Crust and uppermost mantle structure of the Ailaoshan-Red River fault from receiver function analysis |
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摘 要: | S-wave velocity structure beneath the Ailaoshan-Red River fault was obtained from receiver functions by using teleseismic body wave records of broadband digital seismic stations. The average crustal thickness, Vp/Vs ratio and Poisson’s ratio were also estimated. The results indicate that the interface of crust and mantle beneath the Ailaoshan-Red River fault is not a sharp velocity discontinuity but a characteristic transition zone. The velocity increases relatively fast at the depth of Moho and then increases slowly in the uppermost mantle. The average crustal thickness across the fault is 36―37 km on the southwest side and 40―42 km on the northeast side, indicating that the fault cuts the crust. The relatively high Poisson’s ratio (0.26―0.28) of the crust implies a high content of mafic materials in the lower crust. Moreover, the lower crust with low velocity could be an ideal position for decoupling between the crust and upper mantle.
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关 键 词: | receiver function Ailaoshan-Red River fault velocity structure Poisson’s ratio crust and upper mantle. |
收稿时间: | 18 January 2005 |
修稿时间: | 13 May 2005 |
Crust and uppermost mantle structure of the Ailaoshan-Red River fault from receiver function analysis |
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Authors: | XU Mingjie WANG Liangshu LIU Jianhua ZHONG Kai LI Hua HU Dezhao XU Zhen |
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Institution: | 1. Department of Earth Sciences,Nanjing University,Nanjing 210093,China 2. Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China |
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Abstract: | S-wave velocity structure beneath the Ailaoshan-Red River fault was obtained from receiver functions by using teleseismic
body wave records of broadband digital seismic stations. The average crustal thickness, V
p/V
s ratio and Poisson’s ratio were also estimated. The results indicate that the interface of crust and mantle beneath the Ailaoshan-Red
River fault is not a sharp velocity discontinuity but a characteristic transition zone. The velocity increases relatively
fast at the depth of Moho and then increases slowly in the uppermost mantle. The average crustal thickness across the fault
is 36–37 km on the southwest side and 40–42 km on the northeast side, indicating that the fault cuts the crust. The relatively
high Poisson’s ratio (0.26–0.28) of the crust implies a high content of mafic materials in the lower crust. Moreover, the
lower crust with low velocity could be an ideal position for decoupling between the crust and upper mantle. |
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Keywords: | receiver function Ailaoshan-Red River fault velocity structure Poisson's ratio crust and upper mantle |
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