本文以b值作为研究对象，在b值由应力状态和介质性质共同决定的理论框架下，开展了河套地震带的b值时空变化特征分析。选取1970年发生在河套地震带的M_L ≥ 1.5地震作为考察对象，运用EMR方法定量检测了最小完整性震级M_c的时序非均匀变化，并根据研究区地震活动实况，确定b值的起算震级为M_L2.0。运用最小二乘法进行了b值时间扫描计算，结果显示，b值时序变化较好地对应了研究时段内的中强地震活动、台网分布和余震剔除等变化因素。运用极大似然法进行了b值空间扫描计算，结果显示，河套地震带的b值空间差异可能由地壳介质体性质和应力环境共同引起，相对来讲，b值的构造相依特征更为明显。此外，满足各震级档有足够多的地震样本依然是提高b值计算精度的关键环节。

This paper targets at b-value which had been researched quite a lot at home and abroad. b-value is determined by stress state and dielectric properties in the theoretical framework. We analyze the variation characteristics of the b-value in the Hetao seismic belt. We select the earthquakes with M_L≥1.5 which occurred in the Hetao seismic belt since 1970,conduct the quantitative detection of the non-uniform temporal change of M_C by using EMR method,and based on the actual situation of seismic activity,set the lower limit magnitude as M_L2.0 to calculate b-value. We calculate and scan the temporal variation of the b-value by using least square method. The results show that there is a good corresponding relationship between the temporal variation of b-value,strong earthquake activity,network distribution and aftershock deletion. We also calculate and scan the spatial variation of b-value by using maximum likelihood. The results show that the spatial difference is possible caused by stress state and dielectric properties.,b-value relies more relatively on the tectonic property. In addition,the sufficient earthquakes samples in each magnitude interval are still a key step to improve the calculation accuracy of b-value.

内蒙古自治区科技重大专项“重点地区地震预测预警技术研究开发与推广示范”项目、中国地震局监测预报司震情跟踪面上项目（2017020102）”共同资助