滇西南地区品质因子、场地反应与震源参数研究

为深入了解滇西南地区地震动影响因素特征，更好地服务于目标区的抗震设防工作与地震预测等相关研究，利用两步非参数化广义反演方法对滇西南地区2007—2019年242组三分量强震记录进行分析，通过对地表观测地震动在频域内的分离求解，给出了该地区0.5～20 Hz的品质因子经验关系，获得了26个强震台站在研究频段内的场地反应，并与HVSR法揭示的场地放大结果进行对比分析。基于网格搜索法确定了35次地震事件的地震矩M0、拐角频率fc及震源模型参数$ \gamma $，拟合得到了部分震源参数之间的定标关系。研究结果表明，滇西南地区品质因子Q值与频率的关系为Q=94.23f 0.43；相较于HVSR法，非参数化广义反演方法确定的场地反应整体偏高，但2种方法得到的场地反应谱形较一致；拐角频率、地震矩及应力降等震源参数互相具有一定依赖性。

Study on Quality Factor,Site Effect and Source Parameter in Southwest Yunnan

In order to deeply understand the characteristics of influence factors of ground motion in Southwest Yunnan, and better serve the related research of seismic fortification and earthquake prediction in the target area, 242 groups of three-component strong earthquake recordings in Southwest Yunnan from 2007 to 2019 were analyzed by using the two-step non-parametric generalized inversion method. By separating and solving the ground motions observed on the surface in frequency domain, the empirical relationship of the quality factors of 0.5 ~ 20 Hz in this area was given, and the site effect of 26 strong earthquake stations in the study frequency band were obtained, which were compared with the HVSR results. Based on the grid search method, the seismic moment M₀, corner frequency f_c and source model parameters of 35 seismic events are determined, and the calibration relationship among some source parameters is obtained by fitting. The results show that the relationship between Q value and frequency of quality factor in Southwest Yunnan is Q=94.23f 0.43. Compared with HVSR method, the site response determined by non-parametric generalized inversion method is generally higher, but the site effect spectra obtained by the two methods are consistent. The source parameters such as corner frequency, seismic moment and stress drop are mutually dependent.