山西地区不同时段地震目录最小完整性震级研究

Minimum Magnitude of Completeness for Earthquake Catalogues of Different Periods in Shanxi Region

对地震目录的最小完整性震级MC的科学评估,是进行地震活动性和地震危险性分析的重要基础,而最小完整性震级MC又是表征台网监测能力的关键参数。本文据山西地震观测台网建设时间的阶段性差异,将其分为4个时段,以1970—2012年山西地区地震目录为基础资料,利用震级-序号法、最大曲率法(MAXC)、90%和95%的拟合度GFT法,研究了不同时段山西地区地震目录最小完整性震级MC的时序变化特征。1970年以来随着山西测震台网的改造,MC逐步降低,尤其是"十五"数字化台网改造后,山西ML≥0.9地震基本完整,表明山西地震监测能力逐步提升。

The minimum magnitude of completeness （Me） in earthquake catalogues, which reflects the network monitoring capability, plays an important role in studying seismicity and assessing seismic hazards. Considering the fact that Shanxi Seismic Network was es- tablished in different periods, the paper divided it into 4 periods. Based on the 1970--2012 earthquake catalogues in Shanxi region, we analyzed temporal variation of the minimum magnitude of completeness for earthquake catalogue by using the magnitude-order num- ber, the maximum curvature （MAXC） and the goodness-of-fit test （GFT） methods. The results showed that the minimum magnitude was gradually lowered with the upgrading of seismic network from 1970, and MC could reach as low as ML0. 9 after the ＂Tenth Five- Year Plan＂, which indicated that the monitoring capability had been significantly im- proved.