Earthquakes produce multiple types of waves – P waves, and S Waves – which travel at different speeds. P waves (Primary waves/Pressure Waves) rarely cause damage, and travel about 2x as quickly as S Waves (Secondary waves, or Shear Waves – which usually cause more damage than P-Waves). A dense network of seismometers along the U.S. West Coast can detect the P waves, calculate the magnitude and estimated shaking intensities from the earthquake, and send out an alert to the areas most likely to experience shaking.  A “ShakeAlert” is received by a variety of systems, such as phone applications, messaging systems, other computers systems, which automatically take action upon receiving the alert.

Earthquake Early Warnings (EEW) are issued by the United States Geological Survey (USGS). The USGS has the Federal responsibility to issue alerts for earthquakes, to enhance public safety, and to reduce losses through effective forecasts and warnings.  While the alert originates from USGS, you will likely receive the alert through another medium, such as a phone application, or over a PA system.

Every available technology will be used to ensure that ShakeAlerts reach as many people as possible as quickly as possible.  Most currently available mass messaging technologies are too slow for timely ShakeAlert deliveries. However, many promising technologies are becoming available like broadcast text messaging, smartphone apps and recent upgrades to the national Integrated Public Alert and Warning System (IPAWS). ShakeAlert applications will open the door to many public/private partnerships as private companies develop innovative products and services to use and distribute ShakeAlerts.

Users must know how to respond to ShakeAlerts for them to be effective. The USGS and its West Coast partners manage a communication, education, outreach program to make people aware of the ShakeAlert System, its limitations, and how to respond including using the recommended protective actions to ShakeAlerts. Responses are most effective when automated and pre-established so the recipients know what action to take when they get a ShakeAlert.

No. Earthquakes cannot currently be predicted.  This is an alert message that an earthquake has already occurred in your area, and as a result, you may be affected by shaking.  It’s similar to receiving a severe thunderstorm warning, indicating that there is already a hazard in the area, and you should take action to protect yourself.  The main difference here is that you have seconds to take action, as opposed to minutes or more.

Seconds to tens of seconds.  Earthquakes farther away from your current location (remember farther away could also mean deeper beneath your feet) will provide more time between the earthquake warning and the actual shaking from the earthquake.  However, it is important to note that some locations very close to a fault will not be able to be alerted. In these cases, an alert may arrive several seconds after shaking.

Take protective action, such as “Drop, Cover, and Hold on.” The warning will not tell you how much time you’ll have before the shaking arrives; an alert could mean seconds, or tens of seconds – you won’t know. Quickly look around, find the most appropriate way to protect yourself, and prepare for shaking.  For information on what to do during shaking in different locations and situations you may find yourself, visit

If you are near the shore or coastline, strong earthquake shaking may be your only warning of an approaching tsunami.  Take the recommended protective actions, such as Drop, Cover and Hold on, then once the shaking stops, move quickly get to high ground.

Some applications may have follow-up messaging after an earthquake.  There will be follow-up messaging from USGS following a false alert, and in the unusual case a message wasn’t sent before earthquake shaking.

The ShakeAlert Early Earthquake Warning System is operational today.

The system currently has Pilot Users – technical users such as schools, businesses, industrial sites and response agencies – already performing automatic actions when they receive a ShakeAlert from USGS’s system, such as public address (PA) announcements, slowing trains, or closing water and natural gas valves. 

At this time, the system cannot send alert messages to personal cell phones in Washington State.  A public alerting system in the Pacific Northwest will likely be available within the next two years (as of July 2019)

Becoming a pilot user or getting access to the system from USGS does not cost anything.  The actual costs will be for computer systems capable of taking the ShakeAlert and programming an automatic response. There are some simple, inexpensive computers (e.g., Rasberry Pi) that are effective, but it may This cost can also vary greatly depending on how many systems will be connected to ShakeAlert, the age, and interconnectivity of the equipment, and other factors.  As more Pilot users emerge, there will be more details available about costs.

Potential Pilot Projects have expressed some of the challenges they see with setting up a system.  Some of the key issues presented are individual project costs, gaining support, and prioritizing this system.  For more information on responses from different sectors, visit (link to section on sector symposiums)

State and Federal partners are here to connect potential system users with information they need to make the system successful, including education, training, and outreach. State Coordinators will be your support network to help connect you with others who are doing similar projects on the west coast. Federal partners will help you with system updates, and with making sure the technology works properly for what you are trying to do.

Yes!  Several examples include the system in Japan, which is very similar to USGS’s ShakeAlert, and early warning system in Mexico City, which alerts using sirens, and other outlets such as radio and television.  Other countries with that currently have or are currently developing include Taiwan, India, China, Turkey, Israel, Italy, and Romania.

While developing and implementing ShakeAlert, USGS worked to learn best practices from these other systems.

ShakeAlert Earthquake Early Warning has held several Sector Symposiums, focusing on how Earthquake Early Warning could be used in various scenarios, and asking the representatives from those sectors about their needs to create a successful system. Please visit our sector symposiums page to learn more about the results of these events.

Unfortunately, no – there are a couple of reasons for this.

1) there are many earthquakes every day, though most are too small to feel. Earthquake Early Warning systems set thresholds, or limits to both the magnitude and intensity of earthquakes which they would like to be alerted about.  In many cases, you will be alerted to an earthquake that you feel, but some users may wish to set their threshold higher, to only be alerted about earthquakes where the shaking they experience will be strong enough to cause damage.

2) Some earthquakes occur too close to the user for an alert to be sent, for example if the fault generating the earthquake is only several miles away, or directly underneath the user.  Alerts will still be sent, but they may arrive after the shaking begins. These alerts will still reach users further from the earthquake source.

A ShakeAlert can provide time for you to take specific protective actions, such as Drop, Cover, and Hold on. These actions have been proven to reduce injury in an earthquake.

An earthquake early warning linked to technical users can also reduce chances of injury in some cases, such as the Project being implemented by the Bay Area Rapid Transit (BART) trains in San Francisco – when the system receives a ShakeAlert, the trains slow and stop.  This helps minimize derailments, and high speed crashes, protecting both the passengers, and the transit system infrastructure, minimizing both repair costs, and the time it might be out of service due to damage from the earthquake

In Japan jobs have been created in the private sector.  Several advanced technology companies evaluate the needs of each ShakeAlert user and provide value-added application technology to the EEW signals from the Japanese Meteorological Agency (JMA).  Such private-sector products also tailor the EEW signal for use in specific applications such as for equipment protection and safety in semi-conductor factories.

We anticipate that private companies in the US will develop smart ShakeAlert-user technology to take automated actions based on ShakeAlerts generated by the USGS. Such technology may safeguard the energy grid, water systems, rail transportation, open firehouse garage doors, move elevators to the nearest floor, warn doctors treating patients, sound alarms via public address systems in schools, as well as have numerous smart industrial applications. Possible damage to pumping stations in the water system could be mitigated with ShakeAlerts.  Also, people working in hazardous environments can be warned to enable them to move to safety before shaking arrives. There will be may applications for ShakeAlert that will make us all safer and speed recovery after damaging quakes.

If you are on the coast or near the shore and you receive a ShakeAlert, use the recommended protective actions, such as Drop, Cover, and Hold On, or protect yourself appropriately for the situation first.  When the shaking subsides, move quickly to high ground. An Earthquake may be the only warning you receive before a tsunami arrives. It should be noted, during strong shaking, many people have been injured while trying to walk or run while the ground is moving. Protect yourself during the shaking, then evacuate.

Close Menu