Insar analysis of the effects of the Izmit earthquake with ERS data

After the 17/08/99 earthquake in Turkey, ESA and CNES decided to coordinate their efforts for the emergency study of the earthquake effects based on satellite observations (ERS, SPOT). In particular, a set of archived ERS acquisitions over the interested sites was promptly provided by ESA, a series of tandem acquisitions were programmed (ERS-1 was switched on over Turkey) and the acquired post-event images were also made available. This allows not only for the study of the first seismic effects, but also for the evaluation and monitoring of the post-seismic deformations. For the particular case of the ERS-1 and ERS-2 orbits 30 and 31 days after the first earthquake, the orbit control strategy could exceptionally take into account InSAR requirements, obtaining minimal orbital baselines between co-seismic interferometric acquisitions over the site of interest. This paper will present part of the interferometric results obtained at CNES and ESA, using the best available dataset. Several interferograms are compared in order to take into account possible residual topographic effects, and analyse the effect of orbital errors or possible atmospheric artifacts. Further analyses based on different techniques are still ongoing at CNES, such as correlation of optical data and radar multitemporal analysis.