A New Multi-Sensor Network Developed for the China Earthquake Early Warning System (EEWs)

Date: 4/25/2019

Time: 06:00 PM

Room: Grand Ballroom

The speed and accuracy of an Earthquake Early Warning System (EEWs) is improved by increasing network station density. Recently, a new 3-in-1 network consisting of: (1) Micro-Electro Mechanical Systems (MEMS) sensors, (2) traditional seismometers and (3) accelerometers, was installed by the China Earthquake Administration (CEA) in some regions of China for EEWs. The JJJ region in eastern China, comprising Beijing, Tianjin and Hebei is one such regions. Here the CEA has deployed 370 low-cost MEMS sensors with average spacing of 8-10 km and 220 traditional instruments (seismometers and accelerometers) in this 3-in-1 network. The EEWs in the JJJ region includes the central data processing center and 3 alert centers in Beijing, Tianjin and Shijiazhuang, respectively. The system uses a point-source algorithm (Zhang H. et al., 2016) for event detection, location and magnitude determination. During online testing carried out from 2015 to 2018, the JJJ EEWs network successfully provided alerts for several earthquakes near the Beijing Capital Area. Examples include the 2015 M4.2 Changli, Hebei, earthquake for which the JJJ EEWs issued the first alert 5.4 seconds after the origin time with magnitude error of -0.1 and epicenter location error of 2 km compared to China Earthquake Networks Center catalog. The 2018 M4.3 Yongqing, Hebei, earthquake, occurred on the edge of the high density MEMS network. The first station triggered 5.7 seconds and an alert was issued 9.7 seconds after the earthquake origin time. The EEWs kept updating the analysis, with the most reliable alert just 11.8 seconds after the origin time. The alert messages, including point-source information and the intensity map, were rapidly sent to the pilot-users through three alert centers. The EEWs demonstration project in the JJJ region has successfully completed a series of evaluation and reliability tests, including data collection, transmission, processing, and alert release. The demonstration project provides a solid foundation for the implementation of the China National EEWs.

Presenting Author: Walter D. Mooney

Authors