The combination of methods for analyzing the amplitude and phase of satellite radar images for the estimation of displacements on landslide-affected slopes
The efficiency of combining methods for analyzing the amplitude and phase of radar images from the ENVISAT, ALOS, and TerraSAR-X satellites is shown based on a case study of a landslide in Baranovka Settlement, Greater Sochi. The offset tracking method in the amplitude field of the reflected radar signal allowed us to define the contour of the area where the landslide occurred in the night between January 23 and 24, 2012 and to estimate the displacements in different parts of the landslide body. The maximum displacement was $7.5\pm1$ m. The displacements prior to the landslide from January 22, 2007 until September 17, 2010, as obtained from the ALOS satellite by the persistent scatterer method, demonstrate seasonal autumn-winter accelerations. The time series of displacements from the ENVISAT satellite shows that from November 29, 2010 until July 27, 2011 the displacement rates in the line-of-sight direction $v_LOS}$ were relatively small (21 mm/yr), but in the period from September 25, 2011 to December 24, 2011 the slide rate increased to 50 mm/yr. As obtained by the TerraSAR-X satellite, the slide rate $v_{LOS}$ after landsliding in the period from February 17, 2012 to March 10, 2012, reached 30 mm/month, but after June 6, 2012 it decelerated to 2--3 mm/month. Similar slide rates were also obtained for the same periods based on differential interferograms.