GPS: Applications for measuring tectonic and fault-related deformation

The Global Positioning System (GPS) is a space-based Global NavigationSatellite System (GNSS). Using signals transmitted by GPS satellites, the positions of ground‐based receivers can be calculated to high precision,making it possible to track the movement of points on the Earth's surface over time. Unlike older geodetic surveying methods which involved periodicallymeasuring angles, distances, or elevations between points, GPS can provide three‐component (latitude, longitude, and altitude) position informationat a range of sampling rates and on a global scale. GPS equipment is easy to use and can be set up to collect data continuously. Since itsearly geophysical applications in the mid-1980s, this versatile tool, which can be used to track displacements over time periods of seconds to decades,has become indispensable for crustal deformation studies, leading to many important insights and some surprising discoveries.