Measurement of small co-seismic deformation field from multi-temporal SAR interferometry: application to the 19 September 2004 Huntoon Valley earthquake

Interferometric synthetic aperture (InSAR) has been widely applied to natural disaster monitoring. However, it has limitations due to the influence of noise sources such as atmospheric and topographic artefacts, data processing errors, etc. In particular, atmospheric effect is one of the most prominent noise sources in InSAR for the monitoring of small magnitude deformations. In this paper, we proposed an efficient multi-temporal InSAR (MTInSAR) approach to measure small co-seismic deformations by minimizing atmospheric anomalies. This approach was applied to investigate the 18 September 2004 earthquake over Huntoon Valley, California, using 13 ascending and 22 descending ENVISAT synthetic aperture radar (SAR) images. The results showed that the co-seismic deformation was ±1.5 and ±1.0 cm in the horizontal and vertical directions, respectively. The earthquake source parameters were estimated using an elastic dislocation source from the ascending and descending acquisitions. The root mean square errors between the observed and modelled deformations were improved by the proposed MTInSAR approach to about 3.8 and 1.8 mm from about 4.0 and 5.2 mm in the ascending and descending orbits, respectively. It means that the MTInSAR approach presented herein remarkably improved the measurement performance of a small co-seismic deformation.