2000年云南姚安地震余震区的速度和衰减结构层析成像分析
|
摘要
文中根据2000年云南姚安6.5级地震后,流动数字化地震监测台网记录到的地震序列走时和波形资料,采用震源位置和速度结构联合反演的方法,反演了震源区的VP、VS和QS的三维结构。层析成像结果显示,姚安6.5级地震发生在低VP、高QS扰动异常的边缘,大部分余震均发生在高、低VP、QS过渡区域内。VP的低值异常表明姚安震区存在一条NWW向断裂带,且异常深度达到10 km左右。该文通过研究地震序列的分布特征并结合震源区速度结构和衰减结构的特点,进一步探讨了姚安地震的发震构造。
Three-dimensional VP,VS and QS structures in the focal area of the 2000 Yaoan M6.5 are obtained by the simultaneous inversion method of travel time and waveform data recorded by a temporary seismic network installed after the earthquakes.The tomography results show that the earthquake occurred at the brim of the area with low-VP and high-QS disturbance anomalies.Most of the aftershocks are in sandwiched VP and QS zones between higher and lower values.The obvious low-VP anomalies in the focal area demonstrate the existence of the NWW fault and the anomalies is down to the depth of about 10 km.The seismogenic structure of Yaoan earthquake area are further discussed by combining the characters of the aftershock distribution with the velocity and attenuation structures in the focal area.
Three-dimensional VP,VS and QS structures in the focal area of the 2000 Yaoan M6.5 are obtained by the simultaneous inversion method of travel time and waveform data recorded by a temporary seismic network installed after the earthquakes.The tomography results show that the earthquake occurred at the brim of the area with low-VP and high-QS disturbance anomalies.Most of the aftershocks are in sandwiched VP and QS zones between higher and lower values.The obvious low-VP anomalies in the focal area demonstrate the existence of the NWW fault and the anomalies is down to the depth of about 10 km.The seismogenic structure of Yaoan earthquake area are further discussed by combining the characters of the aftershock distribution with the velocity and attenuation structures in the focal area.
引文
[1]He Z Q,Ye T L,Su W.3-D velocity structure of the middle and upper crust in the Yunnan region,China[J].Pure Appl.Geophys,2005,162:2 355-2 368.
[2]Hansen S,Thurber C,Mandernach M,et al,Seismic Velocity and Attenuation Structure of the EastRift Zone and South Flank of Kilauea Volcano,Hawaii[J].Bulletin of the Seismological Society ofAmerica,2004,94(4):1 430-1 440.
[3]王伟君,陈凌,陈棋福,等.2003年大姚地震震中区的速度和衰减结构[J].地球物理学报,2007,50(3):116-125.
[4]滕吉文.康滇构造带岩石圈物理与动力学[M].北京:科学出版社,1994.
[5]邓起东,张培震,冉勇康等.中国活动构造基本特征[J].中国科学D辑,2002,45(12):1 020-1 030.
[6]王新岭,刘杰,张国民,等.姚安地震序列与永胜地震序列的高精度定位[J].中国地震,2005,21(3):386-397.
[7]胡鸿翔,陆涵行,王春镛,等.滇西地区地壳结构的爆破地震研究[J].地球物理学报,1986,29,(2):133-144.
[8]Thurber C.Earthquake locations and three-dimensional crustal structure in the Coyote Lake area,central California[J].J Geophys Res,1983,88:8 226-8 236.
[9]Zhao.Tomographic imaging of P and S wave velocity structure beneath northeastern Japan[J].JGeophys Res,1992a,97(B13):19 909-19 928.
[10]周龙泉,刘杰,陈晓非,等.2003年大姚6.2和6.1级地震前三维波速结构的演化[J].地震学报,2007,29(1):20-30.
[11]Junho Um,Clifford Thurber.A fast algorithm for two-point seismic ray tracing[J].Bulletin of Seis-mological Society of America,1987,77(3):972-986.
[12]Brune J N.Tectonic stress and spectra of seismic shear wave form earthquake[J].J Geophys Res,1970,75:4 997-5 009.
[13]Eberhart-Phillips D,Chadwick M.Three-dimensional attenuation model of the shallow Hikurangisubduction zone in the Raukumara Peninsula[J].New Zealand Geophys Res,2002,107:2033,doi:10.1029/2000JB000046.
[14]Goldberg D E.Genetic Algorithms in Search,Optimization and Machine Learning[M].Boston:Kluwer Academic Publishers,1989.
[15]郑建常,顾瑾平,张元生.联合反演研究华北地区三维速度结构[J].地球物理学进展,2007,22(6):1 706-1 714.
①云南省地质矿物局,大姚幅1 20万区域地质调查报告,1965年。
[2]Hansen S,Thurber C,Mandernach M,et al,Seismic Velocity and Attenuation Structure of the EastRift Zone and South Flank of Kilauea Volcano,Hawaii[J].Bulletin of the Seismological Society ofAmerica,2004,94(4):1 430-1 440.
[3]王伟君,陈凌,陈棋福,等.2003年大姚地震震中区的速度和衰减结构[J].地球物理学报,2007,50(3):116-125.
[4]滕吉文.康滇构造带岩石圈物理与动力学[M].北京:科学出版社,1994.
[5]邓起东,张培震,冉勇康等.中国活动构造基本特征[J].中国科学D辑,2002,45(12):1 020-1 030.
[6]王新岭,刘杰,张国民,等.姚安地震序列与永胜地震序列的高精度定位[J].中国地震,2005,21(3):386-397.
[7]胡鸿翔,陆涵行,王春镛,等.滇西地区地壳结构的爆破地震研究[J].地球物理学报,1986,29,(2):133-144.
[8]Thurber C.Earthquake locations and three-dimensional crustal structure in the Coyote Lake area,central California[J].J Geophys Res,1983,88:8 226-8 236.
[9]Zhao.Tomographic imaging of P and S wave velocity structure beneath northeastern Japan[J].JGeophys Res,1992a,97(B13):19 909-19 928.
[10]周龙泉,刘杰,陈晓非,等.2003年大姚6.2和6.1级地震前三维波速结构的演化[J].地震学报,2007,29(1):20-30.
[11]Junho Um,Clifford Thurber.A fast algorithm for two-point seismic ray tracing[J].Bulletin of Seis-mological Society of America,1987,77(3):972-986.
[12]Brune J N.Tectonic stress and spectra of seismic shear wave form earthquake[J].J Geophys Res,1970,75:4 997-5 009.
[13]Eberhart-Phillips D,Chadwick M.Three-dimensional attenuation model of the shallow Hikurangisubduction zone in the Raukumara Peninsula[J].New Zealand Geophys Res,2002,107:2033,doi:10.1029/2000JB000046.
[14]Goldberg D E.Genetic Algorithms in Search,Optimization and Machine Learning[M].Boston:Kluwer Academic Publishers,1989.
[15]郑建常,顾瑾平,张元生.联合反演研究华北地区三维速度结构[J].地球物理学进展,2007,22(6):1 706-1 714.
①云南省地质矿物局,大姚幅1 20万区域地质调查报告,1965年。
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