Magnitude measurement and explosive yield estimate using the data of Hailar seismic array

There were three explosions occurred in northest Asia on January 6, 2016, September 9, 2016, and September 3, 2017. Using the data of Hailar seismic array, the amplitudes of P-phase and Lg-phase of the three explosions were picked up, the amplitude spectrum were calculated, the magnitude were measured, and the yield were estimated. The results of amplitude picking and amplitude spectrum calculation show that the low-frequency component of Lg-phase for the 2017 event is more developed than those of the previous two, and the amplitude is relatively larger, which is inferred to be related to the explosion damage mechanism or explosion technical process. The short-period body wave magnitude m_b（P） calculated by using the national standard for the three explosions are 5.3±0.1, 5.6±0.1 and 6.1±0.1, respectively. The short-period body wave magnitude m_b（Lg） calculated by using the third peak method of Lg-phase for the three explosions are 4.33±0.05, 4.56±0.4和5.60±0.03, respectively. The average yield results obtained by m_b（P） and m_b（Lg） through the magnitude-yield empirical formula were taken as the yield results of the three events, which were （14.4±4.3）, （34±11.6） and （190.4±45.4） kt, respectively. The energy of the explosion event in 2017 was 5.6 times as much as that of the event in September 2016 and 13.2 times that of the event in January 2016.