Over 50,000 earthquakes occur every year on Earth. About a thousand of these are over magnitude 5 on the Richter scale and often cause damage to human settlements. The most powerful earthquakes, though rare, reach magnitude 9 on the Richter scale and cause devastation over kilometres.

Satellite data provide a unique opportunity to measure fine changes in the Earth's surface which are often precursors of an earthquake. Such data was produced by ESA with the Synthetic Aperture Radar instruments SAR and ASAR on ERS-2 and Envisat respectively. Monitoring earthquake prone regions with such instruments can assist in the forecasting of earthquakes, as well as in the management and evaluation of earthquake-associated risks.

With the launch of ERS-2 in 1995, a technique called SAR Interferometry (InSAR) became available. This technique involves combining two SAR images of the same area for use in displaying elevation or land change over time. This is obviously of particular use in the monitoring and analysis of earthquakes, as it can be used to pinpoint the extent of an earthquake and the variations in terrain.

Envisat was launched in March 2002, and carried the ASAR instrument, which sparked the interest for multi-polarisation. This uses PolInSAR (SAR Polarimetry and Polarimetric Interferometry) which can be used to combine multiple images of the same area, providing a more advanced application.