【摘要】 2013年4月20日龙门山断裂带南段发生Ms7.0级芦山地震,通过计算多个地震活动参数,定量分析芦山地震发生的背景地震活动性及与汶川地震的关联性.结果表明:1)历史记载龙门山断裂南段仅有3次6.0级以上强震,存在地震空区的历史地震背景;2)通过a值分析可知,芦山地震发生前30年背景地震活动性较高;3)分析汶川地震前后b值的空间分布差异,发现龙门山断裂南段在汶川地震后仅部分区域b值下降,应力增强,芦山地震发生在b值明显下降区.更多还原

【Abstract】 The Ms7. 0 Lushan earthquake occurred in the southern part of Longmenshan fault on 20 April 2013. We calculate several kinds of seismic activity parameters to analyze the background activity of Lushan earthquake and relate them with Wenchuan earthquake. The results show that 1)there were only three great earthquakes above M6. 0 occurring in the southern part of Longmenshan fault,which indicates existence of earthquake gap in historic earthquake background; 2) based on the values of a,the background earthquake activity was high during the 30 years before Lushan earthquake; and 3) the spatial difference in b-value before and after Wenchuan earthquake shows decrease of b-value and increase of stress only in part of southern Longmenshan fault zone while Lushan earthquake occurred in the region where b-value decreased apparently.更多还原