Moho Interface Changes Beneath the Tibetan Plateau Based on GRACE Data
Weilong Rao, Wenke Sun
Abstract
Abstract The Tibetan Plateau (TP) experiences complex mass transfer and redistribution due to the effects of the internal Earth dynamics and external climate change, such as land water changes, crustal uplift, surface denudation, and Moho interface changes. These phenomena are accompanied by changes in the gravity field and can be observed by the Gravity Recovery and Climate Experiment (GRACE). This study uses GRACE data to estimate the mass changes expressed by the equivalent water height (EWH) anomaly of the TP. In addition, we use ICESat data and hydrological models to estimate the effects of hydrological factors (lakes, glaciers, snow, soil moisture, and groundwater) and to separate them from the comprehensive mass field to obtain the tectonic information. We found that the total hydrological contribution to the average EWH change is −0.27 ± 0.21 cm/yr. We further estimated a mean rate of 0.78 ± 0.06 mm/yr by interpolating the Global Navigation Satellite System (GNSS) velocities. Furthermore, large amounts of sediments have been accumulated on and around the TP because of TP's denudation, and the denudation and sedimentation rate were estimated in our study. By removing the effects of the hydrological changes, surface movements, and glacial isostatic adjustment (GIA) from the GRACE, we obtained the EWH change of 0.18 ± 0.22 cm/yr contributed by the interior mass change. We estimated a mean Moho interface uplift rate of 4.20 ± 5.13 mm/yr, and the distribution of Moho interface changes indicates that the northern TP's Moho interface is upwelling and the southern interface is deepening.