Crust and uppermost mantle structure of the Ailaoshan-Red River fault from receiver function analysis  

作　　者：XU Mingjie1, WANG Liangshu1, LIU Jianhua2, ZHONG Kai1, LI Hua1, HU Dezhao1 & XU Zhen1 1. Department of Earth Sciences, Nanjing University, Nanjing 210093, China 2. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 

出　　处：《Science China Earth Sciences》2006年第10期1043-1052,共10页中国科学（地球科学英文版）

基　　金：This work was supported by the National Natural Science Foundation of China (Grant No. 40034010).

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.S-wave velocity structure beneath the Ailaoshan-Red River fault was obtainedfrom receiver functions by using teleseismic body wave records of broadband digital seismicstations. The average crustal thickness, V_p/V_s ratio and Poisson''s ratio were also estimated. Theresults indicate that the interface of crust and mantle beneath the Ailaoshan-Red River fault is nota sharp velocity discontinuity but a characteristic transition zone. The velocity increasesrelatively fast at the depth of Moho and then increases slowly in the uppermost mantle. The averagecrustal thickness across the fault is 36—37 km on the southwest side and 40—42 km on the northeastside, indicating that the fault cuts the crust. The relatively high Poisson''s ratio (0.26—0.28) ofthe crust implies a high content of mafic materials in the lower crust. Moreover, the lower crustwith low velocity could be an ideal position for decoupling between the crust and upper mantle.

关 键 词：RECEIVER function  Ailaoshan-Red River fault  velocity structure  Poisson's ratio  CRUST and UPPER mantle. 

分 类 号：P542[天文地球—构造地质学]