陕西数字地震台网子台测定近震震级的偏差

使用陕西数字地震台网数字地震记录资料，以台网平均震级为标准震级，分析各子台的震级偏差。结果表明，在150km震中距范围，子台测定震级偏差随震中距增大而减小，大于150km，震级偏差不明显。合阳、蒲城、华阴子台台基影响为正值，安康、汉中、彬县子台台基影响为负值，其他子台影响较小。震级偏差随方位角变化是明显的，且具有区域性相似特征。子台方位的震级偏差校正，台网震级标准误差显著改善样本数占81．7％，平均标准误差由0．243下降到0．168。

Deviations in determination of local earthquake magnitude for substations of Shanxi Digital Seismograph network

Using the digital data recordings by Shanxi Digital Seismic network and adopting network average magnitude as standard magnitude,we had analyzed deviation of determination of local earthquake magnitude.The results indicate that magnitude deviations are related to epicentral distance within the 150 km,and not obvious when over the 150 km.The station deviation is positive value for Heyang,Pucheng and Huayin substations,is negative value for Ankang,Hanzhong and Binxian,is not obvious for others.The deviations is significant with seismic azimuth,and there are similar characteristics of region. Correction of magnitude deviation of azimuth which are 81.7% of total stations,had improved the network magnitude standard deviation remarkably,the average standard deviation had decreased from 0.243 to 0.168.