中亚地区上地幔 P 波速度结构特征探讨
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摘要: 用多重反射 P 波的走时研究了中国西北和中亚地区下部上地幔 P 波的速度结构的横向不均匀特征.其方法为用 WKBJ 法计算出70年代发生于中国大陆地区的7个大地震的 P波和 PP 波的理论地震图,而后求出其与观测波形的 PP 波减 P 波的走时残差.该残差值反映了震中至台站路径中点附近的上地幔速度结构.结果表明:位于苏联中亚地区的俄罗斯高原,图兰高原及西伯利亚高原西部地区下面的上地幔速度结构与加拿大地遁的情况相近;而中国西北部的褶皱带及苏联的中亚褶皱系统,哈萨克褶皱带下面的上地幔的 P 波速度较低.表明上地幔速度结构与地质构造有关.
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[1] 卓钰如，1991.不同震源机制地震PP波与P波振幅比特征的讨论.地震学报，13. 150——160.
[2] 卓钰如，Kanamori, H. , 1990.中国三个大地震的震源参数及讨论.地球物理学报，33. 489——496.
[3] Cara, M，1979. Lateral variation of S velocity in the upper mantle from higher Raylcigh modes. Geuphys. J. R. aslrun. Sue.，57. 649——670.
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[6] Dziewonshi, A. M.，1984. Mapping the lower mantle: determination of lateral heterogenity in P velocity up to de gree and order 6. J. Genphv.s. Re.s.，89. 5952——5959.
[7] Grand. S. P. and Helmberger, D. V., 1984. Upper mantle shear structure of north America. Geophys. J. R. aster. Soo. ,76, 399——438.
[8] Grand. S. P. and Helmberger. D. V., 1984. Uppermantle shear structure beneath Asia from multi——bounce Swaves. Physics of the Earth and Planetay Interiours, 41. 154——169.
[9] Jones, L. M，Han, W，Hauksson, E. . tin. A. , Zhang, Y. and Luo, Z, 1984. Focal mechanism and aftershock locanons of the Songpan earthquake of August 1976 in Sichuan. China. J. Geophvs. Res，89, 7679——7707.
[10] Lay, T.，1983. Localized velocity anomalids in the lower mantle. Geophys. J. R. a.str.，Soc.，72, 483——516.
[11] Lerner——Lam, A. L. and lordam, T. J.，1983. Earthquake structure from fundamental higher——mode wavefonn analysis. Geophvs. J. R. astr. Soc——75, 759——797.
[12] Nataf, H. C.，Nakanishi. 1. and Anderson, D. L.，1984. A note on lateral variation in upper mantle shearwavc velocity across the Alpine front. Geophvs. J. R. astr. Soc.，77, 639——645.[1] 卓钰如，1991.不同震源机制地震PP波与P波振幅比特征的讨论.地震学报，13. 150——160.
[2] 卓钰如，Kanamori, H. , 1990.中国三个大地震的震源参数及讨论.地球物理学报，33. 489——496.
[3] Cara, M，1979. Lateral variation of S velocity in the upper mantle from higher Raylcigh modes. Geuphys. J. R. aslrun. Sue.，57. 649——670.
[4] Chapman. C. H., 1978. A new methood for computing synthetic seismograms. Geuphys. J. Awtron., 57,649——670.
[5] Cipar, J.，1979. Source processes of the Haicheng China, earthquake from observation of P and S waves. Bull. .Seism. Soc., 69. 1903——1916.
[6] Dziewonshi, A. M.，1984. Mapping the lower mantle: determination of lateral heterogenity in P velocity up to de gree and order 6. J. Genphv.s. Re.s.，89. 5952——5959.
[7] Grand. S. P. and Helmberger, D. V., 1984. Upper mantle shear structure of north America. Geophys. J. R. aster. Soo. ,76, 399——438.
[8] Grand. S. P. and Helmberger. D. V., 1984. Uppermantle shear structure beneath Asia from multi——bounce Swaves. Physics of the Earth and Planetay Interiours, 41. 154——169.
[9] Jones, L. M，Han, W，Hauksson, E. . tin. A. , Zhang, Y. and Luo, Z, 1984. Focal mechanism and aftershock locanons of the Songpan earthquake of August 1976 in Sichuan. China. J. Geophvs. Res，89, 7679——7707.
[10] Lay, T.，1983. Localized velocity anomalids in the lower mantle. Geophys. J. R. a.str.，Soc.，72, 483——516.
[11] Lerner——Lam, A. L. and lordam, T. J.，1983. Earthquake structure from fundamental higher——mode wavefonn analysis. Geophvs. J. R. astr. Soc——75, 759——797.
[12] Nataf, H. C.，Nakanishi. 1. and Anderson, D. L.，1984. A note on lateral variation in upper mantle shearwavc velocity across the Alpine front. Geophvs. J. R. astr. Soc.，77, 639——645.
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