Measuring and interpreting this deformation is the key to understanding the geophysical processes at work and predicting future hazards. Precise terrestrial and satellite geodesy provides the tool to do this. Simultaneously, the driving force of geophysical study spurs further developments in geodetic analysis methods. We have for a number of years been conducting episodic GPS experiments to measure the long-term deformation of Greece . A further part of this research concerns the smaller but significant post-seismic deformation occurring in the few years after an earthquake, which provides information on the relationship between different layers in the Earth's crust.
Vertical movements play a part in work elsewhere, and demand slightly different analysis techniques.
We are using continuous GPS to measure long- term vertical movements due to oil extraction at a number of platforms in the harsh remote environment of the North Sea. To carry out this work we must maintain a GPS base station at Morpeth to IGS standards. Where vertical movements are larger and vary more rapidly, as in volcanic and coastal erosion situations, kinematic GPS provides an alternative.