新疆巴楚-伽师地区上地壳三维速度层析成像
|
摘要
利用近震层析成像方法和2003年新疆巴楚-伽师MS6.8地震走时资料反演得到了震区地下速度图像。结果表明:P波速度在地壳内5km以上表现出了较强的横向非均匀性,反映该区地表的沉积盖层介质特征;在5～22km深度内以NWW和NNE向共轭相交的高速异常带为主,周围速度相对较低。结合构造背景和震源机制解,认为这一区处于NW-SE向的右行走滑和NNE-SSW向的挤压应力双力偶作用下,使得发生的地震有一定的相似性。而NWW和NNE向非均匀性条带为应变能的积累和释放提供了基础,是这次地震发生的一个重要条件。结合宏观调查和石油资料,推断这次地震发生在塔里木盆地西部的一条NWW走向、北倾的巴什托普隐伏断裂上。
A detailed tomographic image of the upper crustal structure in Bachu-Jiashi area,Xinjiang Uygur Autonomous Region,is determined by using P-wave arrival time from the Bachu-Jiashi MS6.8 earthquake in 2003.The inversion results as following:Over 5 km depth in the region,P-velocity imaging shows strongly horizontal heterogeneity,reflecting characteristics of sedimentary cover;Between 5～14 km dpeth,P-velocity imaging suggests that there exist two high and conjugated velocity zone encircled with relative low velocity body,one trending NWW and the other NNE.Combined with tectonic background and focal mechanism solutions,it is holded that the character of earthquakes in this region is similar under the action of double-couple,one of which is along NW-SE right-lateral strike-slip couple,and the other is along NNE-SSW compressive stress.The NWW and NNE zone of heterogeneity provided the fundation for strain energy accumulation and release,and was an important condition for occurence of the Bachu-Jiashi earthquake.Combined the macro damage and isoseismic feature from field investigation and the study on petroleum seismic exploration,it is considered that this earthquake occurred on Bashitupu fults in western tarim basin,which trends along NWW and is north dipping.
A detailed tomographic image of the upper crustal structure in Bachu-Jiashi area,Xinjiang Uygur Autonomous Region,is determined by using P-wave arrival time from the Bachu-Jiashi MS6.8 earthquake in 2003.The inversion results as following:Over 5 km depth in the region,P-velocity imaging shows strongly horizontal heterogeneity,reflecting characteristics of sedimentary cover;Between 5～14 km dpeth,P-velocity imaging suggests that there exist two high and conjugated velocity zone encircled with relative low velocity body,one trending NWW and the other NNE.Combined with tectonic background and focal mechanism solutions,it is holded that the character of earthquakes in this region is similar under the action of double-couple,one of which is along NW-SE right-lateral strike-slip couple,and the other is along NNE-SSW compressive stress.The NWW and NNE zone of heterogeneity provided the fundation for strain energy accumulation and release,and was an important condition for occurence of the Bachu-Jiashi earthquake.Combined the macro damage and isoseismic feature from field investigation and the study on petroleum seismic exploration,it is considered that this earthquake occurred on Bashitupu fults in western tarim basin,which trends along NWW and is north dipping.
引文
[1]杨建思.2003年3月24日新疆伽师MS6.8地震现场考察报告[R].2003.
[1]沈军,陈建波,王翠,等.2003年2月24日新疆巴楚-伽师6.8级地震发震构造[J].地震地质,2006,28(2):205-212.
[2]Um J,Thurber C.A fast algorithm for two-point seismic ray trac-ing[J].Bulletin of the Seismological Society of America,1987,77:972-86.
[3]Zhao D,Hasegawa A,Kanamori H.Deep structure of Japan sub-duction zone as derived from local,regional and teleseismic events[J].J.Geophys.Res.,1994,99:22313-22329.
[4]Zhao D,Hasegawa A,Horiuchi S.Tomographic imaging of P and S wave velocity structure beneath northeastern Japan[J].Journal of Geophysical Research,1992,97:19909-28.
[5]Paige C,Saunders M.LSQR:An algorithmfor sparse linear equa-tions and sparse least squares[J].Association of Computational Mechanics Transactions and Mathematical Software,1982,8:43-71.
[6]刘启元,陈九辉,李顺成,等.新疆伽师强震群区三维地壳上地幔S波速度结构及其地震成因的探讨[J].地球物理学报,2000,43(3):356-367.
[7]张先康,赵金仁,张成科,等.米尔东北侧地壳结构研究[J].地球物理学报,2002,45(5),665-671.
[8]梅世蓉.地震前兆场物理模式与前兆时空分布机制研究(一)——坚固体孕震模式的由来与证据[J].地震学报,1995,17(3):273-282.
[9]王卫民,李丽,赵连锋,等.2003年2月24日新疆巴楚-伽师MS6.8级地震震源破裂过程研究[J].地球物理学报,2005,48(2):343-351.
[10]高国英,聂晓红,夏爱国.2003年伽师6.8级地震序列和震源机制的初步研究[J].中国地震,2004,20(2):179-186.
[11]朱令人,苏乃秦,杨马陵.1997年新疆伽师强震群及三次成功的临震预报[J].中国地震,1998,14(2):101-115.
[12]周仕勇,许忠淮,陈晓非.伽师强震群震源特征及震源机制力学成因分析[J].地球物理学报,2001,44(5):654-662.
[13]胥颐,刘福田,刘建华,等.天山地震带的地壳结构与强震构造环境[J].地球物理学报,2000,43(2):184-193.
[14]尹光华,蒋靖祥,穆桂金.2003年2月24日巴楚-伽师6.8级地震的构造背景初控[J].干旱区地理,2003,26(2):103-109.
[1]沈军,陈建波,王翠,等.2003年2月24日新疆巴楚-伽师6.8级地震发震构造[J].地震地质,2006,28(2):205-212.
[2]Um J,Thurber C.A fast algorithm for two-point seismic ray trac-ing[J].Bulletin of the Seismological Society of America,1987,77:972-86.
[3]Zhao D,Hasegawa A,Kanamori H.Deep structure of Japan sub-duction zone as derived from local,regional and teleseismic events[J].J.Geophys.Res.,1994,99:22313-22329.
[4]Zhao D,Hasegawa A,Horiuchi S.Tomographic imaging of P and S wave velocity structure beneath northeastern Japan[J].Journal of Geophysical Research,1992,97:19909-28.
[5]Paige C,Saunders M.LSQR:An algorithmfor sparse linear equa-tions and sparse least squares[J].Association of Computational Mechanics Transactions and Mathematical Software,1982,8:43-71.
[6]刘启元,陈九辉,李顺成,等.新疆伽师强震群区三维地壳上地幔S波速度结构及其地震成因的探讨[J].地球物理学报,2000,43(3):356-367.
[7]张先康,赵金仁,张成科,等.米尔东北侧地壳结构研究[J].地球物理学报,2002,45(5),665-671.
[8]梅世蓉.地震前兆场物理模式与前兆时空分布机制研究(一)——坚固体孕震模式的由来与证据[J].地震学报,1995,17(3):273-282.
[9]王卫民,李丽,赵连锋,等.2003年2月24日新疆巴楚-伽师MS6.8级地震震源破裂过程研究[J].地球物理学报,2005,48(2):343-351.
[10]高国英,聂晓红,夏爱国.2003年伽师6.8级地震序列和震源机制的初步研究[J].中国地震,2004,20(2):179-186.
[11]朱令人,苏乃秦,杨马陵.1997年新疆伽师强震群及三次成功的临震预报[J].中国地震,1998,14(2):101-115.
[12]周仕勇,许忠淮,陈晓非.伽师强震群震源特征及震源机制力学成因分析[J].地球物理学报,2001,44(5):654-662.
[13]胥颐,刘福田,刘建华,等.天山地震带的地壳结构与强震构造环境[J].地球物理学报,2000,43(2):184-193.
[14]尹光华,蒋靖祥,穆桂金.2003年2月24日巴楚-伽师6.8级地震的构造背景初控[J].干旱区地理,2003,26(2):103-109.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心