Detecting and monitoring of landslides using persistent scattering synthetic aperture radar interferometry

Persistent scatterer synthetic aperture radar interferometry (PSInSAR) is an applied time series technique to overcome limitations of InSAR (temporal and geometrical decorrelation and atmospheric delay anomalies) for monitoring of ground surface deformations. This method only monitors displacements on pixels with nearly constant temporal backscattering characteristics. In this study, datasets of ascending ALOS PALSAR (L-band) images recorded from 2006 to 2010 and descending ENVISAT ASAR (C-band) images acquisitioned between 2003 and 2010 were processed to detect and monitor the landslide occurred in the Noghol area, Iran. Application of the PSInSAR technique on both PALSAR and ASAR images has significantly improved monitoring of the Noghol landslide. However, the determination of vertical displacement of the landslide by the ASAR images processing is more correct compared to results of the PALSAR processing due to the descending orbital motion of ASAR. The ASAR images also overwhelm PALSAR images for determination of the landslide extent because of detection of more persistent scatterer points. The landslide displacement and aspect obtained by the Global Navigation Satellite System (GNSS) and PSInSAR techniques are in agreement (about 1.2–1.5 m westward in the period of 2003–2010). Particularly, processing results of the ASAR images are more similar to the GNSS measurements. Furthermore, assessment of the landslide type, mechanism and its displacement direction were possible by integration of the PALSAR and ASAR radar images with ascending and descending orbital motions, respectively.