2008年盈江5.9级地震序列震源参数研究*
杨晶琼,杨周胜,刘丽芳,苏有锦,张 森

(云南省地震局,昆明 650224)

震源参数; 遗传算法; 震源谱; 地震序列; 盈江5.9级地震

Study on the Source Parameters of the Yingjiang MS5.9 Earthquake Sequence in 2008
YANG Jing-qiong,YANG Zhou-sheng,LIU Li-fang,SU You-jing,ZHANG Sen

(Earthquake Administration of Yunnan Province,Kunming 650224,Yunnan,China)

source parameters,genetic algorithm,source spectra,earthquake sequence,Yingjiang MS 5.9 earthquake

备注

2008年8月21日在云南省盈江县发生了MS5.9地震。利用云南区域数字地震台网记录的ML≥2.5余震波形记录,通过对S波观测记录谱进行传播路径、场地响应和仪器响应等影响的逐一消除,得到了196个ML≥2.5地震的震源谱,进而根据Brune圆盘震源模型,利用遗传算法计算了地震矩、应力降、震源半径等震源参数,结果表明,该地震序列的地震矩在1012～1016 N·m间,与近震震级有很好的线性关系,与震源半径也呈线性关系; 应力降与近震震级有一定的线性趋势相关性; 拐角频率和地震矩之间有明显的依赖关系。

Yingjiang MS5.9 earthquake On August 21,2008 occurred in Yunnan.Using waveforms of the ML≥2.5 earthquakes recorded by Yunnan Regional Digital Network.By removing propagation,site and instrument effects from the displacement spectra of the S-wave recordings,we obtain the source parameters of 196 ML≥2.5 earthquakes based on the Brune disc model and Genetic algorithm,namely,the seismic moment M0,stress drop Δσ and rupture radius r.The results show that there is a good linear relation between M0(1012～1016 N·m)and local magnitude ML,M0 and rupture radius r.Δσ seems dependent on ML; fc increases with M0 decreasing according to the lgfc-M0 relation.