CUI Qing-Hui,
GAO Ya-Jian,
ZHOU Yuan-Ze
.2017.The nature of the lithosphere-asthenosphere boundary beneath the central South America area from the stacking of sP precursors.Chinese Journal Of Geophysics,60(7): 2589-2598,doi: 10.6038/cjg20170708
The nature of the lithosphere-asthenosphere boundary beneath the central South America area from the stacking of sP precursors
CUI Qing-Hui1,2, GAO Ya-Jian1,2, ZHOU Yuan-Ze1,2
1. College of Earth Science, University of Chinese Academy of Sciences, Beijing 100049, China; 2. Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, Beijing 100049, China
Abstract：The lithosphere-asthenosphere boundary (LAB) is the seismic discontinuity with a negative velocity contrast in the upper mantle. Seismic detections on the LAB in subduction zone region are helpful to understand the interaction between the lithosphere and asthenosphere and the geodynamic process associated with the slab subduction. In this paper, the vertical broadband waveforms are collected from four deep earthquakes occurred from 2006 to 2012 beneath the central South America area. The waveform data is processed with the linear slant stack method to get the vespagrams in the relative travel-time to slowness domain, and the sP precursors reflected from the bottom of the LAB (sLABP) are successfully extracted. Based on the one-dimensional modified velocity model (IASP91-SA), we obtain the horizontal distributions for the six sLABP reflected points, which are divided into the western part (Ⅰ) and the eastern part (Ⅱ). In part I, the LAB depths range between 60 and 63 km, with the average depth of 61 km and the topography of 3 km; in part Ⅱ, the LAB depths range between 78 and 82 km, with the average depth of 80 km and the topography of 4 km. Our results reveal the increasing LAB depths from west to east in the central South America area, and the trend may possibly represent the reformation differences to the continental lithosphere. We infer that the continental lithosphere may be subjected to the stronger erosion in the area near the trench, for the higher degree of partial melting and the more fertile melts in the asthenosphere; the continental lithosphere may be subjected to the weaker erosion in the area far from the trench, for the lower degree of partial melting and the less fertile melts in the asthenosphere.
Amante C, Eakins B W. 2009. ETOPO1:1 arc-minute global relief model:procedures, data sources and analysis. NOAA Technical Memorandum NESDIS NGDC-24. National Geophysical Data Center, NOAA, doi:10.7289/V5C8276M. Artemieva I M. 2011. The Lithosphere, An Interdisciplinary Approach. New York:Cambridge University Press. Buland R, Chapman C H. 1983. The computation of seismic travel times. Bull. Seismol. Soc. Am., 73(5):1271-1302. Cahill T, Isacks B L. 1992. Seismicity and shape of the subducted Nazca Plate. J. Geophys. Res., 97(B12):17503-17529, doi:10.1029/92jb00493. Chen J, Zhou Y Z, Wang H C. 2014. Detection of the Lehmann discontinuity beneath Tonga with short-period waveform data from Hi-net. Science China Earth Sciences, 57(8):1953-1960, doi:10.1007/s11430-014-4834-3. Collier J D, Helffrich G R. 1997. Topography of the "410" and "660" km seismic discontinuities in the Izu-Bonin subduction zone. Geophys. Res. Lett., 24(12):1535-1538, doi:10.1029/97gl01383. Collier J D, Helffrich G R. 2001. The thermal influence of the subducting slab beneath South America from 410 and 660 km discontinuity observations. Geophys. J. Int., 147(2):319-329, doi:10.1046/j.1365-246X.2001.00532.x. Collier J D, Helffrich G R, Wood B J. 2001. Seismic discontinuities and subduction zones. Phys. Earth Planet. Inter., 127(1-4):35-49, doi:10.1016/S0031-9201(01)00220-5. Contenti S, Gu Y J, Ökeler A, et al. 2012. Shear wave reflectivity imaging of the Nazca-South America subduction zone:stagnant slab in the mantle transition zone?. Geophys. Res. Lett., 39(2):L02310, doi:10.1029/2011gl050064. Crotwell H P, Owens T J, Ritsema J. 1999. The TauP toolkit:flexible seismic travel-time and ray-path utilities. Seismol. Res. Lett., 70(2):154-160, doi:10.1785/gssrl.70.2.154. Cui H H, Gao Y J, Zhou Y Z. 2017. Seismic evidence of the lithosphere-asthenosphere boundary beneath Izu-Bonin area. Chin. Sci. Bull. (in Chinese), 62(7):711-720, doi:10.1360/N972016-00889. Cui H H, Zhou Y Z, Chen Y L. 2017. Seismic evidence of the lithosphere-asthenosphere boundary beneath the Tonga area, southwestern Pacific. J. Asian Earth Sci., 138:129-135, doi:10.1016/j.jseaes.2017.02.013. Dziewonski A M, Chou T A, Woodhouse J H. 1981. Determination of earthquake source parameters from waveform data for studies of global and regional seismicity. J. Geophys. Res., 86(B4):2825-2852, doi:10.1029/JB086iB04p02825. Eaton D W, Darbyshire F, Evans R L, et al. 2009. The elusive lithosphere-asthenosphere boundary (LAB) beneath cratons. Lithos, 109(1-2):1-22, doi:10.1016/j.lithos.2008.05.009. Ekström G, Nettles M, Dziewoński A M. 2012. The global CMT project 2004-2010:centroid-moment tensors for 13, 017 earthquakes. Phys. Earth Planet. Inter., 200-201:1-9, doi:10.1016/j.pepi.2012.04.002. Fischer K M, Ford H A, Abt D L, et al. 2010. The lithosphere-asthenosphere boundary. Annu. Rev. Earth Planet. Sci., 38(1):551-575, doi:10.1146/annurev-earth-040809-152438. Flanagan M P, Shearer P M. 1998. Topography on the 410 km seismic velocity discontinuity near subduction zones from stacking of sS, sP, and pP precursors. J. Geophys. Res., 103(B9):21165-21182, doi:10.1029/98jb00595. Fukao Y, Obayashi M. 2013. Subducted slabs stagnant above, penetrating through, and trapped below the 660 km discontinuity. J. Geophys. Res., 118(11):5920-5938, doi:10.1002/2013JB010466. Gudmundsson ó, Sambridge M. 1998. A regionalized upper mantle (RUM) seismic model. J. Geophys. Res., 103(B4):7121-7136, doi:10.1029/97jb02488. Gutenberg B. 1959. Physics of the Earth's Interior. New York:Academic Press. He L J. 2014. Numerical modeling of convective erosion and peridotite-melt interaction in big mantle wedge:implications for the destruction of the North China Craton. J. Geophys. Res., 2013, 119(4):3662-3677, doi:10.1002/2013jb010657. Heit B, Sodoudi F, Yuan X H, et al. 2007. An S receiver function analysis of the lithospheric structure in South America. Geophys. Res. Lett., 34(14):L14307, doi:10.1029/2007gl030317. Helffrich G. 2000. Topography of the transition zone seismic discontinuities. Rev. Geophys., 38(1):141-158, doi:10.1029/1999RG000060. Huang J L, Zhao D P. 2006. High-resolution mantle tomography of China and surrounding regions. J. Geophys. Res., 111(B9):B09305, doi:10.1029/2005JB004066. Jiang Z Y, Zang S X, Zhou Y Z. 2002. Topographies of seismic velocity discontinuities and penetrations of subducting slabs beneath the Sea of Okhotsk. Chin. Sci. Bull., 47(24):2034-2041. Kaneshima S. 2016. Seismic scatterers in the mid-lower mantle. Phys. Earth Planet. Inter., 257:105-114, doi:10.1016/j.pepi.2016.05.004. Karato S I. 2012. On the origin of the asthenosphere. Earth Planet. Sci. Lett., 321-322:95-103, doi:10.1016/j.epsl.2012.01.001. Karato S I, Jung H. 1998. Water, partial melting and the origin of the seismic low velocity and high attenuation zone in the upper mantle. Earth Planet. Sci. Lett., 157(3-4):193-207, doi:10.1016/S0012-821X(98)00034-X. Kawamoto T, Yoshikawa M, Kumagai Y, et al. 2013. Mantle wedge infiltrated with saline fluids from dehydration and decarbonation of subducting slab. Proc. Natl. Acad. Sci. USA, 110(24):9663-9668, doi:10.1073/pnas.1302040110. Kendrick E, Bevis M, Smalley R Jr, et al. 2003. The Nazca-South America Euler vector and its rate of change. J. South Am. Earth Sci., 16(2):125-131, doi:10.1016/S0895-9811(03)00028-2. Kennett B L N, Engdahl E R. 1991. Traveltimes for global earthquake location and phase identification. Geophys. J. Int., 105(2):429-465, doi:10.1111/j.1365-246X.1991.tb06724.x. Laske G, Masters G, Ma Z, et al. 2012. CRUST1.0:An updated global model of Earth's crust. EGU General Assembly, 14:3743, http://igppweb.ucsd.edu/~gabi/crust1.html. Li C, Van Der Hilst R D, Engdahl E R, et al. 2008a. A new global model for P wave speed variations in Earth's mantle. Geochem. Geophys. Geosyst., 9(5):Q05018, doi:10.1029/2007GC001806. Li J, Chen Q F, Vanacore E, et al. 2008b. Topography of the 660 km discontinuity beneath northeast China:implications for a retrograde motion of the subducting Pacific slab. Geophys. Res. Lett., 35(1):L01302, doi:10.1029/2007GL031658. McFadden P L, Drummond B J, Kravis S. 1986. The Nth-root stack:theory, applications, and examples. Geophysics, 51(10):1879-1892, doi:10.1190/1.1442045. Niu F L, Kawakatsu H, Fukao Y. 2003. Seismic evidence for a chemical heterogeneity in the midmantle:a strong and slightly dipping seismic reflector beneath the Mariana subduction zone. J. Geophys. Res., 108(B9):2419, doi:10.1029/2002jb002384. Obayashi M, Yoshimitsu J, Nolet G, et al. 2013. Finite frequency whole mantle P wave tomography:improvement of subducted slab images. Geophys. Res. Lett., 40(21):5652-5657, doi:10.1002/2013gl057401. Ohtani E. 2005. Water in the mantle. Elements., 1(1):25-30, doi:10.2113/gselements.1.1.25. Ohtani E, Zhao D. 2009. The role of water in the deep upper mantle and transition zone:dehydration of stagnant slabs and its effects on the big mantle wedge. Russ. Geol. Geophys., 50(12):1073-1078, doi:10.1016/j.rgg.2009.11.006. Pardo-Casas F, Molnar P. 1987. Relative motion of the Nazca (Farallon) and South American plates since late Cretaceous time. Tectonics, 6(3):233-248, doi:10.1029/TC006i003p00233. Pasyanos M E, Masters T G, Laske G, et al. 2014. LITHO1.0:an updated crust and lithospheric model of the Earth. J. Geophys. Res., 119(3):2153-2173, doi:10.1002/2013JB010626. Phillips K, Clayton R W. 2014. Structure of the subduction transition region from seismic array data in southern Peru. Geophys. J. Int., 196(3):1889-1905, doi:10.1093/gji/ggt504. Phillips K, Clayton R W, Davis P, et al. 2012. Structure of the subduction system in southern Peru from seismic array data. J. Geophys. Res., 117(B11):B11306, doi:10.1029/2012jb009540. Qin M Z, Zhang Y S, Liu X Z, et al. 2016. On "410" discontinuity depth of the Tonga-Fiji subduction zone by the sP precursor recorded by Gansu seismic network. Acta Seismologica Sinica (in Chinese), 38(1):53-58, doi:10.11939/jass.2016.01.005. Rawlinson N, Sambridge M. 2004. Wave front evolution in strongly heterogeneous layered media using the fast marching method. Geophys. J. Int., 156(3):631-647, doi:10.1111/j.1365-246X.2004.02153.x. Ritsema J, Deuss A, Van Heijst H J, et al. 2011. S40RTS:a degree-40 shear-velocity model for the mantle from new Rayleigh wave dispersion, teleseismic traveltime and normal-mode splitting function measurements. Geophys. J. Int., 184(3):1223-1236, doi:10.1111/j.1365-246X.2010.04884.x. Ritsema J, Van Heijst H J, Woodhouse J H. 2004. Global transition zone tomography. J. Geophys. Res., 109(B2):B02302, doi:10.1029/2003jb002610. Romanowicz B. 2009. The thickness of tectonic plates. Science, 324(5926):474-476, doi:10.1126/science.1172879. Rost S, Thomas C. 2002. Array seismology:mehods and applications. Rev. Geophys., 40(3):2-1-2-27, doi:10.1029/2000rg000100. Rost S, Thomas C. 2009. Improving seismic resolution through array processing techniques. Surv. Geophys., 30(4):271-299, doi:10.1007/s10712-009-9070-6. Schmerr N, Garnero E J. 2007. Upper mantle discontinuity topography from thermal and chemical heterogeneity. Science, 318(5850):623-626, doi:10.1126/science.1145962. Stern R J. 2002. Subduction zones. Rev. Geophys., 40(4):3-1-3-38, doi:10.1029/2001RG000108. Sui Y, Zhou Y Z, Wang X R. 2015. The effects of stagnant slabs on the topography of 410 km discontinuity beneath the Pamir-Hindu Kush. Chinese J. Geophys.(in Chinese), 58(1):125-133, doi:10.6038/cig20150110. Uyeda S, Kanamori H. 1979. Back-arc opening and the mode of subduction. J. Geophys. Res., 84(B3):1049-1061, doi:10.1029/JB084iB03p01049. Vinnik L, Niu F L, Kawakatsu H. 1998. Broadband converted phases from midmantle discontinuities. Earth, Planets and Space, 50(11-12):987-997, doi:10.1186/bf03352193. Wang X R, Li G H, Cui H H, et al. 2015. Constraining the discontinuity structure of the upper mantle beneath the Tonga-Fiji subduction zone based on secondary phases. Progress in Geophysics (in Chinese), 30(5):2089-2099, doi:10.6038/pg20150512. Wei R Q, Li W Y. 2015. Thermal-rheological bottom boundary of continental lithosphere:case studies on cratons of Kaapvaal, Fennoscandia, and Slave. J. Univ. Chin. Acad. Sci. (in Chinese), 32(1):74-81. Wessel P, Smith W H F. 1998. New, improved version of generic mapping tools released. EOS, Trans. Amer. Geophys. Union., 79(47):579, doi:10.1029/98EO00426. Xie C X, Zhou Y Z, Wang Z J, et al. 2012. Evidence of SdP conversion phases for the 300 km discontinuity beneath Tonga-Fiji region. Chinese J. Geophys.(in Chinese), 55(5):1591-1600, doi:10.6038/j.issn.0001-5733.2012.05.017. Yang Z T, He X B. 2015. Oceanic crust in the mid-mantle beneath west-central Pacific subduction zones:evidence from S-to-P converted waveforms. Geophys. J. Int., 203(1):541-547, doi:10.1093/gji/ggv314. Yuan X H, Sobolev S V, Kind R, et al. 2000. Subduction and collision processes in the central Andes constrained by converted seismic phases. Nature, 408(6815):958-961, doi:10.1038/35050073. Zang S X, Zhou Y Z. 2002. The method of N-th root slant stack and its application in study of mantle discontinuities. Chinese J. Geophys. (in Chinese), 45(3):420-429, doi:10.3321/j.issn:0001-5733.2002.03.012. Zang S X, Zhou Y Z, Jiang Z Y. 2003. Mantle discontinuities beneath Izu-Bonin and the implications. Science in China Series D:Earth Sciences (in Chinese), 46(12):1201-1211. Zang S X, Zhou Y Z, Ning J Y, et al. 2006. Multiple discontinuities near 660 km beneath Tonga area. Geophys. Res. Lett., 33(20):L20312, doi:10.1029/2006GL027262. Zheng Y F, Chen Y X, Dai L Q, et al. 2015. Developing plate tectonics theory from oceanic subduction zones to collisional orogens. Science China Earth Sciences (in Chinese), 58(7):1045-1069, doi:10.1007/s11430-015-5097-3. Zheng Y C, Lay T, Flanagan M P, et al. 2007. Pervasive seismic wave reflectivity and metasomatism of the Tonga mantle wedge. Science, 316(5826):855-859, doi:10.1126/science.1138074. Zhou Y Z, Sui Y. 2010. On the velocity interfaces in the lower mantle beneath South America. Chinese J. Geophys. (in Chinese), 53(1):86-93, doi:10.3969/j.issn.0001-5733.2010.01.009. Zhou Y Z, Wang Z J. 2011. On the difference of mid-mantle multiple velocity structure beneath Izu-Bonin and Tonga areas. Science China Earth Science (in Chinese), 41(7):936-944. Zhou Y Z, Yu X W, Yang H, et al. 2012. Multiplicity of the 660-km discontinuity beneath the Izu-Bonin area. Phys. Earth Planet. Inter., 198-199:51-60, doi:10.1016/j.pepi.2012.03.003. Zhou Y Z, Zang S X. 2001. Mantle discontinuities beneath the stations MDJ and HIA and its implications. Chinese J. Geophys.(in Chinese), 44(6):761-773, doi:10.3321/j.issn:0001-5733.2001.06.005. 崔辉辉, 高雅健, 周元泽. 2017. 伊豆-小笠原地区岩石圈软流圈边界地震学证据. 科学通报, 62(7):711-720, doi:10.1360/N972016-00889. 蒋志勇, 臧绍先, 周元泽. 2003. 鄂霍次克海下间断面的起伏及俯冲带的穿透. 科学通报, 48(4):320-327. 秦满忠, 张元生, 刘旭宙等. 2016. 利用甘肃地震台网记录的sP前驱波研究汤加-斐济俯冲区"410"间断面深度. 地震学报, 38(1):53-58, doi:10.11939/jass.2016.01.005. 眭怡, 周元泽, 王晓冉. 2015. 帕米尔-兴都库什深俯冲残留体对410 km间断面起伏形态的影响. 地球物理学报, 58(1):125-133, doi:10.6038/cig20150110. 王晓冉, 李国辉, 崔辉辉等. 2015. 基于次生震相的汤加-斐济地区上地幔间断面结构研究. 地球物理学进展, 30(5):2089-2099, doi:10.6038/pg20150512. 魏荣强, 李午阳. 2015. 大陆岩石圈的热-流变底边界——以Kaapvaal、Fennoscandia和Slave克拉通为例. 中国科学院大学学报, 32(1):74-81. 谢彩霞, 周元泽, 王卓君等. 2012. 汤加-斐济地区300 km间断面的SdP转换波证据. 地球物理学报, 55(5), doi:10.6038/j.issn.0001-5733.2012.05.017. 臧绍先, 周元泽. 2002. N次根倾斜叠加方法在间断面研究中的应用. 地球物理学报, 45(3):407-415, doi:10.3321/j.issn:0001-5733.2002.03.012. 臧绍先, 周元泽, 蒋志勇. 2003. 伊豆-小笠原地区地幔间断面的起伏及其意义. 中国科学:D辑, 33(3):193-201. 郑永飞, 陈伊翔, 戴立群等. 2015. 发展板块构造理论:从洋壳俯冲带到碰撞造山带. 中国科学:地球科学, 45(6):711-735, doi:10.1007/s11430-015-5097-3. 周元泽, 眭怡. 2010. 南美地区下地幔速度界面结构研究. 地球物理学报, 53(1):86-93, doi:10.3969/j.issn.0001-5733.2010.01.009. 周元泽, 王卓君. 2011. 伊豆-小笠原和汤加地区中地幔多层速度结构差异性研究. 中国科学:地球科学, 41(7):936-944. 周元泽, 臧绍先. 2001. 牡丹江和海拉尔台下方地幔间断面结构及推论. 地球物理学报, 44(6):761-773, doi:10.3321/j.issn:0001-5733.2001.06.005.
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