云南漾濞6.4级地震强地面运动三要素基本特征分析

Basic characteristics of the three elements of strong ground motion of the Yangbi M6.4 earthquake in Yunnan Province

2021年5月21日云南漾濞发生6.4级地震,中国数字化强震动观测网络在主震中捕获28组加速度数据。对84条三分向加速度记录进行常规处理,计算出对应的地震动参数,并绘制震中附近水平向PGA和PGV等值线图,结果显示其走向和形态与震后烈度调查结果相近。将实际观测的相对持时进行曲线回归,求得相关系数,并据此计算出Td(5%~95%)持时对应的震源持续时间在10.22~13.06 s间,与震源破裂过程反演结果基本一致。再通过分析近场6个台站记录的加速度反应谱,并与抗震设计谱比较,总结此次地震的频谱特性,为该区域抗震设防提供参考依据。

On May 21,2021,an M6.4 earthquake occurred at Yangbi county,Yunnan Province.28 groups of acceleration data were obtained by the CDSMON.In this paper,84 three-component acceleration records were processed,and corresponding ground motion parameters were calculated.Horizontal PGA and PGV contour maps near the epicenter were drawn,and the results showed that the trend and shape are similar to the results of post-earthquake intensity survey.The corresponding source duration of Td(5%-95%)is between 10.22 s and 13.06 s,which is basically consistent with the inversion results of source rupture process.To summarize the spectrum characteristics of the earthquake,the acceleration response spectra recorded by six typical stations were analyzed and compared with the seismic design spectrum.The study results can provide a reference for seismic fortification in the study area.