Development of an integrated onsite earthquake early warning system and test deployment in Zhaotong, China

Earthquake Early Warning System (EEWS) is one of the effective ways to mitigate earthquake damage and can provide few seconds to tens of seconds of advanced warning time of impending ground motions, allowing for mitigation measures to be taken in the short term. In the present paper, we develop an integrated onsite EEWS called EDAS-MAS, which is based on the physical characteristics of the P-wave velocity greater than S-wave velocity. The instrument is a single device which includes a 3-channel MEMS accelerometer, a data acquisition unit, seismological processing, and three types of alarms. Two types of magnitudes are computed by using τc-Pd values and the estimated hypocentral distance. It can directly raise the warning to the public when the magnitudes exceed the predefined thresholds, providing longer effective warning time and reducing the “blind zone” range. Although a majority of the reported events were small earthquakes and a relative high false alarms rate existed in the test, the results have shown the capabilities of the prototype EDAS-MAS for EEWS and are of practical importance for the design and optimization of the system.