Inversion of Wrapped Differential Interferometric SAR Data for Fault Dislocation Modeling

The differential synthetic aperture radar interferometry (DInSAR) technique has dramatically boosted the application of remote sensing in many geophysical disciplines, particularly tectonics. Coseismic interferograms have provided, in many cases, "images of earthquakes," showing the surface displacement due to the deep fault dislocation. Aside from being visually appealing, such interferograms are of fundamental importance for the analysis, by means of appropriate dislocation models, of the geometrical and kinematic characteristics of the fault, which are also parameters of key interest for earthquake risk management. This paper provides a contribution in the general framework of the integration of dislocation models in DInSAR processing. In particular, with reference to coseismic interferograms, it proposes a technique that allows the direct inversion of wrapped interferograms for dislocation model analysis. This option makes it possible to avoid the critical and error-prone processing step of phase unwrapping, carried out in the classical analysis of interferometric data. Examples of inversion of real data, relevant to the 1999 Athens and Izmit earthquakes, demonstrate the feasibility and the advantages of this data processing approach.