九江-瑞昌地震的精确定位及其发震构造初探  

Discussion on Precise Relocation and Seismo-tectonics of the Jiujiang-Ruichang Earthquake

作　　者：吕坚[1] 倪四道[1] 沈小七[2] 高建华 曾新福 

机构地区：[1]中国科学技术大学,合肥市金寨路230026 [2]安徽省地震局,合肥市230026 [3]江西省地震局,南昌市洪都北大道330039

出　　处：《中国地震》2007年第2期166-174,共9页Earthquake Research in China

基　　金：地震科学基金(A07124);中国地震局"数字地震资料在短临跟踪中的应用"项目(120602-06-114)

摘　　要：联合采用双差法和主事件法,对2005年11月26日发生在江西省九江县与瑞昌市交界的5.7级地震序列进行了重新定位,并在此基础上讨论了5.7级主震的震源机制解和可能的发震构造。结果显示:精定位后震源位置的估算误差在EW方向上平均为0.31km,NS方向上平均为0.40km,竖直方向上平均为0.48km,故而得到了更加精细的空间分布图像。此次地震序列在NNW-NW向呈现优势分布,震源深度主要集中在8～14km,又以10～12km最具优势。主震的震源位置大致为北纬29.69°,东经115.74°,震源深度约10.8km。结合地震序列优势分布、主震震源机制解和震区NE向、NW向断裂发育的构造背景,初步推测本次地震序列的主震可能是由瑞昌盆地内的一条NW向隐伏断层活动引发的,发震断层的性质有待于进一步研究。Based on relocating the Jiujiang-Ruichang earthquake sequence which occurred on 26 November, 2005 in Jiangxi Province with double-difference （DD） algorithm and master event technique, discuss focal mechanism of the main shock （Ms5.7） and the probable seismo-tectonics. The precise relocation results indicate that the average horizontal error is 0.31km in an EW direction and 0.40km in an NS direction, the average depth error is 0.48km. The focal depths vary from 8km to 14km, and with predominant distribution in 10 - 12km. The epicenter of the main shock is relocated to be 29.69°N, 115.74°E and the focal depth is about 10.8km. Combining the predominant distribution of earthquake sequence, the focal mechanism of the main shock and the tectonics condition of NE, NW faults growth in seismic region, we infer that the main shock of earthquake sequence is caused by an NW striking buried fault in the Ruichang basin, The nature of seismic faults needed to be further explored.

关 键 词：九江-瑞昌地震 双差地震定位法 主事件地震定位法 震源机制解 地震构造 

分 类 号：P315[天文地球—地震学]