Moho Changes Beneath the Northeastern Tibetan Plateau Revealed by Multiple Geodetic Datasets

Abstract

SummaryThe Moho interface depths and variations provide important references to understanding the outward growth and expansion mechanisms of the Tibetan Plateau, which have drawn much attention. Here, we constrain the Moho variations beneath the northeastern Tibetan Plateau (NETP) by using multiple geodetic data and climate models. Hydrological and tectonic gravitational signals are identified from multisource data and removed from the satellite gravity observations. Moreover, the mass variation rate, resulting from vertical Moho changes is calculated. The result shows that the mass variation rate due to the Moho changes is 1.3 ± 0.6 mm/yr (equivalent water height) within the NETP, which corresponds to a Moho uplift rate of 2.7 ± 1.3 mm/yr. Additionally, we calculate the tectonic Earth surface uplift rate from GPS and leveling observations with loading and GIA (glacier isostatic adjustment) influence corrected, which gives an uplift rate of 2.2 ± 0.1 mm/yr and is similar with the Moho uplift rate. Our results indicate that the crust in the NETP is uplifted with a slight decrease in crustal thickness. Combined with the lithospheric structure from seismological tomography studies, we suggest that the crustal uplift of the NETP is mainly caused by isostatic adjustment since the delamination of the thickened lithosphere.