[J04-2] Geohazard early warning systems II

[J04-2-01] Magnitude scaling relationships from the first 3s of P-wave arrivals in Mainland of China

^○Jindong Song^{1, 2}, Dongwang Tao^{1, 2}, Shanyou Li^1,2, Qiang Ma^1,2, Haiying Yu^1,2 (1.Institute of Engineering Mechanics, China Earthquake Administration, Harbin, China, 2.Key Laboratory of Earthquake Engineering and Engineering Vibration, Harbin, China)

One of the critical technologies of earthquake early warning is determining the size of an earthquake from the first few seconds after the P-wave arrivals. We derive empirical magnitude scaling relationships for mainland of China using a dataset of 214 past earthquakes and 2511 vertical waveforms recorded in mainland of China by China Strong Motion Networks Center (CSMNC) between 2007 and 2015. The events range in magnitude from 4.0 to 8.0. We use the predominant period (tau-c) and the peak displacement amplitude (Pd) measured from the first 3 seconds of P-wave arrivals to determine period-magnitude and amplitude-magnitude scaling relationships respectively. The average error in magnitude estimates is 0.3 magnitude units for events with magnitudes ranging from 4.0 to 6.5, and 0.5 magnitude units for events with magnitudes greater than 6.5. we observe the saturation effect for magnitudes greater than 6.5, especially in amplitude-magnitude scaling relationships. In cases of the Ms 8.0 Wenchuan earthquake and the Ms 7.0 Lushan earthquake, such warnings would be available within 10s of the origin time of a large earthquake. Our magnitude scaling relationships may be useful for developing an earthquake early warning system in mainland of China.