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 f...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.展开更多
基金supported by the National Natural Science Foundation of China(40874035)
文摘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.
