CISN ShakeAlert: An Earthquake Early Warning Demonstration System for California

To demonstrate the feasibility of earthquake early warning (EEW) in California, we have developed and implemented the CISN ShakeAlert demonstration system. A Decision Module combines estimates and uncertainties determined by three algorithms implemented in parallel, \(\tau _\mathrm{{c}}-\mathrm{{P}}_\mathrm{{d}}\) Onsite, Virtual Seismologist, and ElarmS, to calculate and report at a given time the most probable earthquake magnitude and location, as well as the likelihood of correct alarm. A User Display receives the alert messages in real-time, calculates the expected local shaking intensity, and displays the information on a map. Currently, CISN ShakeAlert is being tested by \(\sim \)70 individuals and test users from industries and emergency response organizations in California. During the next 3 years we plan to expand this demonstration warning system to the entire US West Coast.