福建仙游地震序列尾波Qc值特征  

On Characteristics of Coda Q_c in the Xianyou Earthquake Sequence of Fujian Province

作　　者：李强[1] 李军[1] 袁丽文[1] 邱毅[1] 

机构地区：[1]福建省地震局,福州市350003

出　　处：《大地测量与地球动力学》2016年第2期184-188,共5页Journal of Geodesy and Geodynamics

基　　金：中国地震局青年震情跟踪课题(201501011)

摘　　要：利用Sato单次散射模型和莆田荔城台的近场数字地震记录,研究仙游地震序列尾波Q_c值的变化特征,并拟合得到整个序列的Q_c值随频率的变化关系为Q_c=(29.85±7.66)f(0.993±1.03)。仙游地震序列ML4.0以上显著地震事件发生前,1Hz的Q_c值以增大为主要特征,当Q_c值超过40,在随后的一段时间均有显著地震事件发生,映震效果相对明显;6Hz和12Hz的Q_c值与显著地震事件关系不明显。分析认为,显著地震事件发生前,震源区应力状态改变,导致介质散射程度变化明显。由于散射衰减机制主要在相对低频部分起重要作用,利用低频部分的Q_c值,更有利于识别出显著地震前的这种变化特征。Using the Sato single scattering model and the digital waveform recorded at PTLC station,we investigate the variation in coda Qcin the Xianyou earthquake sequence.We fit the Qcfrequencydependent relation for the whole earthquake sequence as Qc=（29.85±7.66）f（0.993±1.03）.The results show that Qcat 1Hz is characterized mainly as increasing prior to the ML≥4.0distinct earthquake events,and that the corresponding relations are distinct.Distinct earthquake events will occur when Qc is greater than 40.However,the relation between Qcat 6Hz or 12 Hz and distinct earthquake events is unclear.We consider that the changes in intensity of scattering attenuation of the medium arise due to changes in the state of stress in the focal zone.Because the scattering attenuation plays an important role in the attenuation mechanism at lower frequencies,Qcat lower frequency bands may be helpful to identify these characteristic＇s variations.

关 键 词：地震尾波 仙游地震 SATO模型 QC值 地震活动 

分 类 号：P315[天文地球—地震学]