祁连山中东段地区非弹性衰减系数、震源参数和场地响应研究

Study on Inelastic Attenuation Coefficient, Site Response and Source Parameters of the Middle-east Segment of Qilianshan Area

摘要:

利用甘肃数字地震台网的波形记录,基于遗传算法,首先用Atkinson方法计算非弹性衰减系数,在此基础上用Moya方法同时反演震源参数和场地响应。反演结果表明,祁连山中东段地区非弹性衰减Q值与频率的关系为:Q(f)=687.9f0.460;除了湟源台(HYQ)外,其余台站的场地响应均有不同程度的放大效应;研究区地震的应力降范围为2~40 bar,优势分布在2~20 bar;震源参数拐角频率与地震矩、地震矩与震级之间存在依赖关系。

Abstract:

Using digital seismograms recorded by Gansu digital seismic network, the inelastic attenuation coefficient is calculated based on genetic algorithm and the method proposed by Atkinson. Then, the site response and source parameters are inversed by Moya method. The inversion results indicate that the frequency-dependent of inelastic attenuation Q value in the middle-east segment of Qilianshan is estimated as ：Q（f）=687.9f^0.446. Excepting Huangyuan station, the site response at other stations show amplifications in different extent. The stress drops of all 28 earthquakes range between 0.2 to 4 MPa, dominantly distribute between 0.2 and 2 MPa. The dependence of corner frequency on seismic moment, seismic magnitude is also found.