内蒙古数字地震台网快速测定速报震级结果评估

利用2014—2018年内蒙古及邻省数字地震台网108个宽频带固定地震台站的事件波形数据,分别采用快速测定速报震级方法和常规速报震级测定方法对85例有效速报地震进行分析,测定两种方法的震级偏差,给出震级校正值,并对结果进行对比。结果表明:(1)快速测定法的结果与常规速报震级方法测定结果相比整体偏小,震级差绝对值介于0~0.5之间,平均震级差为0.25,对不同震级差频度分布进行高斯分布函数拟合,震级差分布符合高斯正态分布;(2)分别测算两种方法量取振幅测定震级的时间,快速测定法用时为常规速报震级方法的3/5,平均节约时间90 s左右,减少速报报出时间;(3)对于地震震级偏小并且垂直分量的S波发育不完全的地震事件,不建议采用快速测定速报震级方法测定震级;(4)采用校正后的震级测定结果,精度有所提高,减小了震级偏差对地震速报的影响,因此该方法适用于地震台网速报的处理要求,可以提供较为可靠的参考。

Evaluation of Standard Magnitude by Rapid Determination Method in Inner Mongolia Autonomous Region Digital Seismic Network

Based on waveform data recorded by 108 broadband seismic stations of the Digital Seismic Network in Inner Mongolia Autonomous Region and neighboring provinces during period of 2014—2018,the magnitude of 85 earthquakes were computed by using the rapid determination method and the conventional determination method,at the same time,the magnitude deviation of the two methods were measured and the magnitude correction is given,in the end,the results of the two methods were compared.The results show that:(1)The magnitudes calculated by the rapid determination method is smaller than that calculated by conventional determination method,the absolute magnitude deviation range between 0 and 0.5,the mean value of magnitude deviation is 0.25.Using Gauss curve fitting,it is indicated that the distribution of magnitude deviation is still the Gaussian’s’s.(2)Measuring time of magnitude which is determined by amplitude is given,the time using rapid determination method is 0.6 times that using conventional determination method.On average,It’d probably cut that time by 90 minutes,and it will reduce the time on quick report.(3)The rapid determination method is not recommended for small earthquakes,which of S-wave does not develop well for vertical component.(4)It may diminish the influence of magnitude deviation to the fast determination of earthquake parameters and improve the magnitude determination accuracy in Inner Mongolia Digital Seismic Network.This method may provide a reliable reference basis for rapid determination of standard magnitude.