2017年九寨沟Ms7.0地震SmS震相观测与研究  

Observation and study on the SmS seismic phase generated by 2017 M_s7.0 Jiuzhaigou earthquake

作　　者：史晓宁 马强[1] 陶冬旺 SHI Xiaoning;MA Qiang;TAO Dongwang(Key Laboratory of Earthquake Engineering and Engineering Vibration,Institute of Engineering Mechanics,China Earthquake Administration,Harbin 150080,China)

机构地区：[1]中国地震局工程力学研究所,中国地震局地震工程与工程振动重点实验室,黑龙江哈尔滨150080

出　　处：《地震工程与工程振动》2018年第6期78-85,共8页Earthquake Engineering and Engineering Dynamics

基　　金：中国地震局工程力学研究所基本科研业务费专项资助项目(2016A03);国家重点研发计划资助项目(2017YFC1500802).

摘　　要：2017年8月8日在四川阿坝州九寨沟县发生了M_s 7.0地震。本文利用九寨沟地震中记录到的强震动数据,对震中距80～140 km范围内的台站的三分向记录进行SmS震相的识别,结合理论地震图的对比分析,确认了九寨沟地震中存在莫霍面反射的SmS震相。在特定的距离范围,SmS波振幅大,能量强,对地面运动有很强的控制作用。通过非参数回归方法对峰值加速度随距离的衰减进行回归,得到的回归曲线直观的显示了SmS波对PGA的影响,再结合时间窗搜索峰值加速度值,定量的确定了SmS波的振幅是直达Sg波的2～5倍。本文由此得出结论:在震中距80～140 km的超临界距离,莫霍面反射的SmS波对地震动峰值加速度有着明显的影响。The M_s 7.0 earthquake occurred in Jiuzhaigou County, Sichuan Province on August 8, 2017. In this article, we use strong ground motion records in Jiuzhaigou earthquake to identify the SmS phase within epicenter distance 80~140 km.With the comparative analysis of synthetic seismograms, we confirmed that there are Moho reflection SmS phase in this earthquake. At specific distance, the SmS phase’s amplitudes are large and the energy is strong, which has an intense influence on the ground motion. By nonparametric regression method to model the dependence of peak ground acceleration on epicenter distance, the regression curve shows the influence of SmS phase to PGA. Using time windows to search peak ground accelerations and determine the SmS wave’s amplitudes are 2~5 times than Sg wave. This article concludes that the Moho reflection SmS phase has obvious influence on the peak value of ground motion in the supercritical distance between 80~140 km.

关 键 词：九寨沟Ms7.0地震 SmS波 理论地震图 非参数回归 峰值加速度 

分 类 号：P315.9[天文地球—地震学] TU4[天文地球—固体地球物理学]