Advances, Problems and Prospects of Modern Geodesy Applied in Tibetan Geodynamic Changes

Abstract

Abstract:Modern geodetic techniques have developed rapidly in recent years, providing reliable observation data and new effective approaches, and greatly enhancing studies of the Tibetan geodynamics. For instance, the well‐known GPS technique has been employed to measure seismic slips for many faults in the Tibetan Plateau. GPS data agree well with the hypothesis of a thickening crust and eastward mass flow. Moreover, absolute gravimetric data have been applied to interpret geophysical phenomena such as crust movement, co‐seismic gravity change, GIA, and ground water change. The satellite gravity mission GRACE launched in 2002 provided global gravity models with unprecedentedly high precision and high spatial resolution. It has been used in implementing temporal gravity changes and improving our knowledge of the Earth's interior, including lithosphere dynamics, mantle viscosity and rheology, plateau uplift, and subduction processing. It is noteworthy that gravity presents unique advantages for the study of Tibetan geodynamics because of its sensitivity to mass migration and dynamic redistribution. To date, great advances have been made in applying modern geodetic data in studying dynamic changes of Tibetan plateau. For instance, the horizontal displacement field from GPS data revealed dynamical characteristics of the present‐day Tibetan plateau. The combination of gravity anomalies and topographic data describe the tectonic characteristics of Tibetan plateau. The combination of gravity data and GPS data show present properties of the Tibetan plateau such as crust thickening, Moho's subsidence, and plateau uplift. GRACE data were used to estimate the distribution of ice/snow melting. These results demonstrate that mere application of integrated geodetic data as well as geophysical methods and numerical simulations can enhance our knowledge of Tibetan plateau dynamics. It must be pointed out that GRACE data include various geophysical signals such as crust vertical movement, denudation, ice and snow melting, GIA, ground water change, and permafrost degradation. To separate the tectonic information from other impulses, each physical signal must be evaluated and corrected carefully from the GRACE data. The Tibetan geodynamic problem is a complicated and synthetic issue that must be addressed through collaboration of workers in many fields. Succinctly put, although great achievements have been made in studying Tibetan plateau dynamics from each field, the dynamical process remains unclear. Some fundamental problems remain unresolved. They should be solved with modern geodetic data, such as GRACE, GPS, and absolute gravity data, combined with meteorological and geological data, for quantitative analysis of Tibetan plateau dynamics affected by respective geophysical sources. This review article introduces and discusses the scientific importance, advances, problems, and prospects of modern geodesy applied to the study of geodynamic changes of the Tibetan plateau.