基于局部一维模型与走时标定的区域三维速度模型构建技术研究
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摘要
构建区域介质三维速度模型并以之获得准确的区域震相走时,是提高区域地震定位精度的重要手段之一.为充分利用已有的一维模型、GT事件、地质资料等实现三维模型构建,尝试基于目标区域内已有的部分局部一维模型,通过克里金空间插值建立初始三维模型,然后利用GT事件走时数据并参考其它地震地质资料对其不断进行修正,使得其走时偏差图与GT事件走时偏差图一致,进而获得能够提高区域地震定位精度的三维模型.使用不同模型进行的地震定位实验表明,以此方法建立的三维模型的定位偏差较初始模型减少约20%,较好地起到了减小区域震相走时残差,提高区域地震定位精度的作用.
Calculating accurate regional phase travel-times through regional 3D velocity models constructed is one of the important means to improve regional seismic event location accuracy. Using local 1D model, ground truth (GT) events and geological data, construction of 3D velocity model is carried out as follows: First, we construct an initial 3D velocity structure through Kriging method using some local 1D velocity models; then, modify it repeatedly by GT event travel-times and geological data until the minimum travel-time bias is reached; and finally, the modified 3D velocity model is obtained. Location testing is performed with different velocity models. It shows that the modified 3D velocity model can improve regional event location accuracy, and the bias of epicenters is decreased by about 20% statistically.
Calculating accurate regional phase travel-times through regional 3D velocity models constructed is one of the important means to improve regional seismic event location accuracy. Using local 1D model, ground truth (GT) events and geological data, construction of 3D velocity model is carried out as follows: First, we construct an initial 3D velocity structure through Kriging method using some local 1D velocity models; then, modify it repeatedly by GT event travel-times and geological data until the minimum travel-time bias is reached; and finally, the modified 3D velocity model is obtained. Location testing is performed with different velocity models. It shows that the modified 3D velocity model can improve regional event location accuracy, and the bias of epicenters is decreased by about 20% statistically.
引文
冯梅,安美建.2007.中国大陆中上地壳剪切波速结构[J].地震学报,29(4):337--347.
高锐,肖序常,刘训,管烨,李秋生,卢德源,李朋武.2001.新疆地学断面深地震反射剖面揭示的西昆仑—塔里木结合带岩石圈细结构[J].地球学报,22(6):547--552.
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贺日政,高锐,李秋生,管烨,李朋武.2001.新疆天山(独山子)—西昆仑(泉水沟)地学断面地震与重力联合反演地壳构造特征[J].地球学报,22(6):553--558.
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米宁,王良书,李华,徐鸣洁,李成,张勇,陈运平,于大勇.2005.天山和塔里木盆地结合部地壳上地幔速度结构[J].科学通报,50(4):363--368.
钱辉,许志琴,姜枚,宿和平.2006.西昆仑接收函数反演与构造解析[J].中国地质,33(2):309--316.
王有学,韩果花,姜枚.2004.阿尔泰—阿尔金地学断面地壳结构[J].地球物理学报,47(2):46--54.
胥颐,刘建华,刘福田.2006.天山—帕米尔结合带的地壳速度结构及地震活动研究[J].地球物理学报,49(6):1693--1700.
杨少敏,李杰,王琪.2008.GPS研究天山现今变形与断层活动[J].中国科学:D辑,38(7):872--880.
杨主恩,张先康,赵瑞武,周伟新.2005.天山中段的深浅构造[J].地震地质,27(1):11--19.
赵俊猛,李植纯,马宗晋.2003.天山分段性的地球物理分析[J].地学前沿,10(S1):125--131.
赵俊猛,程宏岗,裴顺平,刘宏兵,张健狮,刘宝丰.2008.塔里木盆地北缘的深部结构[J].科学通报,53(8):946--955.
周仕勇.1999.主地震定位法分析以及1997年新疆伽师强震群高精度定位[J].地震学报,21(3):43--51.
Cormier V F.2001.Construction of3-D earth models for station specific path corrections by dynamic ray tracing[C]∥Proceedings of the23rd Seismic Research Review.Tucson,Arizona,USA,NNSA,1:30--36.
Kennett B L N,Engdahl E R.1991.Travel times for global earthquake location and phase identification[J].Geophys JInt,105(3):429--465.
Kennett B L N,Engdahl E R,Buland R.1995.Constraints on seismic velocities in the Earth from travel times[J].Geophys J Int,122(1):108--124.
Russian Federation/United States Calibration Working Group.2002.Refinement of regional seismic event location innorthern Eurasia using3-D crustal and upper mantle velocity model[C]∥Proceedings of the24th Seismic ResearchReview.Tucson,Arizona,USA,NNSA,2:176--185.
Ryaboy V,Baumgardt D R,Firbas P,Dainty A M.2001.Application of3-D crustal and upper mantle velocity model ofNorth America for location of regional seismic events[J].Pure Appl Geophys,158(1):79--103.
Schneider W A,Ranzinger K A,Balch A H,Kruse C.1992.A dynamic programming approach to first arrival traveltimecomputation in media with arbitrarily distributed velocities[J].Geophysics,57(1):39--50.
Steck L K,Rowe C A,Begnaud M L,Phillips W S,Gee V L,Velasco A A.2004.Advancing seismic event locationthrough difference constraints and three-dimensional models[C]∥Proceedings of the26th Seismic Research Review.Tucson,Arizona,USA,NNSA,3:346--355.
高锐,肖序常,刘训,管烨,李秋生,卢德源,李朋武.2001.新疆地学断面深地震反射剖面揭示的西昆仑—塔里木结合带岩石圈细结构[J].地球学报,22(6):547--552.
高锐,肖序常,高弘.2002.西昆仑—塔里木—天山岩石圈深地震探测综述[J].地质通报,21(1):11--18.
贺日政,高锐,李秋生,管烨,李朋武.2001.新疆天山(独山子)—西昆仑(泉水沟)地学断面地震与重力联合反演地壳构造特征[J].地球学报,22(6):553--558.
姜枚,许志琴,薛光琦,史大年.1999.青海茫崖—新疆若羌地震探测剖面及其深部构造的研究[J].地质学报,73(2):153--161.
李海鸥,姜枚,王亚军,张立树,于更新.2006.新疆富蕴—库尔勒剖面接收函数方法获得的地壳上地幔结构成像[J].地质学报,80(1):135--141.
李秋生,卢德源,高锐.2001.新疆地学断面(泉水沟—独山子)深地震探测成果综合研究[J].地球学报,22(6):534--540.
李顺成,刘启元,陈九辉,郭飙,赖院根,王继.2005.横跨天山的宽频带流动地震台阵观测[J].地球物理学进展,20(4):955--960.
米宁,王良书,李华,徐鸣洁,李成,张勇,陈运平,于大勇.2005.天山和塔里木盆地结合部地壳上地幔速度结构[J].科学通报,50(4):363--368.
钱辉,许志琴,姜枚,宿和平.2006.西昆仑接收函数反演与构造解析[J].中国地质,33(2):309--316.
王有学,韩果花,姜枚.2004.阿尔泰—阿尔金地学断面地壳结构[J].地球物理学报,47(2):46--54.
胥颐,刘建华,刘福田.2006.天山—帕米尔结合带的地壳速度结构及地震活动研究[J].地球物理学报,49(6):1693--1700.
杨少敏,李杰,王琪.2008.GPS研究天山现今变形与断层活动[J].中国科学:D辑,38(7):872--880.
杨主恩,张先康,赵瑞武,周伟新.2005.天山中段的深浅构造[J].地震地质,27(1):11--19.
赵俊猛,李植纯,马宗晋.2003.天山分段性的地球物理分析[J].地学前沿,10(S1):125--131.
赵俊猛,程宏岗,裴顺平,刘宏兵,张健狮,刘宝丰.2008.塔里木盆地北缘的深部结构[J].科学通报,53(8):946--955.
周仕勇.1999.主地震定位法分析以及1997年新疆伽师强震群高精度定位[J].地震学报,21(3):43--51.
Cormier V F.2001.Construction of3-D earth models for station specific path corrections by dynamic ray tracing[C]∥Proceedings of the23rd Seismic Research Review.Tucson,Arizona,USA,NNSA,1:30--36.
Kennett B L N,Engdahl E R.1991.Travel times for global earthquake location and phase identification[J].Geophys JInt,105(3):429--465.
Kennett B L N,Engdahl E R,Buland R.1995.Constraints on seismic velocities in the Earth from travel times[J].Geophys J Int,122(1):108--124.
Russian Federation/United States Calibration Working Group.2002.Refinement of regional seismic event location innorthern Eurasia using3-D crustal and upper mantle velocity model[C]∥Proceedings of the24th Seismic ResearchReview.Tucson,Arizona,USA,NNSA,2:176--185.
Ryaboy V,Baumgardt D R,Firbas P,Dainty A M.2001.Application of3-D crustal and upper mantle velocity model ofNorth America for location of regional seismic events[J].Pure Appl Geophys,158(1):79--103.
Schneider W A,Ranzinger K A,Balch A H,Kruse C.1992.A dynamic programming approach to first arrival traveltimecomputation in media with arbitrarily distributed velocities[J].Geophysics,57(1):39--50.
Steck L K,Rowe C A,Begnaud M L,Phillips W S,Gee V L,Velasco A A.2004.Advancing seismic event locationthrough difference constraints and three-dimensional models[C]∥Proceedings of the26th Seismic Research Review.Tucson,Arizona,USA,NNSA,3:346--355.
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