断层活动协调比计算方法的改进及震例分析

Improvement and seismicity analysis of fault motion coordination ration

摘要:

根据断层活动协调比的概念,讨论了起算点对协调比计算结果的影响,提出了移动窗计算断层活动协调比的方法以及离散度评定指标。震例分析结果表明,丽江7.0级地震前丽江场地断层活动协调比数值变化范围较大,分布较离散;震后数值相对稳定,离散度较低。反映了在孕震阶段断层的应变积累以及由其引起的3分量运动相互协调性较差;震后断层处于自由活动状态,积累的应变能得到释放,3分量运动相互协调一致。目前丽江场地断层活动协调比数值离散度处于低值,断层应变积累处于较低水平。

Abstract:

Based on the concept of fault motion coordination ration （FCR）, the paper discussed the effect of the starting point on the result of FCR calculation and proposed a calculation method of FCR using sliding windows and an evaluating index of dispersion. The case study of the Lijiang site indicates that the FCR of Lijiang site distributed more widely and discretely before the MT. 0 Lijiang earthquake than after it, which reflected strain accumulation and caused poor movement coordination during the seismogenic period. After the earthquake the fault is in a free activity state, and the accumulated strain energy is released, and 3-component movements are consistent to each other. At present, FCR dispersion of Lijiang is low and fault strain accumulation is also at a low level.