地震波各向异性：窥测地球深部构造的“探针”

doi:10.11867/j.issn.1001-8166.2005.09.0946

地震波各向异性日益成为不可忽视的地质地球物理现象。地球内部不同圈层（地壳、地幔和地核）都存在着地震波各向异性，并表现为不同的规模（小到单矿物和岩石，大到地体甚至上地幔）和强度。通过地震波各向异性可以间接获取岩石圈厚度、地球深部结构与构造变形、地球动力学和地幔对流等信息。主要从地震波各向异性的表现形式、原因及地质地球物理意义等方面对近年来大洋俯冲带、大陆裂谷、地幔转换带和大陆碰撞造山带（青藏高原）等构造环境中的研究成果进行了评述，讨论了各向异性[JP2]研究中需要重视的几个问题：①剪切波分辨率；②矿物组构研究；③其它各向异性成因机制。还强调了各向异性研究与流变学、高温高压岩石物理实验相结合的新方向。

关键词: 青藏高原, 地震波各向异性, 俯冲带, 大陆裂谷, 地幔转换带

Seismic anisotropy has received a lot of attention from seismologists in recent years and is becoming increasingly important in the field of geophysics and geology. It is regarded as the bridge between seismology and structural geology. Seismic anisotropy is discovered at all scales in the Earth's interior and may provide us with valuable information, such as the thickness and structure of lithosphere, mantle convection, and geodynamics, and since the fast wave propagation directions of shear wave correspond to flow directions as implied from plate motions, it is recognized as a good indicator of deformation and mantle flow. Seismic anisotropy plays a central role in revealing the deep structure and geodynamics in the following geological settings, such as subduction zone, continental rift, mantle transition zone and continental collisional orogenic belt (for instance, Tibet). This paper mainly reviews recent studies of the occurrence, geological interpretation and implication of seismic anisotropy for these geological settings. There is no doubt that the existing technologies will be refined and developed further to make estimates of anisotropy and related rock properties more accurate. Problems required to be further considered include the following: (1) resolution of shear wave: SKS wave is poor in vertical resolution, and it is suggested that the combination of surface wave and SKS wave may well constrain the depth of anisotropy; (2) petrofabric analysis: although great advances had been made in investigation of relationship between anisotropy and petrofabric, recent studies reveal that olivine fabric may be different from previously expected under water-rich conditions, which may then induce anomalous seismic anisotropy. Thus, efforts are still required to be taken to further study the petrofabric, and (3) other mechanisms for seismic anisotropy, such as MPO, aligned cracks, etc.. In particular, strain aligns highly anisotropic minerals, such as olivine, orthopyroxene, plagioclase, and so on, in the mantle and crust to form LPO, which is the most likely cause of splitting measured from records of distant earthquakes. As a result, it is emphasized that investigation of seismic anisotropy shall be combined with rheology of rocks and minerals at high temperature and pressure.

Key words: Continental rift, Tibet., Mantle transition zone, Seismic wave anisotropy, Subduction zone

中图分类号:

P315.3+1

[1] Hess H H. Seismic anisotropy of the uppermost mantle under oceans[J]. Nature, 1964, 203: 629-631.
[2] Rabbel W, Mooney W D. Seismic anisotropy of the crystalline crust: What does it tell us?[J].Terra Nova, 1996, 8: 16-21.
[3] Vinnik L P, Makeyeva L I, Milev A, et al. Global patterns of azimuthal anisotropy and deformations in the continental mantle[J]. Geophysical Journal International,1992, 111: 433-447.
[4] Poirier J P, Price G D. Primary slip system of ε-iron and anisotropy of the Earth's inner core [J]. Physics of the Earth and Planetary Interiors, 1999, 110: 147-156.
[5] Jin Zhenmin, Ji Shaocheng, Jin Shuyan. Lattice preferred orientation of olivines and seismic anisotropy in the upper mantle [J]. Acta Geophysica Sinica,1994, 37 (4): 469-477. [金振民, 嵇少丞, 金淑燕.橄榄石晶格优选方位和上地幔地震波速各向异性[J]. 地球物理学报, 1994, 37 (4): 469-477.]
[6] Ji Shaocheng, Mainprice D. Seismic anisotropy in the lower crust induced by the lattice preferred orientations of minerals [J]. Seismology and Geology, 1989, 11 (4): 15-23. [嵇少丞,Mainprice D. 晶格优选定向和下地壳地震波各向异性[J]. 地震地质, 1989, 11 (4): 15-23.] 
[7] Kern H, Wenk H-R. Fabric-related velocity anisotropy and shear wave splitting in rocks from the Santa Rosa mylonite zone, California [J]. Journal of Geophysical Research, 1990, 95: 11 213-11 223.
[8] Kern H, Burlini L, Ashchepkov V I. Fabric-related seismic anisotropy in upper mantle xenoliths: Evidence from measurements and calculations [J]. Physics of the Earth and Planetary Interiors, 1996, 95: 195-209.
[9] Christensen N I. Continental mantle seismic anisotropy: A new look at the Twin Sisters massif [J]. Tectonophysics, 2002, 355: 163-170.
[10] Tong C, Gudmundsson O, Kennett B L N. Shear wave splitting in refracted waves returned form the upper mantle transition zone beneath northern Australia [J]. Journal of Geophysical Research, 1994, 99: 15 783-15 797.
[11] Fouch M J, Fischer K M. Mantle anisotropy beneath southwest Pacific subduction zones [J]. Journal of Geophysical Research, 1996, 101: 15 987-16 002.
[12] Vinnik L P, Chevrot S, Montagner J P. Seismic evidence of flow at the base of the upper mantle [J]. Geophysical Research Letters, 1998, 25: 1 995-1 998.
[13] Vinnik L P, Romanowicz B, Le Stunff Y, et al. Seismic anisotropy in D"-layer [J]. Geophysical Research Letters, 1995, 22: 1 657-1 660.
[14] Lay T, Williams Q, Garnero E J. The core-mantle boundary layer and deep earth dynamics [J]. Nature, 1998, 392: 461-468.
[15] Ribe N M. On the relation between seismic anisotropy and finite strain [J]. Journal of Geophysical Research, 1992, 97: 8 737-8 747.
[16] Silver P G, Chan W W. Shear wave splitting and subcontinental mantle deformation [J]. Journal of Geophysical Research, 1991, 96: 16 429-16 454.
[17] Silver P G. Seismic anisotropy beneath the continents: Probing the depths of geology [J]. Annual Review of Earth and Planetary Sciences, 1996, 24: 385-432.
[18] Crampin S. Aligned cracks not LPO as the cause of mantle anisotropy[J]. Geophysical Research Abstracts, 2003, 5: 205.
[19] Plomerov J, Kouba D, Babu ka V. Mapping the lithosphere-asthenosphere boundary through changes in surface-wave anisotropy [J]. Tectonophysics, 2002, 158: 175-185.
[20] Tommasi A, Tikoff B, Vauchez A. Upper mantle tectonics: Three-dimensional deformation, olivine crystallographic fabrics and seismic properties [J]. Earth and Planetary Science Letters, 1999, 168: 173-186.
[21] Montagner J-P. Where can seismic anisotropy be detected in the Earth's mantle? In boundary layers [J]. Pure and Applied Geophysics, 1998, 151: 223-256.
[22] Montagner J-P, Guillot L. Seismic anisotropy and global geodynamics [A]. In: Karato S-I, Wenk H-R, eds. Plastic Deformation of Minerals and Rocks[C]. Washington DC: American Mineralogical Society, 2002. 353-380.
[23] Karato S-I. Seismic anisotropy in the deep mantle, boundary layers and the geometry of mantle convection [J]. Pure and Applied Geophysics, 1998, 151: 565-587.
[24] Jin Shuyan. Plagioclase fabrics and seismic anisotropy of the lower crust [J]. Geologcial Science and Technology Information, 2000, 19 (3): 1-6. [金淑燕. 斜长石组构与下地壳各向异性[J]. 地质科技情报, 2000, 19 (3): 1-6.] 
[25] Weiss T, Siegesmund S, Rabbel W, et al. Seismic velocities and anisotropy of the lower continental crust: A review [J]. Pure and Applied Geophysics, 1999, 156: 97-122.
[26] Jin Shuyan. Rock fabric and anisotropy of the upper mantle [J]. Geological Science and Technology Information, 1993, 12 (3): 32-38. [金淑燕. 上地幔岩石组构和各向异性[J]. 地质科技情报, 1993, 12 (3): 32-38.]
[27] Anderson D L. Theory of the Earth [M]. Guan Huaping, Yang Yurong, Liu Xiaowei, et al, translate. Beijing: Seismological Press, 1993. 403-440. [Anderson D L. 地球的理论[M].关华平, 杨玉荣, 刘小伟,等译.北京: 地震出版社,1993. 403-440.] 
[28] Gledhill K. Evidence for shallow and pervasive anisotropy in the Wellington region, New Zealand [J]. Journal of Geophysical Research, 1991, 96: 21 503-21 516.
[29] Gledhill K, Stuart G. Seismic anisotropy in the fore-arc region of the Hikurangi subduction zone, New Zealand [J]. Physics of the Earth and Planetary Interiors, 1996, 95: 211-225.
[30] Bowman J R, Ando M. Shear-wave splitting the upper-mantle wedge above the Tonga subduction zone [J]. Geophysical Journal of the Royal Astronomical Society, 1987, 88: 25-41.
[31] Ildaka T, Obara K. Shear-wave splitting anisotropy in the mantle wedge above the subduction Pacific plate [J]. Tectonophysics, 1995, 249: 53-68.
[32] Hiramatsu Y, Ando M. Seismic anisotropy near source region in subduction zones around Japan [J]. Physics of the Earth and Planetary Interiors, 1996, 95: 237-250.
[33] Gledhill K, Gubbins K. SKS splitting and the seismic anisotropy of the mantle beneath the Hikurangi subduction zone, New Zealand [J]. Physics of the Earth and Planetary Interiors, 1996, 95: 227-236.
[34] Farra V, Vinnik L. Shear-wave splitting in the mantle of the Pacific [J]. Geophysical Journal International, 1994, 119: 195-218.
[35] Russo R, Silver P. Trench parallel flow beneath the Nazca plate from seismic anisotropy [J]. Science, 1994, 263: 1 105-1 111.
[36] Kaneshima S, Silver P G. Seismic anisotropy in the mantle beneath Central Peru [J]. Physics of the Earth and Planetary Interiors, 1995, 88: 257-272.
[37] Fischer K M, Yang X. Anisotropy in Kuril-Kamtchatka subduction zone structure [J]. Geophysical Research Letters, 1994, 21: 5-8.
[38] Buttles J, Olson P. A laboratory model of subduction zone anisotropy [J]. Earth and Planetary Science Letters, 1998, 164: 245-262.
[39] Yang X, Fischer K M, Abers G A. Seismic anisotropy beneath the Shumagin Islands segment of the Aleutian Alaska subduction zone [J]. Journal of Geophysical Research, 1995, 100: 18 165-18 177.
[40] Fischer K M, Wiens D A. The depth distribution of mantle anisotropy beneath the Tonga subduction zone [J]. Earth and Planetary Science Letters, 1996, 142: 253-260.
[41] Vauchez A, Tommasi A, Barruol G, et al. Upper mantle deformation and seismic anisotropy in continental rifts [J]. Physics and Chemistry of Earth, 2000, 25(2): 111-117.
[42] Gao S, Davis P M, Liu H, et al. Seismic anisotropy and mantle flow beneath the Baikal rift zone [J]. Nature, 1994, 371: 149-151.
[43] Sandvol E, Ni J, Ozalaybey S. Shear-wave splitting in the Rio Grande rift [J]. Geophysical research Letters, 1992, 19: 2 337-2 340.
[44] Gao S, Davis P M, Liu H, et al. SKS splitting beneath continental rift zones [J]. Journal of Geophysical Research, 1997, 102: 22 781-22 797.
[45] Vauchez A, Barruol G, Nicolas A. Comment on "SKS splitting beneath continental rift zones" by Gao et al [J]. Journal of Geophysical Research, 1999, 104: 10 787-10 789.
[46] Wookey J, Kendall J-M, Barruol G. Mid-mantle deformation inferred from seismic anisotropy [J]. Nature, 2002, 415: 777-780.
[47] Trampert J, van Heust H J. Global azimuthal anisotropy in the transition zone [J]. Science, 2002, 296: 1 297-1 299.
[48] Mainprice D, Silver P G. Interpretation of SKS-waves using samples from the subcontinental lithosphere [J]. Physics of the Earth and Planetary Interiors, 1993, 78: 257-280.
[49] Makeyeva L I, Vinnik L P, Roecker S W. Shear-wave splitting and small-scale convection in the continental upper mantle [J]. Nature, 1992, 358: 144-147.
[50] Mcnamara D E, Owens T J, Silver P G, et al. Shear wave anisotropy beneath the Tibetan Plateau [J]. Journal of Geophysical Research, 1994, 99: 13 655-13 665.
[51] Hirn A, Jiang M, Sapin M, et al. Seismic anisotropy as an indicator of mantle flow beneath the Himalayas and Tibet [J]. Nature,1995, 375: 571-574.
[52] Herquel G, Wittlinger G, Guilbert J. Anisotropy and crustal thickness of Northern-Tibet: New constraints for tectonic modeling [J]. Geophysical Research Letters, 1995, 22: 1 925-1 928.
[53] Lav J, Avouac J P, Lacassin R, et al. Seismic anisotropy beneath Tibet: Evidence for eastward extrusion of the Tibetan lithosphere?[J]. Earth and Planetary Science Letters, 1996, 140: 83-96.
[54] Guilbert J, Poupinet G, Jiang M. A study of azimuthal P residuals and shear wave splitting across the Kunlun range (Northern Tibetan Plateau) [J]. Physics of the Earth and Planetary Interiors, 1996, 95: 167-174.
[55] Lü Qingtian, Ma Kaiyi, Jiang Mei, et al. Seismic anisotropy of transverses waves beneath Southern Tibet [J]. Acta Seismologica Sinica, 1996, 18 (2): 215-223. [吕庆田, 马开义, 姜枚, 等. 青藏高原南部下的横波各向异性[J]. 地震学报, 1996, 18 (2): 215-223. ] 
[56] Shi Danian, Dong Yingjun, Jiang Mei, et al. Shear wave anisotropy of the upper mantle beneath the Tingri of Tibet to Golmud of Qinghai [J].Acta Geologica Sinica, 1996, 70 (4): 291-297. [史大年, 董英君, 姜枚, 等. 西藏定日—青海格尔木上地幔各向异性研究[J]. 地质学报, 1996, 70 (4): 291-297.]
[57] Sandvol E, Ni J F, Kind R, et al. Seismic anisotropy beneath the southern Himalayas-Tibet collision zone [J]. Journal of Geophysical Research, 1997, 102: 17 813-17 823.
[58] Davis P, England P, Houseman G. Comparison of shear wave splitting and finite strain from the India-Asia collision zone [J]. Journal of Geophysical Research, 1997, 102: 27 511-27 522.
[59] Chen W-P, Ozalaybey S. Correlation between seismic anisotropy and Bouguer gravity anomalies in Tibet and its implications for lithospheric structures [J]. Geophysical Journal International,1998, 135: 93-101.
[60] Huang W-C, Ni J F, Tilmann F, et al. Seismic polarization anisotropy beneath the central Tibetan Plateau [J]. Journal of Geophysical Research, 2000, 105: 27 979-27 989.
[61] Jiang Mei, Xu Zhiqin, Hirn A, et al. Teleseimic anisotropy and corresponding features of the upper mantle in Tibet plateau and its neighboring areas [J]. Acta Geoscientia Sinica,2001, 22(2): 111-116. [姜枚, 许志琴, Hirn A, 等.青藏高原及其部分邻区地震各向异性和上地幔特征[J].地球学报, 2001, 22(2): 111-116.] 
[62] Meissner R, Mooney W D, Artemieva I. Seismic anisotropy and mantle creep in young orogens [J]. Geophysical Journal International, 2002, 149: 1-14.
[63] Holt W. Correlated crust and mantle strain fields in Tibet[J]. Geology, 2000, 28: 67-70.
[64] Yang Xiaosong, Jin Zhenmin, Ma Jin, et al. Genesis of SKS splitting in the North-central Qinghai-Xizang plateau: Melt alignment enhanced lithosphere anisotropy [J]. Acta Geophysica Sinica,2002, 45 (6): 821-831. [杨晓松, 金振民, 马瑾, 等. 地球物理学报, 2002, 45 (6): 821-831.] 
[65] Matte P, Mattauer M, Olivet J M. Continental subductions beneath Tibet and the Himalayan orogeny: A review[J].Terra Nova,1997, 9: 264-270.
[66] Jin Zhenmin, Jin Shuyan, Li Juanbo. The relationship between petrofabric and seismic wave anisotropy of deformed rocks—A bridge between geodynamics and seismology [J]. Advances in Earth Science, 1990,(5): 39-42. [金振民,金淑燕,李隽波. 地球动力学和地震学的桥梁——变形岩石组构与波速各向异性关系[J]. 地球科学进展, 1990,(5):39-42.] 
[67] Silver P G, Chan W W. Implications for continental structure and evolution from seismic anisotropy [J]. Nature, 1988, 335: 34-39.
[68] Schulte-Pelkum V, Blackman D K. A synthesis of seismic P and S anisotropy [J]. Geophysical Journal International, 2003, 154: 166-178.
[69] Park J, Levin V. Seismic anisotropy: Tracing plate dynamics in the mantle [J]. Science, 2002, 296: 485-489.
[70] Montagner J-P, Pommera D-A, Lav J. How to relate body wave and surface wave anisotropy?[J].Journal of Geophysical Research, 2000, 105: 19 015-19 027.
[71] Christensen N I, Medaris L G, Wang H F. Depth variation of seismic anisotropy and petrology in central European lithosphere: A tectonothermal synthesis from spinel lherzolite [J]. Journal of Geophysical Research, 2001, 106:645-664.
[72] Jung H, Karato S-I. Water-induced fabric transitions in olivine [J]. Science, 2001, 293: 1 460-1 463.
[73] Smith G P, Wiens D A, Fischer K M, et al. A complex pattern of mantle flow in the Lau backarc [J].Science, 2001, 292: 713-716.
[74] Stretton I, Heidelbach F, Mackwell S, et al. Dislocation creep of magnesiow stite (Mg_0.8Fe_0.2O) [J].Earth and Planetary Science Letters, 2001, 194: 229-240.
[75] Teng Jiwen, Zhang Zhongjie, Wang Guangjie, et al. The seismic anisotropy and geodynamics of Earth’s interior media [J]. Progress in Geophysics, 2000, 15 (1): 1-35. [滕吉文, 张中杰, 王光杰, 等.地球内部各圈层介质的地震各向异性与地球动力学[J].地球物理学进展, 2000, 15 (1): 1-35.] 
[76] Zhang Z, Li Y, Lu D, et al. Velocity and anisotropy structure of the crust in the Dabieshan orogenic belt from wide-angle seismic data [J]. Physics of the Earth and Planetary Interiors, 2000, 122: 115-131.

[1]	兰爱玉, 林战举, 范星文, 姚苗苗. 青藏高原北麓河多年冻土区阴阳坡地表能量和浅层土壤温湿度差异研究[J]. 地球科学进展, 2021, 36(9): 962-979.
[2]	仲雷,葛楠,马耀明,傅云飞,马伟强,韩存博,王显,程美琳. 利用静止卫星估算青藏高原全域地表潜热通量[J]. 地球科学进展, 2021, 36(8): 773-784.
[3]	王慧,张璐,石兴东,李栋梁. 2000年后青藏高原区域气候的一些新变化[J]. 地球科学进展, 2021, 36(8): 785-796.
[4]	田凤云,吴成来,张贺,林朝晖. 基于 CAS-ESM2的青藏高原蒸散发的模拟与预估[J]. 地球科学进展, 2021, 36(8): 797-809.
[5]	马宁. 近 40年来青藏高原典型高寒草原和湿地蒸散发变化的对比分析[J]. 地球科学进展, 2021, 36(8): 836-848.
[6]	柯思茵,张冬丽,王伟涛,王孟豪,段磊,杨敬钧,孙鑫,郑文俊. 青藏高原东北缘晚更新世以来环境变化研究进展[J]. 地球科学进展, 2021, 36(7): 727-739.
[7]	魏梦美,符素华,刘宝元. 青藏高原水力侵蚀定量研究进展[J]. 地球科学进展, 2021, 36(7): 740-752.
[8]	李耀辉, 孟宪红, 张宏升, 李忆平, 王闪闪, 沙莎, 莫绍青. 青藏高原—沙漠的陆—气耦合及对干旱影响的进展及其关键科学问题[J]. 地球科学进展, 2021, 36(3): 265-275.
[9]	张晓智, 周怀阳, 钱生平. 俯冲带岩浆弧安山岩的成因研究进展[J]. 地球科学进展, 2021, 36(3): 288-306.
[10]	杨军怀,夏敦胜,高福元,王树源,陈梓炫,贾佳,杨胜利,凌智永. 雅鲁藏布江流域风成沉积研究进展[J]. 地球科学进展, 2020, 35(8): 863-877.
[11]	姚天次,卢宏玮,于庆,冯玮. 近 50年来青藏高原及其周边地区潜在蒸散发变化特征及其突变检验[J]. 地球科学进展, 2020, 35(5): 534-546.
[12]	张宏文,续昱,高艳红. 1982— 2005年青藏高原降水再循环率的模拟研究[J]. 地球科学进展, 2020, 35(3): 297-307.
[13]	苗毅, 刘海猛, 宋金平, 戴特奇. 青藏高原交通设施建设及影响评价研究进展[J]. 地球科学进展, 2020, 35(3): 308-318.
[14]	牛富俊, 王玮, 林战举, 罗京. 青藏高原多年冻土区热喀斯特湖环境及水文学效应研究[J]. 地球科学进展, 2018, 33(4): 335-342.
[15]	刘懿馨, 侯克选, 沙鑫, 马蓁, 王金荣. 北祁连西段熬油沟组玄武岩地球化学特征及构造意义[J]. 地球科学进展, 2018, 33(2): 189-205.

阅读次数

全文

摘要

SEISMIC ANISOTROPY: A PROBE TO UNDERSTAND THE STRUCTURE IN EARTH’S INTERIOR 