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THE INERPRETATION OF ERS-1 AND ERS-2 INSAR DATA FOR THE MINING SUBSIDENCE
MONITORING IN UPPER SILESIAN COAL BASIN, POLAND
Zbigniew PERSKI*
" University of Silesia,
Department of Geological] Mapping,
Bedziñska 60, 41-200 Sosnowiec, POLAND
erski@us.edu.pl
Working Group VII/6
KEY WORDS: Interferometry, Change detection, Deformation, Radar, ERS.
ABSTRACT
The successful application of the SAR Interferometry (InSAR) for interpretation of land subsidence, especially in
coal mining areas is described in this paper. The set of interferograms was collected in Poland over Upper Silesian
Coal Basin, where subsidence causes damages to buildings and changes of surface drainage patterns in a densely
urbanized area. InSAR is a technique, which uses the phase difference between the radar echoes from repeated SAR
(Synthetic Aperture Radar) images of the same area. InSAR is now a unique method, which gives us possibility to
take a measurement of land subsidence on a strict determined huge area of tenths thousand square kilometers and
a precision state in time range. Interferometric image of land subsidence over the SAR observation period of 35 and
70 days shows the subsidence increment on advancing slope of subsidence through. Elliptic-shape area of the presence
of subsidence is high correlated with the extent of the front of underground mining. It allows interpreting also non-
technological subsidence factors. The factors presented in this paper there are: lithology of cap rocks, dip of the coal
bank, presence of abandoned workings. The high valuable InSAR data can become in future the basic, independent
source of information about surface dynamics in Upper Silesian Region.
1 INTRODUCTION
In densely urbanized area of the Upper Silesia the subsidence due to underground coal mining affects an area of 600
km? each month and results deformations of the ground, and damages to buildings, roads and railways. The test
of applicability of ERS SAR interferometry (InSAR) for the subsidence detection in this area shows a high potential
of the interferometry (Perski 1998). Now, this work is continuated in AO3-127, a project of ESA 3rd announcement
of opportunity for exploitation of ERS data and aims to provide long-time monitoring of surface changes in the Upper
Silesian Coal Basin. In this project the results of ERS SAR interferometry are interpreted in conjunction with conventional
sources of the information about the subsidence, mining activity and geology.
2 METHOD OF THE STUDY AND ERS SAR DATA SELECTION
SAR interferometry is a technique to extract the high accurate information about vertical height changes of the Earth
surface using the phase difference between the radar echoes from repeated SAR observations of the same area. SAR
interferometry has demonstrated a high potential in measuring natural and man-induced surface movement (Massonnet,
Feigl 1998, Stow et al. 1999, Strozzi et al. 1999). Repeated ERS-1 and ERS-2 SAR observations of the selected test sites
in the Upper Silesia (Fig.1) have been used to process interferograms which present a pattern of elliptical fringes - the
indicators of the phase shift of radar signals caused by the mining subsidence (Perski, Jura 1999).
Despite the all-weather capability of space-born radar, the data availability in the case of the SAR interferometry
is strongly reduced by strict requirements with respect to orbital parameters, climatic season and daily weather conditions
(Tarayre, Massonnet 1994). One of the most important tasks in case of subsidence detection is the selection of best-suited
couples of SAR images, in order to minimize the influence of possible errors and to convince the observed fringe patterns
will represent only surface changes - i.e. the effect of mining subsidence.
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000. 1137
