Ch 28. GNSS Geodesy in Geophysics, Natural Hazards, Climate, and the Environment

Introduction:

The original concept in the 1970s of a global positioning system as a real‐time positioning and navigation tool with several meters precision did not anticipate the major role that it would play in unraveling the complexities of tectonic plate motion, plate boundary deformation, volcanism, hydrology, glaciology, and climate, all applications requiring millimeter‐level precision. Space geodetic positioning provided the first direct measurement of tectonic plate motion; it was only a few years earlier when the theory of plate tectonics had become the paradigm for geologists and geophysicists. The primary advantage of GPS is that it provides highly accurate three‐dimensional positions and changes in position (displacements) of static, kinematic, and dynamic platforms with respect to a global terrestrial reference frame. Today, there are thousands of GPS stations at regional and global scales (Figures 28.1 and 28.2), and numerous precise GPS field surveys have been conducted (Figure 28.3). Increasingly, real‐time GPS observations are contributing to early warning systems for mitigating the effects of natural hazards such as earthquakes, volcanoes, and tsunamis.