ANALYSIS OF CURRENT ACTIVITY AND STRONG SEISMIC RISK ON THE NORTHERN PART OF TANCHENG-LUJIANG FAULT ZONE

According to the latest seismic datum over past 38 years, using b-value spatial distribution combines several other seismic activity parameters, we analyse the activity on each segment of the Tancheng-Lujiang fault zone, and find out the strong and medium strong earthquake potential segments.The result indicates that there are 4 sub-segments of different activity in the northern segment of Tancheng-Lujiang fault zone, in which, middle south Bohai sea segment is in a locking position under middling stress background with the main characteristic of small earthquake sliding, belonging to a strong earthquake potential segment with certain strain accumulation;Shengyan-Tuchang segment is in a locking position under higher stress background with the main characteristic of fewer small earthquake sliding, belonging to a strong earthquake potential segment with long-term strain accumulation;Yingko-Haicheng segment is active after the 1975 Ms 7.3 earthquake, so this segment is in a stage of post-earthquake hypocenter stress adjustment with low b-value and high stress state, the main characteristic of this segment is frequent medium and small earthquake sliding with lower earthquake risk in near future.Liaodong Bay segment is under a low stress background with the main characteristic of fewer small earthquake sliding, and then, in a lower probability of medium and strong earthquake risk.Under low stress background with small earthquake sliding, the Liaodong Bay segment is in low strong earthquake potential.