Effects of Static Stress Triggering of the Major Earthquake Sequence on Xiaojiang-Zemuhe Fault Zone

In this article,we calculate and map the patterns of Coulomb stress changes induced by a major earthquake sequence of 4 events M≥7 on the Xiaojiang-Zemuhe fault zone in 1733 to 1850,and analyze the effects of the static stress triggering induced by the individual preceding events to the following events.The results show that,in the sequence of major earthquakes,every following event occurred in an area where Coulomb stress had been remarkably increased by the preceding event(s).For instance,both the M=73/4 earthquake of 1733 on the northern segment of the Xiaojiang fault zone and the M=8 earthquake of 1833 on the middle segment of the fault zone induced positive increments of Coulomb stress on the Zemuhe fault zone,suggesting that the occurrence of the M=71/2 earthquake of 1850 on Zemuhe fault zone is related to the stress triggering effects caused by the 2 preceding major events.Again,the M=73/4 earthquake of 1733 on the northern segment of the Xiaojiang fault zone and the M=7 earthquake of 1789 on the middle-southern segment of the fault zone produced remarkable Coulomb stress triggering effects on the middle segment of the fault zone,that is related with the occurrence of the M=8 earthquake of 1833 on the middle segment of the fault zone.Therefore,we believe that mechanically significant interactions exist among the different segments of the Xiaojiang fault zone,as well as between the fault zone and the Zemuhe fault zone.