Crustal structure along the Zhenkang-Luxi deep seismic sounding profile in Yunnan derived from receiver functions
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摘要
The crustal thicknesses and the Poisson's ratios under the seismic stations can be calculated by receiver function method with H-κ stacking effectively. But the stacking results are affected to some extent by the average crustal P-wave velocity. To eliminate this effect and get more accurate crustal structure along the Zhenkang-Luxi deep seismic sounding profile which lies in Yunnan Province, we calculate the receiver functions from the teleseismic events recorded by 11 temporary stations as well as 5 permanent ones along the profile and carry out the stacking with Vp obtained from the profile in this study. Our study shows that the crustal thicknesses along the Zhenkang-Luxi profile range from 34.8 km to 41.8 km with an average of 39 km. The crust is thicker in the middle part of the profile and thinner in both sides in general. Dramatic changes of crustal thickness about 3 km are detected across both the Lancangjiang fault and the Xiaojiang fault, which implies that these faults cut through the Moho. The lowest Poisson's ratio under the stations is 0.22 and the highest is 0.27 with the mean of 0.25, which is lower than the global average value 0.27 in the continental crust. It suggests that most of the crust along the profile lacks mafic component, but contains more felsic substance. The low Poisson's ratio also indicates that there is no satisfying condition for partial melting. We deduce that the material flow in the middle-lower crust in the southeastern margin of the Tibetan plateau may occur only in the north region of 24°N.
The crustal thicknesses and the Poisson's ratios under the seismic stations can be calculated by receiver function method with H-κ stacking effectively. But the stacking results are affected to some extent by the average crustal P-wave velocity. To eliminate this effect and get more accurate crustal structure along the Zhenkang-Luxi deep seismic sounding profile which lies in Yunnan Province, we calculate the receiver functions from the teleseismic events recorded by 11 temporary stations as well as 5 permanent ones along the profile and carry out the stacking with Vp obtained from the profile in this study. Our study shows that the crustal thicknesses along the Zhenkang-Luxi profile range from 34.8 km to 41.8 km with an average of 39 km. The crust is thicker in the middle part of the profile and thinner in both sides in general. Dramatic changes of crustal thickness about 3 km are detected across both the Lancangjiang fault and the Xiaojiang fault, which implies that these faults cut through the Moho. The lowest Poisson's ratio under the stations is 0.22 and the highest is 0.27 with the mean of 0.25, which is lower than the global average value 0.27 in the continental crust. It suggests that most of the crust along the profile lacks mafic component, but contains more felsic substance. The low Poisson's ratio also indicates that there is no satisfying condition for partial melting. We deduce that the material flow in the middle-lower crust in the southeastern margin of the Tibetan plateau may occur only in the north region of 24°N.
The crustal thicknesses and the Poisson's ratios under the seismic stations can be calculated by receiver function method with H-κ stacking effectively. But the stacking results are affected to some extent by the average crustal P-wave velocity. To eliminate this effect and get more accurate crustal structure along the Zhenkang-Luxi deep seismic sounding profile which lies in Yunnan Province, we calculate the receiver functions from the teleseismic events recorded by 11 temporary stations as well as 5 permanent ones along the profile and carry out the stacking with Vp obtained from the profile in this study. Our study shows that the crustal thicknesses along the Zhenkang-Luxi profile range from 34.8 km to 41.8 km with an average of 39 km. The crust is thicker in the middle part of the profile and thinner in both sides in general. Dramatic changes of crustal thickness about 3 km are detected across both the Lancangjiang fault and the Xiaojiang fault, which implies that these faults cut through the Moho. The lowest Poisson's ratio under the stations is 0.22 and the highest is 0.27 with the mean of 0.25, which is lower than the global average value 0.27 in the continental crust. It suggests that most of the crust along the profile lacks mafic component, but contains more felsic substance. The low Poisson's ratio also indicates that there is no satisfying condition for partial melting. We deduce that the material flow in the middle-lower crust in the southeastern margin of the Tibetan plateau may occur only in the north region of 24°N.
引文
[1]P.Z.Zhang,Q.D.Deng,Z.Q.Zhang,H.B.Li,Active faults,earthquake hazards and associated geodynamic processes in continental China,Sci.China Earth Sci.43(10)(2013)1607-1620(in Chinese).
[2]C.Y.Wang,H.Lou,J.P.Wu,Z.M.Bai,F.G.Huang,J.Z.Qin,Seismological study on the crustal structure of Tengchong volcano-geothermal area,Acta Seismol.Sin.24(3)(2002)231-242(in Chinese).
[3]S.Z.Pan.F.Y.Wang,Y.H.Duan,X.G.Deng,X.H.Song,Y.L.Duan,Y.N.Sun,C.J.Zhang,Y.D.Yang,Y.R.Zang,Basement structure of southern Yunnan and adjacent areas:the Zhengkang-Luxi deep seismic sounding profile,Chinese J.Geophys.58(11)(2015)3917-3927(in Chinese).
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[6]M.K.Clark,L.H.Royden,Topographic ooze:building the eastern margin of Tibet by lower crustal flow,Geology 28(8)(2000)703-706.
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[8]P.Z.Zhang,Z.K.Shen,M.Wang,W.J.Gan,R.Burgmann,Z.J.Niu,J.Z.Sun,J.C.Wu,Continuous deformation of the Tibetan Plateau from global positioning system data,Geology 32(9)(2004)809-812.
[9]E.H.Zhang,H.Lou,S.X.Jia,Y.H.Li,The deep crust structure charcteristics beneath western Yunnan,Chinese J.Geophys.56(6)(2013)1915-1927(in Chinese).
[10]X.M.Xu,Z.F.Ding,F.X.Zhang,The teleseismic tomography study by P-wave traveltime data beneath the southern South-north Seismic Zone,Chinese J.Geophys.58(11)(2015)4041-4051(in Chinese).
[11]J.T.Pan,Y.H.Li,Q.J.Wu,Z.F.Ding,Phase velocity maps of Rayleigh waves in the southeast Tibetan Plateau,Chinese J.Geophys.58(11)(2015)3993-4006(in Chinese).
[12]M.Chen,H.Huang,H.J.Yao,R.Van der Hilst,F.L.Niu,Low wave speed zones in the crust beneath SE Tibet revealed by ambient noise adjoint tomography,Geophys.Res.Lett.41(2)(2014)334-340.
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[14]C.Y.Wang,L.P.Zhu,H.Lou,B.S.Huang,Z.X.Yao,X.H.Luo,Crustal thicknesses and Poisson's ratios in the eastern Tibetan Plateau and their tectonic implications,J.Geophys.Res.115(B11)(2010).https://doi.org/10.1029/2010JB007527.
[15]D.H.Bai,M.J.Unsworth,M.A.Meju,X.B.Ma,J.W.Teng,X.R.Kong,Y.Sun,J.Sun,L.F.Wang,C.S.Jiang,C.P.Zhao,P.F.Xiao,M.Liu,Crustal deformation of the eastern Tibetan Plateau revealed by magnetotelluric imaging,Nat.Geosci.3(5)(2010)358-362.
[16]R.Li,J.Tang,Z.Y.Dong,Q.B.Xiao,Y.Zhan,Deep electrical conductivity structure of the southern area in Yunnan Province,Chinese J.Geophys.57(4)(2014)1111-1122(in Chinese).
[17]W.C.Yang,Z.Z.Hou,C.Q,Yu,3D crustal density structure of West Yunnan and its tectonic implications,Chinese J.Geophys.58(11)(2015)3902-3916(in Chinese).
[18]L.Y.Lu,Z.Q.He,Z.F.Ding,C.Y.Wang,Azimuth anisotropy and velocity heterogeneity of Yunnan area based on seismic ambient noise,Chinese J.Geophys.57(3)(2014)822-836(in Chinese).
[19]L.P.Zhu,H.Kanamori,Moho depth variation in southern California from teleseismic receiver functions,J.Geophys.Res.105(B2)(2000)2969-2980.
[20]C.Q.Li,X.Z.Sheng,M.Z.Qin,The effect of P wave velocity on the H-k stacking results of receiver functions,Acta Seismol.Sin.36(3)(2014)480-490(in Chinese).
[21]X.F.Zheng,Z.X.Yao,J.S.Liang,J.Zheng,The role played and opportunities provided by IGP DMC of China National Seismic Network in Wenchuan earthquake disaster relief and researches,Bull.Seismol.Soc.Am.100(5B)(2010)2866-2872.
[22]Y.Z.Wang,E.N.Wang,Z.K.Shen,M.Wang,W.J.Gan,X.J.Qiao,G.J.Meng,T.M.Li,W.Tao,Y.L.Yang,J.Cheng,P.Li,GPS-constrained inversion of presentday slip rates along major faults of the Sichuan-Yunnan region,China Sci.China Earth Sci.38(5)(2008)582-597(in Chinese).
[23]L.P.Vinnik,Detection of waves converted from P to SV in the mantle,Phys.Earth Planet.Int.15(1)(1977)39-45.
[24]Q,J.Wu,R.S.Zeng,The crustal structure of Qinghai-Xizang Plateau inferred from broadband teleseismic waveform,Chinese J.Geophys.41(5)(1998)669-679(in Chinese).
[25]J.C.VanDecar,R.S.Crosson,Determination of teleseismic relative phase arrival times using multi-channle cross-correlation and least squares,Bull.Seismol.Soc.Am.80(1)(1990)150-169.
[26]J.P.Ligorrna,C.J.Ammon,Iterative deconvolution and receiver-function estimation,Bull.Seism.Soc.Am.89(5)(1999)1395-1400.
[27]X.H.Zha,J.S.Lei,Crustal thickness and Poisson's ratio beneath the Yunnan region,Sci.China Earth Sci.43(3)(2013)446-456.
[28]G.Zandt,C.J.Ammon,Continental crustal composition constrained by measurements of crustal Poisson's ratio,Nature 374(1994)152-154.
[29]C.Zhen,The structure of the crust and mantle beneath Southeast Tibetan Plateau from receiver function and surface wave dispersion,Institute of Geophysics,China Earthquake Administration,2016(in Chinese).
[30]F.Y.Wang,S.Z.Pan,L.Liu,B.F.Liu,J.S.Zhang,X.G.Deng,C.J.Ma,C.J.Zhang,Wide angle seismic exploration of Yuxi-Lincang profile-the research of crustal structure of the red river fault zone and southern Yunnan,Chinese J.Geophys.57(10)(2014)3247-3258(in Chinese).
[31]Z.J.Zhang,Z.M.Bai,C.Y.Wang,Q.T.Lv,J.W.Teng,J.L.Li,S.X.Sun,X.Z.Wang,Crustal structure of Gondwana and Yangtze-typed blocks:an example by wide angle seismic profile from Menglian to Malong in the western Yunnan,Sci.China Earth Sci.34(5)(2005)387-392(in Chinese).
[32]S.W.Chen,B.S.Wang,X.F.Tian,F.Y.Wang,B.F.Liu,L.Li,Crustal structure from Yunxian-Ninglang wide-angle seismic reflection and refraction profile in northwestern Yunnan,China Seismol.Geol.38(1)(2016)91-106(in Chinese).
[33]Z.J.Zhang,Z.M.Bai,C.Y.Wang.J.W.Teng,Q.T.Lv,J.L.Li,Y.F.Liu,Z.K.Liu,The crustal structure under Sanjiang and its dynamic implications:revealed by seismic reflection/refraction profile between Zhefang and Binchuan,Yunnan,Sci.China Earth Sci.35(4)(2005)314-319(in Chinese).
[34]C.Y.Wang,H.Lou,X.L.Wang,J.Z.Qin,R.H.Yang,J.M.Zhao,Crustal structure in Xiaojiang fault zone and its vicinity,Earthq.Sci.22(2009)347-356.
[35]T.Xu,Z.J.Zhang,B.F.Liu,Y.Chen,M.H.Zhang,X.B.Tian,Y.G.Xu,J.W.Teng,Crustal velocity structure in the Emeishan large igneous province and evidence of the Permian mantle plume activity,Sci.China Earth Sci.45(5)(2015)561-576(in Chinese).
[36]Z.M.Bai,Deep Seismic Sounding Tomography:Research and Application,Institute of Geophysics,China Earthquake Administration,2016(in Chinese).
[37]N.I.Christensen,Poisson's ratio and crustal seismology,J.Geophys.Res.101(B2)(1996)3139-3156.https://doi.org/10.1029/95JB03446.
[38]Y.G.Gao,Y.H.Li,Crustal thickness and Vp/Vs in the Northeast China-North China region and its geological implication,Chinese J.Geophys.57(3)(2014)847-857(in Chinese).
[39]C.Y.Wang,H.Lou,Z.X.Yao,X.H.Luo,Z.Y.Lv,Crustal thicknesses and possion's ratios in Longmenshan Mountains and adjacent regions,Quat.Sci.30(4)(2010)652-661(in Chinese).
[2]C.Y.Wang,H.Lou,J.P.Wu,Z.M.Bai,F.G.Huang,J.Z.Qin,Seismological study on the crustal structure of Tengchong volcano-geothermal area,Acta Seismol.Sin.24(3)(2002)231-242(in Chinese).
[3]S.Z.Pan.F.Y.Wang,Y.H.Duan,X.G.Deng,X.H.Song,Y.L.Duan,Y.N.Sun,C.J.Zhang,Y.D.Yang,Y.R.Zang,Basement structure of southern Yunnan and adjacent areas:the Zhengkang-Luxi deep seismic sounding profile,Chinese J.Geophys.58(11)(2015)3917-3927(in Chinese).
[4]P.Tapponnier,G.Pletzer,R.Armijo,On the mechanics of the collison between India and Asia,Geol.Soc.Lond.Spec.Publ.19(1)(1986)113-157.
[5]L.H.Royden,B.C.Burchfiel,R.W.King,E.Wang,Z.L.Chen,F.Shen,Y.P.Liu,Surface deformation and lower crustal flow in eastern Tibet,Science 276(1997)788-790.
[6]M.K.Clark,L.H.Royden,Topographic ooze:building the eastern margin of Tibet by lower crustal flow,Geology 28(8)(2000)703-706.
[7]W.J.Gan,P.Z.Zhang,Z.K.Shen,Z.J.Niu,M.Wang,Y.G.Wan,D.M.Zhou,J.Cheng,Present-day crustal motion within the Tibetan Plateau inferred from GPS measurements,J.Geophys.Res.112(2007).https://doi.org/10.1029/2005JB004120.
[8]P.Z.Zhang,Z.K.Shen,M.Wang,W.J.Gan,R.Burgmann,Z.J.Niu,J.Z.Sun,J.C.Wu,Continuous deformation of the Tibetan Plateau from global positioning system data,Geology 32(9)(2004)809-812.
[9]E.H.Zhang,H.Lou,S.X.Jia,Y.H.Li,The deep crust structure charcteristics beneath western Yunnan,Chinese J.Geophys.56(6)(2013)1915-1927(in Chinese).
[10]X.M.Xu,Z.F.Ding,F.X.Zhang,The teleseismic tomography study by P-wave traveltime data beneath the southern South-north Seismic Zone,Chinese J.Geophys.58(11)(2015)4041-4051(in Chinese).
[11]J.T.Pan,Y.H.Li,Q.J.Wu,Z.F.Ding,Phase velocity maps of Rayleigh waves in the southeast Tibetan Plateau,Chinese J.Geophys.58(11)(2015)3993-4006(in Chinese).
[12]M.Chen,H.Huang,H.J.Yao,R.Van der Hilst,F.L.Niu,Low wave speed zones in the crust beneath SE Tibet revealed by ambient noise adjoint tomography,Geophys.Res.Lett.41(2)(2014)334-340.
[13]Y.H.Li,Q,J.Wu,X.B.Tian,R.Q.Zhang,J.T.Pan,R.S.Zeng,Crust structure in the Yunnan region determined by modeling receiver functions,Chinese J.Geophys.52(1)(2009)67-80(in Chinese).
[14]C.Y.Wang,L.P.Zhu,H.Lou,B.S.Huang,Z.X.Yao,X.H.Luo,Crustal thicknesses and Poisson's ratios in the eastern Tibetan Plateau and their tectonic implications,J.Geophys.Res.115(B11)(2010).https://doi.org/10.1029/2010JB007527.
[15]D.H.Bai,M.J.Unsworth,M.A.Meju,X.B.Ma,J.W.Teng,X.R.Kong,Y.Sun,J.Sun,L.F.Wang,C.S.Jiang,C.P.Zhao,P.F.Xiao,M.Liu,Crustal deformation of the eastern Tibetan Plateau revealed by magnetotelluric imaging,Nat.Geosci.3(5)(2010)358-362.
[16]R.Li,J.Tang,Z.Y.Dong,Q.B.Xiao,Y.Zhan,Deep electrical conductivity structure of the southern area in Yunnan Province,Chinese J.Geophys.57(4)(2014)1111-1122(in Chinese).
[17]W.C.Yang,Z.Z.Hou,C.Q,Yu,3D crustal density structure of West Yunnan and its tectonic implications,Chinese J.Geophys.58(11)(2015)3902-3916(in Chinese).
[18]L.Y.Lu,Z.Q.He,Z.F.Ding,C.Y.Wang,Azimuth anisotropy and velocity heterogeneity of Yunnan area based on seismic ambient noise,Chinese J.Geophys.57(3)(2014)822-836(in Chinese).
[19]L.P.Zhu,H.Kanamori,Moho depth variation in southern California from teleseismic receiver functions,J.Geophys.Res.105(B2)(2000)2969-2980.
[20]C.Q.Li,X.Z.Sheng,M.Z.Qin,The effect of P wave velocity on the H-k stacking results of receiver functions,Acta Seismol.Sin.36(3)(2014)480-490(in Chinese).
[21]X.F.Zheng,Z.X.Yao,J.S.Liang,J.Zheng,The role played and opportunities provided by IGP DMC of China National Seismic Network in Wenchuan earthquake disaster relief and researches,Bull.Seismol.Soc.Am.100(5B)(2010)2866-2872.
[22]Y.Z.Wang,E.N.Wang,Z.K.Shen,M.Wang,W.J.Gan,X.J.Qiao,G.J.Meng,T.M.Li,W.Tao,Y.L.Yang,J.Cheng,P.Li,GPS-constrained inversion of presentday slip rates along major faults of the Sichuan-Yunnan region,China Sci.China Earth Sci.38(5)(2008)582-597(in Chinese).
[23]L.P.Vinnik,Detection of waves converted from P to SV in the mantle,Phys.Earth Planet.Int.15(1)(1977)39-45.
[24]Q,J.Wu,R.S.Zeng,The crustal structure of Qinghai-Xizang Plateau inferred from broadband teleseismic waveform,Chinese J.Geophys.41(5)(1998)669-679(in Chinese).
[25]J.C.VanDecar,R.S.Crosson,Determination of teleseismic relative phase arrival times using multi-channle cross-correlation and least squares,Bull.Seismol.Soc.Am.80(1)(1990)150-169.
[26]J.P.Ligorrna,C.J.Ammon,Iterative deconvolution and receiver-function estimation,Bull.Seism.Soc.Am.89(5)(1999)1395-1400.
[27]X.H.Zha,J.S.Lei,Crustal thickness and Poisson's ratio beneath the Yunnan region,Sci.China Earth Sci.43(3)(2013)446-456.
[28]G.Zandt,C.J.Ammon,Continental crustal composition constrained by measurements of crustal Poisson's ratio,Nature 374(1994)152-154.
[29]C.Zhen,The structure of the crust and mantle beneath Southeast Tibetan Plateau from receiver function and surface wave dispersion,Institute of Geophysics,China Earthquake Administration,2016(in Chinese).
[30]F.Y.Wang,S.Z.Pan,L.Liu,B.F.Liu,J.S.Zhang,X.G.Deng,C.J.Ma,C.J.Zhang,Wide angle seismic exploration of Yuxi-Lincang profile-the research of crustal structure of the red river fault zone and southern Yunnan,Chinese J.Geophys.57(10)(2014)3247-3258(in Chinese).
[31]Z.J.Zhang,Z.M.Bai,C.Y.Wang,Q.T.Lv,J.W.Teng,J.L.Li,S.X.Sun,X.Z.Wang,Crustal structure of Gondwana and Yangtze-typed blocks:an example by wide angle seismic profile from Menglian to Malong in the western Yunnan,Sci.China Earth Sci.34(5)(2005)387-392(in Chinese).
[32]S.W.Chen,B.S.Wang,X.F.Tian,F.Y.Wang,B.F.Liu,L.Li,Crustal structure from Yunxian-Ninglang wide-angle seismic reflection and refraction profile in northwestern Yunnan,China Seismol.Geol.38(1)(2016)91-106(in Chinese).
[33]Z.J.Zhang,Z.M.Bai,C.Y.Wang.J.W.Teng,Q.T.Lv,J.L.Li,Y.F.Liu,Z.K.Liu,The crustal structure under Sanjiang and its dynamic implications:revealed by seismic reflection/refraction profile between Zhefang and Binchuan,Yunnan,Sci.China Earth Sci.35(4)(2005)314-319(in Chinese).
[34]C.Y.Wang,H.Lou,X.L.Wang,J.Z.Qin,R.H.Yang,J.M.Zhao,Crustal structure in Xiaojiang fault zone and its vicinity,Earthq.Sci.22(2009)347-356.
[35]T.Xu,Z.J.Zhang,B.F.Liu,Y.Chen,M.H.Zhang,X.B.Tian,Y.G.Xu,J.W.Teng,Crustal velocity structure in the Emeishan large igneous province and evidence of the Permian mantle plume activity,Sci.China Earth Sci.45(5)(2015)561-576(in Chinese).
[36]Z.M.Bai,Deep Seismic Sounding Tomography:Research and Application,Institute of Geophysics,China Earthquake Administration,2016(in Chinese).
[37]N.I.Christensen,Poisson's ratio and crustal seismology,J.Geophys.Res.101(B2)(1996)3139-3156.https://doi.org/10.1029/95JB03446.
[38]Y.G.Gao,Y.H.Li,Crustal thickness and Vp/Vs in the Northeast China-North China region and its geological implication,Chinese J.Geophys.57(3)(2014)847-857(in Chinese).
[39]C.Y.Wang,H.Lou,Z.X.Yao,X.H.Luo,Z.Y.Lv,Crustal thicknesses and possion's ratios in Longmenshan Mountains and adjacent regions,Quat.Sci.30(4)(2010)652-661(in Chinese).