2008年5月12日汶川M_W7.9地震的震源位置与发震时刻
|
摘要
综合运用四川省地震台网与紫坪铺水库地震台网的观测资料,精确地测定了2008年5月12日汶川MW7.9地震的震源位置与发震时刻.指出,对汶川地震这样的大地震精准定位,必须克服或尽量减少远台观测对地震精确定位的局限性、地壳介质模型的不完善性以及识别与检测初至波震相的不一致性等因素的影响.通过分析对比、反复试验,从上述台网中精心选取了方位分布均匀、具有近震源台站约束、直达P波震相确系由初始破裂辐射出的15个地震台的直达P波到时数据,反演得出精确度比区域性地震台网常规测定的精确度高一个数量级的汶川大地震的定位结果,即:发震时刻(北京时间):2008年5月12日14:27:57.59±0.03s;震中位置:31.018°N±0.3km,103.365°E±0.3km;震源深度:15.5km±0.3km.
The hypocenter and origin time of the MW7.9 Wenchuan earthquake of May 12,2008,were relocated precisely using the observation data from both of the Sichuan Province Seismic Network and the Zhipinpu Reservoir Seismic Network.It is pointed out that the factors affected significantly to the precise and accurate determination of the hypocenter and origin time of the great earthquakes such as the Wenchuan earthquake are the limitation of far stations,incompleteness of the crust model used for earthquake location,and the inconsistency existed in the direct P phases detected from the near-by seismic stations and the far stations being generated from different rupture areas and at different times.To diminish the limitation caused by these factors,data from the local seismic stations were analyzed,and from these stations,15 near-by stations of epicentral distance of 5—160 km,with well azimuthal distribution,and with accurately correlated direct P phases were selected for inversion.The preferred relocated source parameters,obtained from inversion,have coordinates latitude 31.018°N±0.3 km,longitude 103.365°E±0.3 km,focal depth 15.5 km±0.3 km,origin time(Beijing Time) May 12,2008,14:27:57.59±0.03 s.
The hypocenter and origin time of the MW7.9 Wenchuan earthquake of May 12,2008,were relocated precisely using the observation data from both of the Sichuan Province Seismic Network and the Zhipinpu Reservoir Seismic Network.It is pointed out that the factors affected significantly to the precise and accurate determination of the hypocenter and origin time of the great earthquakes such as the Wenchuan earthquake are the limitation of far stations,incompleteness of the crust model used for earthquake location,and the inconsistency existed in the direct P phases detected from the near-by seismic stations and the far stations being generated from different rupture areas and at different times.To diminish the limitation caused by these factors,data from the local seismic stations were analyzed,and from these stations,15 near-by stations of epicentral distance of 5—160 km,with well azimuthal distribution,and with accurately correlated direct P phases were selected for inversion.The preferred relocated source parameters,obtained from inversion,have coordinates latitude 31.018°N±0.3 km,longitude 103.365°E±0.3 km,focal depth 15.5 km±0.3 km,origin time(Beijing Time) May 12,2008,14:27:57.59±0.03 s.
引文
①中国地震局．２００９．四川５·１２汶川８．０级地震科学总结与反思报告，第三章表３．１．１．
①中国地震局．２００９．四川５·１２汶川８．０级地震科学总结与反思报告，第三章表３．１．１．
陈九辉,刘启元,李顺成,郭凤焱,李昱,王峻,齐少华.2009.汶川MS8.0地震余震序列重新定位及其地震构造研究[J].地球物理学报,52(2):390-397.
陈培善.2008.全球大震和中国及邻区中强震地震活动(2008年4—5月)[J].地震学报,30(5):545-549.
陈运泰.2008.汶川地震的震源破裂过程[C]∥海峡两岸防震减灾学术研讨会,2008年6月27日—28日.北京:中国科学院:10-11.
黄媛,吴建平,张天中,张东宁.2008.汶川8.0级大地震及其余震序列重定位研究[J].中国科学:D辑,38(10):1242-1249.
刘启元,陈九辉,李顺成,李昱,郭凤焱,王峻,齐少华.2008.汶川MS8.0地震:川西流动地震台阵观测数据的初步分析[J].地震地质,30(3):584-596.
杨智娴.2003.地震定位[G]∥中国地震局监测预报司(编).地震参数:数字地震学在地震预测中的应用.北京:地震出版社:120-140.
杨智娴,陈运泰,苏金蓉,陈天长.2008.汶川大地震主震震源参数的初定情况报告[R].北京:北京大学-中国地震局现代地震科学技术研究中心.
赵珠,范军,郑斯华,长谷川昭,崛内茂木.1997.龙门山断裂带地壳速度结构和震源位置的精确修定[J].地震学报,19(6):615-622.
赵珠,张润生.1987a.四川地区地壳上地幔速度结构的初步研究[J].地震学报,9(2):154-166.
赵珠,张润生.1987b.四川地区分区走时表的编制[J].四川地震,(2):29-35.
Bormann P(ed).2006.New Manual of Seismological Observatory Practice[M].Vol.1and2:1-1003.
Geiger L.1910.Herdbestimming bei erdbeben aus ankunftszeiten[J].K Ges Wiss Got,4:331-349.
Herrmann R B,Ammon C J.2004.Computer Programs in Seismology:GSAC(Generic Seismic Application Coding)[CP].Version3.30.
Mooney W D,Prodehl C,Pavlenkova N I.2002.Seismic velocity structure of the continental lithosphere from controlledsource data[M]∥Lee W H K,Kanamori H,Jennings P C,Kisslinger C eds.International Handbook of Earth-quake and Engineering Seismology.Part A:887-910.
①中国地震局．２００９．四川５·１２汶川８．０级地震科学总结与反思报告，第三章表３．１．１．
陈九辉,刘启元,李顺成,郭凤焱,李昱,王峻,齐少华.2009.汶川MS8.0地震余震序列重新定位及其地震构造研究[J].地球物理学报,52(2):390-397.
陈培善.2008.全球大震和中国及邻区中强震地震活动(2008年4—5月)[J].地震学报,30(5):545-549.
陈运泰.2008.汶川地震的震源破裂过程[C]∥海峡两岸防震减灾学术研讨会,2008年6月27日—28日.北京:中国科学院:10-11.
黄媛,吴建平,张天中,张东宁.2008.汶川8.0级大地震及其余震序列重定位研究[J].中国科学:D辑,38(10):1242-1249.
刘启元,陈九辉,李顺成,李昱,郭凤焱,王峻,齐少华.2008.汶川MS8.0地震:川西流动地震台阵观测数据的初步分析[J].地震地质,30(3):584-596.
杨智娴.2003.地震定位[G]∥中国地震局监测预报司(编).地震参数:数字地震学在地震预测中的应用.北京:地震出版社:120-140.
杨智娴,陈运泰,苏金蓉,陈天长.2008.汶川大地震主震震源参数的初定情况报告[R].北京:北京大学-中国地震局现代地震科学技术研究中心.
赵珠,范军,郑斯华,长谷川昭,崛内茂木.1997.龙门山断裂带地壳速度结构和震源位置的精确修定[J].地震学报,19(6):615-622.
赵珠,张润生.1987a.四川地区地壳上地幔速度结构的初步研究[J].地震学报,9(2):154-166.
赵珠,张润生.1987b.四川地区分区走时表的编制[J].四川地震,(2):29-35.
Bormann P(ed).2006.New Manual of Seismological Observatory Practice[M].Vol.1and2:1-1003.
Geiger L.1910.Herdbestimming bei erdbeben aus ankunftszeiten[J].K Ges Wiss Got,4:331-349.
Herrmann R B,Ammon C J.2004.Computer Programs in Seismology:GSAC(Generic Seismic Application Coding)[CP].Version3.30.
Mooney W D,Prodehl C,Pavlenkova N I.2002.Seismic velocity structure of the continental lithosphere from controlledsource data[M]∥Lee W H K,Kanamori H,Jennings P C,Kisslinger C eds.International Handbook of Earth-quake and Engineering Seismology.Part A:887-910.
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