新震级国家标准在四川台网的应用——宽频带面波震级

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

利用四川区域地震台网记录到的国内2009—2016年间的217次地震事件,重新测定宽频带面波震级M_(S(BB))、面波震级M_S和部分矩震级M_W,并进行对比分析,结果显示:(1)M_S与M_(S(BB))差值分布为-0.1~0.6,其中97%的地震M_S较M_(S(BB))偏大,通过正交回归分析,M_(S(BB))较M_S系统偏小0.27左右;(2)M_W与M_S差值为-0.8~0.35,其中M_W与M_S差值在±0.3以内的地震数约为74%,由正交回归分析4.0≤M≤8.0时M_S整体偏大,且偏差值随着震级的增加呈上升趋势,偏大范围为0.1~0.4之间;(3)M_W与M_(S(BB))差值分布为-0.5~0.55,差值在±0.3以内地震占87%,正交回归分析出4.0≤M≤5.0时M_W较M_(S(BB))偏大,偏大范围为0~0.13,而5.0≤M≤8.0时M_W较M_(S(BB))偏小,偏差值均在0.23以内。总体来说,相较于M_S,M_(S(BB))与M_W的偏差更小,M_(S(BB))更接近地震矩震级M_W,更能准确评估地震震级。

We calculated the broadband surface wave magnitude MS（BB）, surface wave magnitude MS and partial moment magnitude MW 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 MS（BB） and MS is -0.1～0.6, for 97% earthquakes, MS is greater than MS（BB）. The orthogonal regression analysis result shows, MS（BB） is about 0.27 less than MS. The difference between MW and MS is -0.8～0 35, for 74% earthquakes, the difference between MW and MS is within ±0.3. Through orthogonal regression analysis, for 4.0≤M≤8.0 earthquakes MS is greater than MW, the deviation range from 0.1～0 4 and increase with magnitude increasing. The difference between MW and MS（BB） is -0.55～0.5, for 74% earthquakes, the difference between MW and MS is within ±0.3. By orthogonal regression analysis, for 4 0≤M≤5.0 earthquakes MW is greater than MS（BB）, the deviation range from 0.1～0.13, for 5.0≤M≤8 0 earthquakes MW is less than MS（BB）, the deviation within 0.23. On the whole,the difference between MW and MS（BB） is less than MW and MS. That is, because of closer to MW, broadband surface wave magnitude MS（BB） can more accurately evaluate the magnitude of earthquake.