江苏及邻区地震波非弹性衰减Q值、场地响应和震源参数研究

Research on the Q­value，site response and seismic source parameters in Jiangsu and its adjacent areas

摘要:

根据江苏数字地震台网(包含邻区共享台站)73个数字地震台记录的49次地震事件的波形资料，用Atkinson方法对江苏地区的非弹性衰减Q值进行了计算，得到研究区介质非弹性衰减平均Q值随频率f的关系式为Q(f)＝272.1?f0.5575，并用Moya方法计算并得到了研究区内63个台站的场地响应。结果表明，江苏境内25个地面基岩台的场地响应为1～20Hz，放大倍数基本在1附近波动，符合基岩台基的特征。14个井下台站场地响应形态相同，表现为低频放大，高频部分迅速衰减。根据Brune模型计算并获得了江苏及邻区2010年10月至2015年3月58个ML2.5以上地震的震源参数，结果表明，近震震级与地震矩、震源尺度和拐角频率的相关性较好，而与应力降的关系不明显，且应力降与震源尺度的关系也不明显。

Abstract:

Based on 49 digital seismograms recorded on 73 seismic stations of Jiangsu Digital Seismic Network，the paper uses Atkinson's method to calculate the inelastic attenuation coefficient of the Jiangsu area. We find that the frequency-dependent Q in the Jiangsu region is. We also use Moya's method to invert the 63 stations' site responses. The results show that the site responses of the 25 stations in Jiangsu are approximately 1 at a range between 1Hz and 20Hz，which is consistent with their basements on rocks. The response curves of the site response of the 14 underground stations are similar to each other. Their site responses show an amplification at low frequencies and minification at high frequencies. The calculation of the Brune model on the waveform data of ML≥2.5 earthquakes from Jiangsu Digital Seismic Network between October 2010 and May 2015 in terms of seismic source parameters of 58 seismic waves shows that there is good correlations between seismic magnitude and other source parameters such as seismic moment，source radius and corner frequency，while the correlations between seismic magnitude and stress drop，the stress drop and source radius are not so good.