通过对2014年鲁甸MS6.5地震13个强震动台站观测记录的谱分析,估算了地震矩、矩震级等震源参数,得到的平均矩震级MW=6.3。讨论了震源Brune模型位移谱形状系数以及局部场地条件对估算参数的影响,结果显示,谱形状系数对参数估算影响不大,但ω2和ω3源谱模型分别能与远场和近场记录获取的源谱吻合更好;同时,仅在场地的卓越频率小于1 Hz时,场地条件影响参数的估算,由于13个台站均处于Ⅰ-Ⅱ类场地上,局部场地条件对本文参数计算结果影响不大。
Through spectrum analysis of observation recordings of Ludian MS6.5 earthquake in 2014 recorded by 13 strong motion station,we estimated the source parameters of the earthquake such as seismic moments,moment magnitude,corner frequency etc.and obtained the average moment magnitude MW=6.3.Then we discussed the influence of the displacement spectrum shape coefficients of the Brune source model and the local site condition on the source parameter estimation.The results show that the influence of the spectrum shape coefficients on the source parameter estimation is small,but source spectrum model ω2 and ω3 fit the source spectrums of recordings from far site and near-site separately.At the same time,only when the predominant site frequency is smaller than 1 Hz,the site condition could influence the source parameter estimation.The studied 13 stations are all located at I and II sites,so the local site condition does not influence the results of the source parameter estimation.