Progress of the earthquake early warning system in Fujian, China

In this article, we systematically introduce the latest progress of the earthquake early warning (EEW) system in Fujian, China. We focus on the following key technologies and methods: continuous earthquake location and its error evaluation; magnitude estimation; reliability judgment of EEW system information; use of double-parameter principle in EEW system information release threshold; real-time estimation of seismic intensity and available time for target areas; seismic-monitoring network and data sharing platform; EEW system information release and receiving platform; software test platform; and test results statistical analysis. Based on strong ground motion data received in the mainshock of the Wenchuan earthquake, the EEW system developed by the above algorithm is simulated online, and the results show that the system can reduce earthquake hazards effectively. In addition, we analyzed four earthquake cases with magnitude greater than 5.5 processed by our EEW system since the online-testing that was started one year ago, and results indicate that our system can effectively reduce earthquake hazards and have high practical significance.