Status of Earthquake Early Warning in California
The California Governor’s Office of Emergency Services (Cal OES) is working diligently with the U.S.Geological Survey (USGS) and other governmental and nongovernmental organizations to bring earthquake early warning to California. Major milestones are the creation of the California Earthquake Early Warning Program (CEEWP) and the California Earthquake Early Warning Advisory Board by Senate Bill 438 (Hill and Hertzberg).
Cal OES received $10 million in General Funds from the State of California in 2016 and another $15.75 million 2018. The funding is being used to install or upgrade a total of 463 seismic sensors which complete the seismic network. The funding is also used for the research and development of new technologies; provide communication, education, training, and outreach; and support the Earthquake Early Warning Advisory Board.
Cal OES is working closely with public, private, and non-profit partners to develop new pathways to get ShakeAlerts to people within the next year. One method is to use datacasting, excess transmission with digital television signals to provide information to specialized receivers sparking auditory and automated actions. The distribution technology is being tested.
For more information about the current status of the multi-state USGS ShakeAlert system, click here.
Earthquake Early Warning (EEW) systems use science, state-of-the-art monitoring technology, and innovative delivery methods to alert people via devices before the anticipated strongest shaking arrives in affected regions. Seconds to tens of seconds of alert can provide opportunity to take life-saving actions such as Drop, Cover, and Hold On.When an earthquake occurs, two main forms of seismic waves are produced. The faster and usually less damaging primary (P) waves precede the much slower damaging secondary (S) waves. Technology now exists that can quickly detect the energy from P-waves once they reach the surface to estimate the location and the magnitude of earthquakes and provide warning before the more destructive S-waves arrive. This makes it possible to detect a large earthquake and broadcast a ShakeAlert to projected areas of impact before the strong shaking arrives at that location.
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.
The earthquake early warning system in California will be able to provide seconds to tens of seconds of alert prior to strong shaking. People may receive a ShakeAlert before, during, or after shaking arrives at their locations. The length of time warning given to any location, before, or after shaking begins depends on a number of factors, including: