Application of the New National Magnitude Standards in Sichuan Network-Broadband Surface Wave Magnitude

We calculated the broadband surface wave magnitude M_S(BB), surface wave magnitude M_S and partial moment magnitude M_W of 217 earthquakes in China recorded by Sichuan Seismic Network from 2009 to 2016. The systematic comparison and analysis research of the results shows:the difference between M_S(BB) and M_S is -0.1~0.6, for 97% earthquakes, M_S is greater than M_S(BB). The orthogonal regression analysis result shows, M_S(BB) is about 0.27 less than M_S. The difference between M_W and M_S is -0.8~0.35, for 74% earthquakes, the difference between M_W and M_S is within ±0.3. Through orthogonal regression analysis, for 4.0 ≤ M ≤ 8.0 earthquakes M_S is greater than M_W, the deviation range from 0.1~0.4 and increase with magnitude increasing. The difference between M_W and M_S(BB) is -0.55~0.5, for 74% earthquakes, the difference between M_W and M_S is within ±0.3. By orthogonal regression analysis, for 4.0 ≤ M ≤ 5.0 earthquakes M_W is greater than M_S(BB), the deviation range from 0.1~0.13, for 5.0 ≤ M ≤ 8.0 earthquakes M_W is less than M_S(BB), the deviation within 0.23. On the whole,the difference between M_W and M_S(BB) is less than M_W and M_S. That is, because of closer to M_W, broadband surface wave magnitude M_S(BB) can more accurately evaluate the magnitude of earthquake.