宁夏地区近震震级短周期量规函数的研究与修正

选取宁夏"十五"宽频带数字地震台网2009年1月—2016年12月的1 782个地震事件、7 345条地震记录资料,通过震级残差统计和多元回归分析计算各台站单台震级与台网平均震级的偏差、平均偏差和标准偏差,分析震级偏差的频次分布,修正M_L量规函数,得到宁夏地区的地方性均匀震级量规函数和台基改正量。且采用多元回归分析方法,得到最大地动位移的衰减关系及与之对应的量规函数。结果表明,修正后的震级均方差由原来的0.237 0降低为0.228 9,震级修正最大值为0.51。

Research and Modification of Short Period Calibration Function ofLocal Earthquake Magnitude (ML) in Ningxia Area

To calculate the deviation, average deviation, and standard deviation between single-station and average magnitudes in the Ningxia area, we performed a residual and multiple regression analysis of the magnitude, and selected 7 345 items of data from 1 782 seismic events recorded by the Ningxia broadband digital seismic network from January 2009 to December 2016. We analyzed the frequency distribution of the magnitude deviations and modified the calibration function of the local earthquake magnitude (M_L) to obtain the calibration function of the local uniform magnitude system for the Ningxia region. We obtained the attenuation characteristics of the maximum ground displacement and corresponding calibration function by multiple regression analysis. Our results show that the modified mean square variance of the magnitude reduces from 0.2370 to 0.2289, and the maximum modified magnitude value is 0.51.