Obserwacja przemieszczeń pionowych powierzchni terenu wywołanych eksploatacją węgla kamiennego za pomocą zobrazowań interferometrii satelitarnej (pasma C i L) na przykładzie Górnośląskiego Zagłębia Węglowego

The mining exploitation of hard coal in Upper Silesia has been conducted since XIX century and continues to the present days. Different methods of monitoring subsidence of the earth surface were applied in this area, startingfrom analysis of topographic maps compiled in different period of time, precise levelling and GPS measurements. Nowadays satellite interferometry seems to be use- ful and effective tool for these purposes. PS data from ERS and ENVISAT satellites very well illustrate subsidence occurring in the active mining areas where subsidence does not exceed- 40 mm /yr. These data correspond very well with subsidencepredictive models prepared by mining companies. However, the Upper Silesian Coal Basin (USCB) mining area subsides even up to 600 mm/yr (locally even more). Therefore, it is necessary to apply a different methodology. One of the solutions to this problem could be differential interferograms obtainedfrom L-band SAR images. Combination of C-Band (ERS, Envisat) andL-band (ALOS) shows excellent results. C-band SAR satellites are useful for detecting smaller displacements; in contrary L-band satellites are able to monitor surface defor- mations in range of several decimetres, being possible to detect progress of mining front.