Gravity evidence of underplating in the northeastern margin area of Qinghai-Tibet plateau  

作　　者：Guo Shusong Hao Ming Zhu Yiqing 

机构地区：[1]Second Crust Monitoring and Application Center,CEA,Xi'an 710054,China

出　　处：《Geodesy and Geodynamics》2012年第3期46-50,共5页大地测量与地球动力学（英文版）

基　　金：supported by the National Natural Science Foundation of China(40874035)

摘　　要：Based on leveling data in 1972 -2011 and relative-gravity data in 1993 -2011, we obtained a longterm vertical crustal-deformation rate of 1.62mm/a and a relative-gravity variation rate of 0.62 × 10^-8 ms^-2a^-1 for the northeastern margin area of Qinghai-Tibet plateau. After removing the contributions from the observed vertical movement and inferred surface denudation, we obtain a gravity-variation rate of 0.73 × 10^-8 ms^-2a^-1 attributable to the mass changes beneath the crust. This positive change suggests that the total mass under the observation stations was gradually increasing. We consider this result to be the gravitational evidence of underplating beneath the study area, and propose that the underplating was caused by collision betwen the Indian plate and Tibetan plateau and by gravitation-potential induced deviatoric stress.Based on leveling data in 1972 -2011 and relative-gravity data in 1993 -2011, we obtained a longterm vertical crustal-deformation rate of 1.62mm/a and a relative-gravity variation rate of 0.62 × 10^-8 ms^-2a^-1 for the northeastern margin area of Qinghai-Tibet plateau. After removing the contributions from the observed vertical movement and inferred surface denudation, we obtain a gravity-variation rate of 0.73 × 10^-8 ms^-2a^-1 attributable to the mass changes beneath the crust. This positive change suggests that the total mass under the observation stations was gradually increasing. We consider this result to be the gravitational evidence of underplating beneath the study area, and propose that the underplating was caused by collision betwen the Indian plate and Tibetan plateau and by gravitation-potential induced deviatoric stress.

关 键 词：northeastern margin of Tibet plateau vertical crustal-deformation rate gravity variation field crust-mantle coupling UNDERPLATING 

分 类 号：P315.726[天文地球—地震学] P534.3[天文地球—固体地球物理学]