摘要
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ML≥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Mc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ML2.0。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 ML ≥ 1.5 which occurred in the Hetao seismic belt since 1970, conduct the quantitative detection of the non-uniform temporal change of Mc by using EMR method,and based on the actual situation of seismic activity, set the lower limit magnitude as ML2.0 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.
出处
《中国地震》
北大核心
2016年第3期522-532,共11页
Earthquake Research in China
基金
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
关键词
河套地震带
B值
时空扫描
余震删除
误差分析
Hetao seismic belt
b-value
Spatial and temporal scan
Aftershock deletion
Error analysis
