2023年12月18日甘肃积石山6.2级地震强震动记录特征分析  

Characteristics of strong motion records of the Jishishan,Gansu,M_(S)6.2 earthquake on December 18,2023

作　　者：张卫东 贾璐 康斌龙 袁洁 王伟全 ZHANG Weidong;JIA Lu;KANG Binlong;YUAN Jie;WANG Weiquan(Gansu Earthquake Agency,Lanzhou 730000,Gansu,China)

机构地区：[1]甘肃省地震局,甘肃兰州730000

出　　处：《地震工程学报》2024年第4期888-898,共11页China Earthquake Engineering Journal

基　　金：甘肃省地震局科技发展基金(2022Q14)。

摘　　要：2023年12月18日,甘肃省临夏回族自治州积石山县发生6.2级地震。基于甘肃地震预警台网获取的此次地震强震动记录,完成基线校正、滤波等基本数据处理后计算出地震动相关参数,分析此次地震震中200 km内的幅值、反应谱和持时等重要特征,并绘制峰值加速度等相关参数空间分布图。结果表明:此次地震震中200 km内获取到的峰值加速度范围为1.2~1511.6 cm/s 2,峰值速度范围为0.1~85.9 cm/s,由于地形和场地影响,地震动峰值随着震中距的增大而衰减。将实际观测值与常用的五种衰减模型预测值进行对比,表明YU模型对甘肃积石山6.2级的预测结果要明显优于NGA-West2的四种模型,但五种衰减模型都明显低估了实际观测值的最大峰值。通过对比两个邻近震源台站的5%阻尼比加速度反应谱与设计谱,发现三分向高频成分加速度反应谱均远超过7度罕遇地震的设计谱,且反应谱峰值周期均在0.5 s以内。通过计算5%~75%和5%~95%两种重要持时,发现持时随着震中距的增大而增大,且与Afshari&Stewart 16预测方程均基本吻合。On December 18,2023,an M_(S)6.2 earthquake struck Jishishan County,Linxia Hui Autonomous Prefecture,Gansu Province,China.In this paper,the strong motion records of the earthquake obtained by the Gansu Earthquake Early Warning Network were analyzed.After the basic data processing,such as baseline correction and filtering,the related parameters of ground motion were then calculated.The amplitude,response spectrum,and important duration characteristics recorded within 200 km of the epicenter were examined,and the spatial distribution map of related parameters,such as peak acceleration,was illustrated.Results show that the peak acceleration within 200 km of the epicenter ranges from 1.2 to 1511.6 cm/s 2,and the peak velocity ranges from 0.1 to 85.9 cm/s.The peak value of ground motion decreases with the increase in epicentral distance due to the influence of topography and site.Comparison results of the observation and prediction values of five commonly used attenuation models reveal that the prediction result of the YU model for the Jishishan M_(S)6.2 earthquake is better than the four models of NGA-West2.However,these models underestimate the maximum peak value of actual observation values.The acceleration response spectra of two near-source stations(5%damping ratio)in severely damaged areas were compared with the design spectrum.The results indicate that the acceleration response spectra of high-frequency components at the two stations far exceed the design spectrum of a rare earthquake with 7-degree,and the peak periods of the response spectra are within 0.5 s.Moreover,the durations of 5%-75%and 5%-95%increase with the epicentral distance,which is consistent with the prediction equation of AFShari&Stewart 16.

关 键 词：积石山地震 强震动记录 幅值衰减 反应谱 持时 

分 类 号：P319[天文地球—固体地球物理学]