2018年陕西宁强5.3级地震强地面运动特征及局部场地效应分析

2018年9月12日陕西省宁强县发生5.3级地震，中国数字强震动台网的39个专业台站在此次地震中触发。文章中通过处理捕获的117条三分向加速度记录，给出近场台站的地震动参数，绘制震中附近区域峰值加速度等值线图，其长轴呈西南-东北方向展布。采用实际观测数据与几种常用地震动衰减关系对比，发现霍俊荣衰减预测模型能更好地反映此次地震的影响场。将振幅最大的51GYD台的反应谱与我国抗震设计反应谱比较，采用最小二乘法拟合出不同震中距5个台站各周期谱加速度衰减特性，总结出此次地震的反应谱基本特征。运用H/V谱比法对51GYD土层台和62ZM台阵进行局部场地地震反应分析，研究覆盖土层对地震动的放大作用，及局部地形对峰值加速度和峰值速度的影响过程。

Characteristics of Strong Ground Motion of the 2018 Ningqiang M5.3 Earthquake in Shaanxi Province and Local Site Response Analysis

On September 12, 2018, a M5.3 earthquake occurred at Ningqiang County, Shaanxi Province. Thirty-nine strong motion stations located in this region were fully triggered by the main shock. A total of 117 records of three-component acceleration were obtained by NSMONS. In this paper, we first calculated the ground motion parameters of near-field stations and drew the contour map of peak accelerations near the epicenter. It is then found that the attenuation prediction model of Huo Jun-rong can better reflect the influence field of the earthquake by comparing the observed data with some commonly used ground motion prediction equations. Finally, we compared the acceleration response spectrum of 51GYD station with the design spectrum to summarize the basic characteristics of response spectra for this earthquake. The H/V spectral ratio method was applied to analyze the seismic response of the local site at 51GYD station and 62ZM array. Furthermore, the amplification effect of overburden soil on ground motion and the influence process of local topography on peak acceleration and peak velocity were studied.