2010年广西凌云与凤山交界震群尾波Q值特征研究

2010年6月28日至8月初,广西凌云与凤山交界地区出现一次罕见的震群活动.利用震区附近8个近距离台站所记录的数字地震波形,按照高信噪比和计算要求,挑选出此次震群中74次ML＞1.5地震可用于计算地震尾波的共179条三分向波形记录,采用Sato单次散射模型经滤波以及消除环境噪声后,计算了地震尾波传播过程途经区的品质因子...

Q-value Characteristics of Seismic Coda about the Earthquake Swarm Occurred in Junction Area between Lingyun County and Fengshan County of Guangxi Zhuang Autonomous Region in 2010

During June 28 to early August in 2010, a small earthquake swarm occurred in the junction area between Lingyun County and Fengshan County, Guangxi Zhuang autonomous region. Based on the digital seismic waveforms recorded at 8 near-field seismic stations, 179 three-component records in 74 M_L>1.5 earthquakes selected according to the high signal-to-noise ratio and calculation requirements, after filtering the seismic waveform record to eliminate background noise by using the Sato single scattering model, we calculated the coda Q(f) and obtained the relationship between coda Q(f) and frequency (f) to be Q(f)=(44.32±23.56)f^0.88±0.17 in the studied area. Then, the spatiotemporal characteristics of seismic wave attenuation in source region and its adjacent regions are discussed. Analysis on the relationship between attenuation parameters and sampling depth of the seismic region and its adjacent areas suggests that there may exist shallow high attenuation layers beneath the study region. The earthquake swarm occurred at low stress levels, with higher Q₀ value and slower seismic wave attenuation in the source area than that of other stations, which suggests that the level of non-uniformity properties of the crustal medium is low in the source area with stable medium and slow attenation.