DETERMINATION OF EXTENT OF THE SUBSIDING AREAS IN THE CZECH PART OF UPPER SILESIAN BASIN

Coal mining is carried out in the Czech part of the Upper Silesian Basin between cities Ostrava and Karvina on the area 80 square kilometres. Mining causes changes in landscape, especially the ground subsidence. The subsidence is located on the surface above the mined panels reaching its maximum within the first year after start of exploitation. Methods of satellite radar interferometry (Interferometry SAR -InSAR) was applied for the detection of subsidence for specific time periods. Using the differential interferometry SAR (DInSAR) is possible to determine the extent of subsiding areas for the processed time period (up to few months). DInSAR results for consecutive time-periods display the spatio-temporal evolution of the mining induced subsidence. The ground surface movements for longtime periods was determined by the PSI (Persistent Scatterer Interferometry) technique in built-up areas. Results of InSAR was necessary to compare and verify with results of other measurement techniques (levelling, GPS). In addition, the comparison of GPS (provided by IG ASCR) and DInSAR methods helped us to improve values of subsidence and the delimitation of the area affected by subsidence in the locality near Karvina. The geomorphological analysis has been carried out since the summer 2011 in the active mining area. One of the aims is to determinate and describe the subsiding areas belonging to particular exploited panels and to describe how the boundaries of subsiding areas are manifested in the relief. The analysis includes the study of relief changes of undermined area from air photos and from accessible elevation data.