The comparison of two differential interferometry techniques for the monitoring of geodynamic events

Abstract

The Synthetic Aperture Radar (SAR) data acquired from the satellites ERS–1 and ERS–2 facilitate the extensive and astonishingly precise investigation of small displacements of the Earth’s surface. Measurements of displacements are possible by differential SAR interferometry (D–InSAR) with centimeter accuracy. A detailed description of the D–InSAR system is presented to clarify the basic observation procedure. The D–InSAR system is an extension of the operational InSAR processor “GENESIS“ developed by the German Aerospace Research Establishment (DLR). The modular concept of the D–InSAR system permits a choice of different algorithms. Accordingly, the displacement can be extracted from an interferogram using a digital elevation model (DEM) as well as from two interferograms. Both techniques are illustrated and compared by a common data set. The geocoding and the various visualizations of the resulting data set support an easy application of this monitoring procedure in geosciences. Iceland is an especially suitable test site for differential SAR interferometry, because of its active tectonics, volcanism and flowing glaciers. Results of two Icelandic test sites are presented as applications.