Acta Geodyn. Geomater., Vol. 8, No. 3 (163), 319–323, 2011 APPLICATION OF PERSISTENT SCATTERERS INTERFEROMETRY FOR LANDSLIDE MONITORING IN THE VICINITY OF ROZNOW LAKE IN POLAND Zbigniew PERSKI 1) *, Andrzej BORKOWSKI 2) , Tomasz WOJCIECHOWSKI 3) and Antoni WÓJCIK 1) 1) Polish Geological Institute – National Research Institute. Carpathian Branch, Skrzatow 1, 31-560 Cracow, 2) Wroclaw University of Environmental and Life Sciences, Institute of Geodesy and Geoinformatics, Grunwaldzka 53, 50-357 Wroclaw, Poland 3) University of Silesia, Department of Fundamental Geology, Bedzinska 60, 41-200 Sosnowiec, Poland *Corresponding author‘s e-mail: zper@pgi.gov.pl (Received January 2011, accepted August 2011) ABSTRACT The paper presents the preliminary results of the analysis of two archival SAR datasets acquired by ERS-1/2 satellites of the same area of Roznow Lake in Southern Poland. Both datasets cover the same period of 8 years (1992 – 2000) and refers to the same area by the 50% of overlap between the neighbouring satellite tracks. The main purpose of this analysis was to derive the overlapping data about deformation velocity calculated using PSI (Persistent Scatterers Interferometry). The presented PSI results refer to PS (Persistent Scatterers) located on active landslides and therefore representing landslide movement. In Polish Carpathians, due to sparse urbanization, vegetation and rough relief the obtained PS density is usually not very high and generally difficult to interpret. The application of two overlapping datasets, where both of them observe the same phenomena, allow to cross-validate the data by identification of common PS points. For two datasets acquired from different tracks, usually many PS are not common and occur at different locations. Such situation could be explained by the difference between the incidence angles for both acquisitions. In a case of two tracks and therefore different terrain objects might act as PS. By joining the PS point sets from such neighbouring tracks the density of PS could be significantly increased. In order to perform a PSI analysis of Roznow Lake the data acquired from 179 and 408 tracks have been used and a few hundred of PS were obtained from PSI processing. For both tracks similar deformations velocity were obtained within a range of +/- 6 mm/yr. The PS points on active landslides are usually related to the buildings (walls, roofs) and roads affected usually by high risk. KEYWORDS: landslides, Persistent Scatterer Interferometry, SAR interferometry, LIDAR, Carpathians currently carried out mostly in the Carpathians. Another important goal of SOPO project is to establish monitoring systems on the particular landslides dangerous to infrastructure. Traditionally, to support geological and geomorphological analysis stereo-pairs of aerial photographs are applied. Recently analogue stereo pairs were replaced by digital photogrammetry and digital ortophotomaps with associated Digital Terrain Models (DTMs). Within a framework of SOPO project some advanced remote sensing techniques that might support landslide mapping and monitoring are currently tested. One of these techniques is Synthetic Aperture Radar (SAR) interferometry (InSAR) that utilizes phase information derived from satellite SAR images. InSAR has been already recognized as a very effective low-cost technique for landslide deformation detection and monitoring (Colesanti and Wasowski, 2006). The application of various SAR Interferometric (InSAR) techniques like Differential InSAR (DInSAR) (Achache et al., 1995), Persistent Scatterers Interferometry (PSI) (Colesanti and Wasowski, 2006) 1. INTRODUCTION Carpathian Mountains are subjected to high landslide geohazards. It is the area where more than 95% of the total number of landslides in Poland is located. Landside occurrence is here caused by the specific combination of the geological, geo- morphological and hydrogeological conditions. Landsliding activity is however controlled by hydrological factors like heavy rains and melting thick snow cover. Such events resulting acceleration and reactivations of landslides causing costly damages to built up areas and communication system. In last decades such situations occur in 1997, 2001, 2003 followed by catastrophic activity in summer 2010. Learning lesson from past landslide events the Polish Ministry of Environment together with Polish Geological Institute has initiated in 2006 the national project named “Landslide Counteracting System” (SOPO). The purpose of SOPO project is to create detailed maps and the digital database of all recently active and inactive landslide prone areas in Poland (Grabowski, 2008). The main part of the work is detailed field mapping in scale of 1: 10 000 and is