山西地震带b值空间分布与构造应力场的关系研究

Study of Relationship between the Spatial Distribution of B Value and the Tectonic Stress Field in Shanxi Seismic Zone

利用山西地震带1970年以来的中小地震目录,计算了该地震带的b值空间分布。在回顾性总结山西地震带构造应力场特征的基础上,分析了其与b值空间分布的关系,并探讨了b值空间分布所反映的构造应力场特征。研究结果显示,山西地震带上震源机制解中T轴方位近似垂直于b值等值线的切线,P轴近似平行于b值等值线的切线,暗示断陷盆地内的低b值状态与断裂的构造特征和活动方式有关。

Using the earthquake catalog in Shanxi seismic zone since 1970,the spatial distribution of b value is calculated.Based on a summary of the tectonic stress field in Shanxi seismic zone,the relationship between the tectonic stress field and the spatial distribution of b value is studied,and the characteristic of tectonic stress field indicated by the spatial distribution of b value is also discussed.The result shows that the T axes in focal mechanism solutions of Shanxi seismic zone are approximately perpendicular to the tangent of the b value contours as well as the P axes are approximately parallel to the tangent of the b value contours,and implies that the lower b values in the graben basin are related to structure characteristics and faulting patterns of fault.