基于克里金方法的区域震相走时标定技术研究
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摘要
在台网比较稀疏的情况下,台站走时标定是提高低震级事件定位、识别能力的重要手段.为了提高稀疏台网的定位精度,首先利用标定事件和IASPEI1991走时表以及中国大陆走时表,计算了初至P波和Lg波到AAK,MAKZ,NIL,TLG以及WMQ等5个台站的走时残差;接着,采用非平稳贝叶斯克里金方法和走时残差数据构造上述台站的走时校正曲面;最后,通过加入和不加入走时校正定位一系列位置准确的发生在新疆地区的地震事件评估克里金走时校正的有效性.结果表明,克里金走时校正能够较大地提高稀疏台网的定位精度,同时有效地缩小误差椭圆的面积.
Calibrating travel times of seismic phases recorded at specific stations is an important means to improve event location and discriminating low-magnitude seismic events recorded by a sparse station network.In an effort to improve sparse network event location,we firstly calculate first arrival P-wave and Lg-wave travel-time residuals for the calibration events relative to the IASPEI1991 or Mainland China velocity model at stations AAK,MAKZ,NIL,TLG and WMQ.We then use the residual data and non-stationary Bayesian Kriging approach to form continuous travel-time correction surfaces for the above mentioned stations.Lastly,the effectiveness of the Kriging interpolated travel-time correction surfaces is evaluated by locating,with and without corrections,a series of seismic events which occurred in Xinjiang Uygur Autonomous Region and have already had accurate locations.Results obtained show that the Krigged correction surfaces can improve the accuracy of event location by a sparse network and reduce the area of confidence ellipses effectively.
Calibrating travel times of seismic phases recorded at specific stations is an important means to improve event location and discriminating low-magnitude seismic events recorded by a sparse station network.In an effort to improve sparse network event location,we firstly calculate first arrival P-wave and Lg-wave travel-time residuals for the calibration events relative to the IASPEI1991 or Mainland China velocity model at stations AAK,MAKZ,NIL,TLG and WMQ.We then use the residual data and non-stationary Bayesian Kriging approach to form continuous travel-time correction surfaces for the above mentioned stations.Lastly,the effectiveness of the Kriging interpolated travel-time correction surfaces is evaluated by locating,with and without corrections,a series of seismic events which occurred in Xinjiang Uygur Autonomous Region and have already had accurate locations.Results obtained show that the Krigged correction surfaces can improve the accuracy of event location by a sparse network and reduce the area of confidence ellipses effectively.
引文
潘常周,靳平,肖卫国.2007.利用克里金技术标定新疆及附近地区P/S幅值比及其在地震事件识别中的应用[J].地震学报,29(6):625--635.
胥颐,刘福田,刘建华.2000.中国大陆西北造山带及其毗邻盆地的地震层析成像[J].中国科学:D辑,30(2):113--122.
王广平,吴广涛,伦志强,朱玉瑛.1982.新疆维吾尔自治区区域地质志[M].北京:地质出版社:728.
国家地震局地球物理研究所.1980.震相走时便查表[M].北京:地震出版社:876.
Bondr I,Ryaboy V.1997.Regional travel-ti me tables for the Baltic shield region[R].Center for Monitoring Research,Technical Report CMR-97/24:3--5.
Bondr I,Yang X,McLaughlin K,North R G,Ryaboy V,Nagy W.1998.Source specific station corrections for region-al phases at I MS stations in North America and Fennoscandia[J].EOS,79(45):555.
Bondr I,North R G,Beall G.1999Teleseismic slowness-azi muth station corrections for the International MonitoringSystemseismic network[J].Bull Seism Soc Amer,89(4):989--1003.
Cogbill A,Steck L K.1997.The use of propagation path corrections toi mprove seismic event locationin Western China[R].Los Alamos National Laboratory Report,LA-UR-97-4876:47.
Hartse H E.1998.The August1997Novaya Zemlya seismic event as viewed from GSN stations KEV and KBS[J].SeismRes Lett,69(3):206--215.
Jordan T H,Sverdrup K A.1981.Teleseismic location techniques and their application to earthquake clusters in thesouth-central pacific[J].Bull Seism Soc Amer,71(4):1105--1130.
Kennett B L N.1991.IASPEI1991Seismological Tables[M].Research School of Earth Sciences,Austalian NationalUniversity:167.
Matheron G.1965.Principles of geostatistics[J].Economic Geol,58(8):1246--1266.
Myers S C,Schultz C A.2000.I mproving sparse network seismic location with Bayesian Kriging and teleseismically con-strained calibration events[J].Bull Seism Soc Amer,90(1):199--211.
Nagy HJ.1996.Newregion-dependent travel-ti me handlingfacilities at the IDC:Functionality,Testing,andI mplemen-tation Details[R].Tech Rep SAIC-96/1179:57.
Nikolai A Vasiliev.2000.Methods for the I MS regional kinematic calibration[C/OL]∥Proceedings ofthe22nd AnnualDoD/DoESeismic Research Symposium:Plan for Verification of and Compliance withthe Comprehensive Nucle-ar-Test-Ban Treaty Treaty.02-49[2000-09-13].https:∥na22.nnsa.doe.gov/cgi-bin/prod/.researchreview/index.cgi.
Richards P G,Ki m W Y.1997.Testing the nuclear test-ban treaty[J].Nature,389:781--782.
Ryaboy V,Baumgardt D R,Firbas P,Dainty A M.2001.Application of3-Dcrustal and upper mantle velocity model ofNorth America for location of regional seismic events[J].Pure Appl Geophy,158:79--103.
Schultz C A,Stephen C M,Hipp J,Young CJ.1998Nonstationary Bayesian kriging:Apredictive technique to generatespatial corrections for seismic detection,location andidentification[J].Bull Seism Soc Amer,88(5):1275--1288.
Srivastava H,Isaaks E.1989.AnIntroductionto Applied Geostatistics[M].New York:Oxford University Press:561.
Sweeney.1996.Accuracy of teleseismic event locations in the Middle East and North Africa[R].Lawrence LivermoreNational Laboratory,UCRL-ID-125868:19.
Steck L K,Begnaud ML,Velasco A A.2001.Onthe use of kriged P-wave travel-ti me correction surfaces for seismiclo-cation[C/OL]∥23nd Annual DoD/DoE Seismic Research Symposium:Proceedings of the23rd Seismic ResearchReview:Worldwide Monitoring of Nuclear Explosions.02-30[2001-10-02].https:∥na22.nnsa.doe.gov/cgi-bin/prod/researchreview/index.cgi.
Waldhauser F,Richards P.2004.Reference events and empirical Source Specific Station Corrections for regional phasesat I MS stations in China[J].Bull Seism Soc Amer,94(6):2265--2279.
胥颐,刘福田,刘建华.2000.中国大陆西北造山带及其毗邻盆地的地震层析成像[J].中国科学:D辑,30(2):113--122.
王广平,吴广涛,伦志强,朱玉瑛.1982.新疆维吾尔自治区区域地质志[M].北京:地质出版社:728.
国家地震局地球物理研究所.1980.震相走时便查表[M].北京:地震出版社:876.
Bondr I,Ryaboy V.1997.Regional travel-ti me tables for the Baltic shield region[R].Center for Monitoring Research,Technical Report CMR-97/24:3--5.
Bondr I,Yang X,McLaughlin K,North R G,Ryaboy V,Nagy W.1998.Source specific station corrections for region-al phases at I MS stations in North America and Fennoscandia[J].EOS,79(45):555.
Bondr I,North R G,Beall G.1999Teleseismic slowness-azi muth station corrections for the International MonitoringSystemseismic network[J].Bull Seism Soc Amer,89(4):989--1003.
Cogbill A,Steck L K.1997.The use of propagation path corrections toi mprove seismic event locationin Western China[R].Los Alamos National Laboratory Report,LA-UR-97-4876:47.
Hartse H E.1998.The August1997Novaya Zemlya seismic event as viewed from GSN stations KEV and KBS[J].SeismRes Lett,69(3):206--215.
Jordan T H,Sverdrup K A.1981.Teleseismic location techniques and their application to earthquake clusters in thesouth-central pacific[J].Bull Seism Soc Amer,71(4):1105--1130.
Kennett B L N.1991.IASPEI1991Seismological Tables[M].Research School of Earth Sciences,Austalian NationalUniversity:167.
Matheron G.1965.Principles of geostatistics[J].Economic Geol,58(8):1246--1266.
Myers S C,Schultz C A.2000.I mproving sparse network seismic location with Bayesian Kriging and teleseismically con-strained calibration events[J].Bull Seism Soc Amer,90(1):199--211.
Nagy HJ.1996.Newregion-dependent travel-ti me handlingfacilities at the IDC:Functionality,Testing,andI mplemen-tation Details[R].Tech Rep SAIC-96/1179:57.
Nikolai A Vasiliev.2000.Methods for the I MS regional kinematic calibration[C/OL]∥Proceedings ofthe22nd AnnualDoD/DoESeismic Research Symposium:Plan for Verification of and Compliance withthe Comprehensive Nucle-ar-Test-Ban Treaty Treaty.02-49[2000-09-13].https:∥na22.nnsa.doe.gov/cgi-bin/prod/.researchreview/index.cgi.
Richards P G,Ki m W Y.1997.Testing the nuclear test-ban treaty[J].Nature,389:781--782.
Ryaboy V,Baumgardt D R,Firbas P,Dainty A M.2001.Application of3-Dcrustal and upper mantle velocity model ofNorth America for location of regional seismic events[J].Pure Appl Geophy,158:79--103.
Schultz C A,Stephen C M,Hipp J,Young CJ.1998Nonstationary Bayesian kriging:Apredictive technique to generatespatial corrections for seismic detection,location andidentification[J].Bull Seism Soc Amer,88(5):1275--1288.
Srivastava H,Isaaks E.1989.AnIntroductionto Applied Geostatistics[M].New York:Oxford University Press:561.
Sweeney.1996.Accuracy of teleseismic event locations in the Middle East and North Africa[R].Lawrence LivermoreNational Laboratory,UCRL-ID-125868:19.
Steck L K,Begnaud ML,Velasco A A.2001.Onthe use of kriged P-wave travel-ti me correction surfaces for seismiclo-cation[C/OL]∥23nd Annual DoD/DoE Seismic Research Symposium:Proceedings of the23rd Seismic ResearchReview:Worldwide Monitoring of Nuclear Explosions.02-30[2001-10-02].https:∥na22.nnsa.doe.gov/cgi-bin/prod/researchreview/index.cgi.
Waldhauser F,Richards P.2004.Reference events and empirical Source Specific Station Corrections for regional phasesat I MS stations in China[J].Bull Seism Soc Amer,94(6):2265--2279.
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