【摘要】 发展了一种根据单台垂向记录的地震直达P波的第一个周期信号,研究地震波传播路径中介质衰减频散特性的方法.为了更有效地提高P波频散测量的分辨率和信噪比水平,减小系统误差,使用了数据重采样技术.应用改进的多重滤波方法测定P波群速度延迟.根据线性滞弹性体松弛模型反演得到了介质品质因子Qm、95%置信水平下的测量误差及相关参数.对营口台记录的辽宁岫岩震群的研究结果表明①1999年11月9日开始出现高Qm值,高Qm值对应的地震集中在距营口台32~46km,明显偏离Qm随震中距增加的线性规律;②5.4级地震前平均Qm值为460,5.4级地震后至2000年1月12日5.1级地震之前Qm值为391,5.1级地震之后Qm值为204.更多还原

【Abstract】 A method for determining medium quality factor is developed on the basis of analyzing the dispersion of the arrived first period P wave. In order to enhance signal to noise ratio, improve the resolution in measurement and reduce systematic error we applied the data resampling technique. The group velocity delay of P wave was derived by using an improved multi-filtering method. Based on a linear viscoelastic relaxation model we deduced the medium quality factor Q_m , and associated error with 95% confidence level. Applying the method to the seismic record of the Xiuyan M5.4 earthquake sequence we obtained the following result: ① High Q_m started to appear from Nov.9, 1999. The events giving the deduced high Q_m value clustered in a region, with their epicenter distances being between 32 and 46 km from the Yingkou station. This Q_m versus distance observation obviously deviates from the normal trend of Q_m linearly increasing with distance. ② The average Q_m before the 29 Dec.1999 M5.4 earthquake is 460, while the average Q_m between the M5.4 event and the 12 Jan.2000 M5.1 earthquake is 391, and the average Q_m after the M5.1 event is 204.更多还原