Atmospheric effects in SAR interferometry, implications on interpretation and modeling surface deformation: a case study of the 1999 (Mw=7.4) Izmit earthquake, Turkey
Ziyadin Cakir(1) and Rolando Armijo(2)
Cedex, 67084 Strasbourg,
(2) IPGP, Institut de Physique du Globe, 75252 Paris, France
Analysis of the coseismic interferograms of the 1999 Izmit, Turkey
earthquake reveals that the interferograms include atmospheric signal
correlated with topography. The phase-elevation ratio decreases with
increasing elevation, reaching up to 6 cm of relative phase delay.
Although the phase-elevation ratio also varies laterally, a simple,
horizontally uniform model for atmospheric effects is calculated using
a digital elevation model. Correction of the observed interferograms
with the model reveals that some of the anomalies in the fringe
pattern, which were previously interpreted to be the sign of triggered
slip, are most probably due to the changes in atmospheric conditions.
The model not only explains the wide spread noise, deflection and
bending in the fringes of the observed interferograms, but also reveals
some large scale artefacts previously undetected.
Keywords: ESA European
Space Agency - Agence spatiale europeenne,
observation de la terre, earth observation,
satellite remote sensing,
teledetection, geophysique, altimetrie, radar,
chimique atmospherique, geophysics, altimetry, radar,