Employee Wellness

Earthquake Early Warning System at your fingertips

Earthquake warning for california logo.

Warning app warns residents when earthquakes happen

Earthquake Warning California is the country’s first publicly available, statewide warning system that could give California residents crucial seconds to take cover before you feel shaking. Managed by the Governor’s Office of Emergency Services (Cal OES), Earthquake Warning California uses ground motion sensors from across the state to detect earthquakes before humans can feel them and can notify Californians to “Drop, Cover and Hold On” in advance of an earthquake. 

To receive earthquake warnings, individuals and family members can download the MyShake App and ensure phone settings are adjusted to receive emergency alerts, including:

  • MyShake App: Free smartphone app that provides iPhone and Android users with audio and visual warnings [magnitude 4.5 or higher and Modified Mercalli Intensity III (weak) shaking]. Available in the Apple App and Google Play stores;
  • Android Earthquake Alerts: Android phones with updated operating systems are automatically subscribed to Android Earthquake Alerts, which uses the same technology as the MyShake App; and
  • Wireless Emergency Alerts (WEAs): No-cost text messages for emergency situations [magnitude 5.0 or higher and Modified Mercalli Intensity IV (light) shaking].

If you live in or travel to areas that could be impacted by an earthquake, preparation is vital, as these events can strike suddenly, at any time, with little warning. Visit My Hazards to see if you live or work in an area prone to earthquakes.

The California Earthquake Early Warning System uses science, state-of-the-art monitoring technology, and innovative delivery methods to alert people that an earthquake is happening before the anticipated strongest shaking arrives in affected regions.

(Learn more about the warning system app.)

The basics of the earthquake warning app

Having seconds of advanced warning can provide people the opportunity to take lifesaving actions like drop, cover, and hold on, and to put important devices into safe mode.

The alerts that individuals or businesses receive on their devices will vary depending on their distance from the epicenter of the earthquake, with shorter alert times for those closest to the epicenter, and longer ones for those farthest away.

  1. In an earthquake, a rupturing fault sends out three different types of waves. The fast-moving P-wave is first to arrive, but the damage is caused by the slower S-waves and surface waves.
  2. Sensors detect the P-wave and immediately transmit data to an earthquake alert center where the location and size of the quake are determined and updated as more data becomes available.
  3. A message from the alert center is immediately transmitted to users.

Who Benefits from Earthquake Early Warnings?

The Public – individuals can take protective actions such as drop, cover, and hold on

First Responders – teams can begin to mobilize, opening fire station doors for rapid deployment of emergency response equipment and personnel

Health Care Workers – medical providers can stabilize and/or stop delicate procedures and maintain critical medical facility operations

Utility Companies – workers can safeguard the energy sector grid and other utilities infrastructure with warning alarms and automatic controls to prevent combustions, flooding, and loss of water distribution systems

Mass Transit Systems – operators can prevent fatal collisions or derailments by automatically slowing and/or stopping trains, clearing bridges, and diverting inbound airport traffic

Workplaces – employees can take protective actions, initiate elevator ground-floor recall procedures, place sensitive equipment in safe mode, secure hazardous materials, and halt production lines to reduce damage

Learn more at the website.


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