浙江地区Lg波路径衰减关系及台站场地响应参数

Lg-wave attenuation relationship and site response of stations in Zhejiang area

基于浙江省数字地震台网2007—2012年记录的台湾地区355次MS≥4.0地震的波谱比数据,使用场地响应与路径衰减联合反演的方法,对穿越台湾海峡特定路径的Lg波衰减关系及浙江地区36个测震台站的场地响应参数进行了计算.计算中选取频率为1—7 Hz、间隔为0.2Hz,计算得到了三分向(U--D,N--S,E--W)的衰减关系及场地响应参数.三分向衰减参数关系为γUD(f)=0.005 5f0.94,γNS(f)=0.006 4f1.11和γEW(f)=0.004 8f0.90.浙江地区36个台站均获得了稳定的场地响应,其中庆元台在高频端表现出较明显的放大效应,其它台站在所研究的频率范围内各分向场地响应大致相当,并未显示出明显的方向性特征.最后对场地响应的异常部分进行了具体分析和验证,表明本文计算结果正确可靠.

Based on the spectral ratio data, the Lg-wave attenuation relationship along a specific path across Taiwan Strait and the site response from 36 stations in Zhejiang area were calculated by using the joint inversion method of field response and the path attenuation. We used the data of 355 Ms≥4. 0 earth- quakes during the period of 2007--2012, which were recorded by Zhejiang digi- tal seismic network in Taiwan region. During the calculation process, the data in the frequency range of 1-7 Hz were selected with the interval of 0.2 Hz. The attenuation relationships are γUD （f） = 0. 005 5f0.94,γNS （f） = 0. 006 4f 1.11 and γEW（f）=0. 0048f0.9. in U-D, N-S and E-W direction. The site response at high-frequency end of Qingyuan station showed an obvious amplification effect, meanwhile, the site response of the other 35 stations are nearly equalwithout obvious direction characteristic. Furthermore, the abnormal results were analyzed and verified, suggesting the results in this paper be correct and reliable.