is outdoors, driving a car, or unable to physically drop to the ground due to a disability.

A Blueprint for Preparedness Elsewhere

The influence of the Great ShakeOut has extended well beyond earthquake safety alone. The basic model it pioneered, translating rigorous scientific hazard research into a single, memorable, large-scale public participation event, has since inspired preparedness campaigns addressing other natural hazards in different parts of the country, adapting the same core idea of coordinated practice and public education to entirely different types of disasters.

Within the world of seismology specifically, the ShakeOut also helped popularize the value of a detailed, narrative-driven disaster scenario as a public communication tool, rather than relying solely on technical statistics and probability estimates that can be difficult for non-scientists to fully internalize. The success of that approach continues to shape how emergency management agencies and research institutions communicate risk to the public today.

The Bottom Line

The Great California ShakeOut began as a rigorous scientific exercise involving hundreds of researchers and grew, almost unexpectedly, into the largest earthquake preparedness drill the world has ever seen. Its evolution from a single regional event in 2008 into an international movement spanning dozens of regions and tens of millions of annual participants reflects something important about disaster preparedness more broadly: that turning complex science into a shared, memorable, and repeatable public action can genuinely change how communities respond when disaster eventually strikes.

Sources

1. United States Geological Survey. "The 2019 Great ShakeOut." USGS News, 2019.

2. Jones, L. M., and Benthien, M. "Preparing for a 'Big One': The Great Southern California ShakeOut." Earthquake Spectra, 2011.

3. Jones, L. M., and The ShakeOut Team. "Preparing a Population for an Earthquake Like Chi-Chi: The Great Southern California ShakeOut." U.S.-Iran Seismic Workshop Proceedings, 2009.

4. Wikipedia. "Great Southern California ShakeOut." Reference entry, 2026.

5. Colorado Geological Survey. "The Great ShakeOut." 2024.

6. CRMP. "The Great California ShakeOut Drill." 2025.

7. CBS News. "California's Annual Statewide Earthquake Drill Is Today. Here's What to Know About the Great ShakeOut." 2023.

8. City of Long Beach. "Great ShakeOut 2024: Join in the World's Largest Earthquake Drill." 2024.

9. ShakeOut.org. "The Great California ShakeOut 2025" and 2025 statewide and worldwide participation totals, Statewide California Earthquake Center, University of Southern California.

10. California Department of Education. "The 2025 Great California ShakeOut." Official memo to county and district superintendents, 2025.