施甸盆地三维速度结构模型研究
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摘要
盆地对地震动的放大作用是地震工程的一个重要研究问题。由于计算能力的限制,早期的盆地地震动模拟主要采用二维模型,不能反映真实的盆地地震波传播。近年来,三维盆地地震动模拟成为盆地效应研究的主要方法。合理的三维盆地速度结构模型是研究的必要基础。施甸盆地是我国西南地区的典型小型盆地,其地震动研究对于探讨小型盆地地震动的分布规律具有重要意义。本文在施甸县城小区化的研究基础上,基于盆地内24个钻孔的土样和波速测量结果,探讨了盆地覆盖层的分布规律,给出了盆地内典型的第四纪覆盖层剖面。在此基础上建立了施甸盆地的三维速度结构模型,为研究历次地震中施甸盆地地震动异常和分析小型盆地地震动放大作用奠定了基础。
Strong ground motion amplification of the basin is an important problem of earthquake engineering.Owing to the limitation on the computational capability,2-D models are used in the simulation of basin strong motion in the early stage,which can not reflect the real wave propagation in the basin.Recently,3-D simulation becomes the main method in studying the basin effect,and a reasonable 3-D basin velocity structure model is the base of the numerical simulation.Since the Shidian basin is a typical small scale basin in the southwest China,the research on its strong motion distribution is important for analyzing the law of wave propagation in small scale basin.Based on the soil samples and wave velocity measuring results from 24 boreholes in the basin,the sediment distribution of Shidian basin is discussed in detail.Moreover,some typical stratigraphic sections and their velocity structures of the Shidian basin are also provided according to the 24 boreholes data,and the 3-D velocity structure model is established based on them.The 3-D velocity model can be used to study the repeatedly abnormal ground motions of previous earthquakes,and the model also provides a foundation for the study of small scale basin’s ground motion in the southwest area of China.
Strong ground motion amplification of the basin is an important problem of earthquake engineering.Owing to the limitation on the computational capability,2-D models are used in the simulation of basin strong motion in the early stage,which can not reflect the real wave propagation in the basin.Recently,3-D simulation becomes the main method in studying the basin effect,and a reasonable 3-D basin velocity structure model is the base of the numerical simulation.Since the Shidian basin is a typical small scale basin in the southwest China,the research on its strong motion distribution is important for analyzing the law of wave propagation in small scale basin.Based on the soil samples and wave velocity measuring results from 24 boreholes in the basin,the sediment distribution of Shidian basin is discussed in detail.Moreover,some typical stratigraphic sections and their velocity structures of the Shidian basin are also provided according to the 24 boreholes data,and the 3-D velocity structure model is established based on them.The 3-D velocity model can be used to study the repeatedly abnormal ground motions of previous earthquakes,and the model also provides a foundation for the study of small scale basin’s ground motion in the southwest area of China.
引文
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[6]Lee S J,Chen H W,Huang B S.Simulations of strong ground motion and 3D amplification effect in the Taipei Basin by using a composite grid fi-nite-difference method[J].Bull.Seismol.Soc.Am.,2008,98(3):1229-1242.
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[9]非明伦崔建文,赵永庆,等.施甸地震震害分析[J].地震研究,2002,25(2):192-199.FEI Minglun,CUI Jianwen,ZHAO Yongqing,et al.An analysis of seismic disasters for Shidian earthquake[J].Journal of Seismological Re-search,2002,25(2):192-199.(in Chinese)
[10]中国地震局工程力学研究所.施甸县城规划区抗震设防小区划[R].哈尔滨:中国地震工程力学研究所,1991.Isnstitute of Engineering Mechanics,China Earthquake Administration.Seismic microzonation of Shidian city[R].Haerbin:Institute of Engineer-ing Mechanics,CEA,1991.(in Chinese)
[2]Wald D J,Graves R W.The seismic response of the Los Angeles basin,California[J].Bull.Seismol.Soc.Am.,1998,88(2):337-356.
[3]Olsen K B.Site amplification in the Los Angeles Basin from three-dimensional modeling of ground motion[J].Bull.Seismol.Soc.Am.,2000,90(6B):S77-S94.
[4]Komatitsch D,Qinya Liu,Tromp J,et al.Simulations of ground motion in the Los Angeles basin based upon the spectral-element method[J].Bull.Seismol.Soc.Am.,2004,94(1):187-206.
[5]Pitarka A,Irikura K,Iwata T,et al.Three-dimensional simulation of the near-fault ground motion for the 1995 Hyogo-Ken Nanbu(Kobe),Ja-pan,earthquake[J].Bull.Seismol.Soc.Am.,1998,88(2):428-440.
[6]Lee S J,Chen H W,Huang B S.Simulations of strong ground motion and 3D amplification effect in the Taipei Basin by using a composite grid fi-nite-difference method[J].Bull.Seismol.Soc.Am.,2008,98(3):1229-1242.
[7]陈立德,赵维城.一九七六年龙陵地震[M].北京:地震出版社,1979.CHEN Lide,Zhao Weicheng.1976 LongLing earthquake[M].Beijing:Seismological Press,1979.(in Chinese)
[8]姜葵.1988年云南澜沧-耿马地震[M].昆明:云南大学出版社,1993.JIANG Kui.1988 Yunnan Langcang-Gengma earthquake[M].Kunming:Yunnan University Press,1993.(in Chinese)
[9]非明伦崔建文,赵永庆,等.施甸地震震害分析[J].地震研究,2002,25(2):192-199.FEI Minglun,CUI Jianwen,ZHAO Yongqing,et al.An analysis of seismic disasters for Shidian earthquake[J].Journal of Seismological Re-search,2002,25(2):192-199.(in Chinese)
[10]中国地震局工程力学研究所.施甸县城规划区抗震设防小区划[R].哈尔滨:中国地震工程力学研究所,1991.Isnstitute of Engineering Mechanics,China Earthquake Administration.Seismic microzonation of Shidian city[R].Haerbin:Institute of Engineer-ing Mechanics,CEA,1991.(in Chinese)
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