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Title:: Characteristics of Coda Wave Attenuation in Yishu Fault and Its Adjacent Area

Author(s):: LI Xia; LIU Xiqiang; LI Xiaohan; ZHAO Jinhua; (Shandong Earthquake Agency,Jinan 250102,Shandong,China)

Keywords:: coda attenuation; method improvement; spatial distribution; Yishu fault

摘要:: 依据沂沭断裂带及其附近地区断裂特征和应力场分布的分段特性将其划分为4个子区域,利用改进后的尾波Q_c值测定方法计算了2010—2017年各子区域内M_L≥2.0地震的尾波Q_c值,并对其空间分布特征进行了研究。结果显示:①沂沭断裂带尾波Q_c值(1 Hz时的Q_c值)整体差异不大,但显示出较好的分段特性,即莱州湾和附近海域平均尾波Q_c值(34.95)明显高于其它区段,潍坊—孟疃段(23.22)、新沂—宿迁段(21.12)平均尾波Q_c值相对偏低; ②尾波Q_c值空间分布与区域介质的地壳构造特点及地质环境关系紧密,揭示了沂沭断裂带作为构造边界带的属性。

Abstract:: According to the characteristics of the tectonic fault and stress field orientation in the Yishu fault zone and its adjacent area,we divided the study area into four sub-areas. Then we calculated the Q_c value of M_L≥2.0 earthquakes in each sub-areas from 2010 to 2017 by the improved Q_c-value measurement method,and studied the temporal and spatial distribution characteristics. The results show that:①The Q_c value of the coda wave(Q_c value at 1 Hz)of Yishu fault changes a little overall,but the segmentation characteristics is significant,that is the average Q_c value(34.95)in Laizhou Bay and its adjacent sea areas is significantly higher than that of other sections. The average Q_c value of the Weifang-Mengtuan section(23.22),Xinyi-Suqian section(21.12)is relatively low; ②The spatial distribution of the coda wave Q_c value is closely related to the structural characteristics of the regional crustal medium,which clearly revealed the attributionof Yishu fault as the structural boundary zone.