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APPLICABILITY OF ERS-1 AND ERS-2 INSAR FOR LAND SUBSIDENCE MONITORING IN THE SILESIAN COAL 
MINING REGION, POLAND. 
Zbigniew Perski 
ESA fellow in ESRIN, Frascati, ITALY and University of Silesia, Faculty of Earth Sciences, Department of Fundamental Geology, 
Bedzinska 60, 41-200 Sosnowiec, POLAND 
perski@us.edu.pl 
ISPRS Commission VII, Working Group 6 
KEY WORDS: SAR, differential interferometry, mining, land subsidence, 
ABSTRACT 
In the study area in southern Poland some 130 Mio. tonnes of coal is extracted from 65 underground mines each year. As a 
consequence almost 6,000 sq. km of the Upper Silesian Coal basin is subjected to man inducted surface damages. The most 
dangerous factor is the land subsidence, causing damages to buildings and other constructions in a heavily populated area. 
The InSAR technique can be useful for monitoring the spatial distribution of mining subsidence and determine quantitative 
measuring for fixed time intervals. As an initial experiment, eight SAR images have been selected and five interferograms for 1 and 
2 months periods in 1992 and in 1995 have been processed. For the topographic effects removal a DEM from the ERS-1 and ERS-2 
tandem mission have been produced. 
Preliminary results are presented. On the interferograms from the 35-day periods in 1992 and 1993 subsidence effects have been 
identified, and a detailed interpretation and the comparison with ground data have been done. 
Initial interferometric tests show that InSAR technique can reveal spatial distribution of surface elevation changes due to mining 
activity. 
INTRODUCTION 
The Upper Silesian Coal Basin is located in south-central 
Poland. In this area the cities have an old mining tradition 
extracting since the Middle Ages silver, zinc and lead ore, and 
since the XIXth century coal . Due to this development the 
centre of Upper Silesia is very densely urbanised (4,000 citizens 
per 1 km2), and heavily industrialised. 
  
  
0% 0 
muo 
  
  
  
  
° 
"am 10 20 30 40 S0km 
N J 
Fig. 1: Location of the study area (black rectangle) on the 
bacground of the geological extent of the Upper Silesian Coal 
Basin and mining lease zones. 
  
  
  
The recent coal mines exploit 0.8 m to 8 m thick coal seams 
approx. 600 m under terrain surface. Each year these works 
cause Im of the earth surface subsidence. However, 
development of depressions can be often much faster, reaching 
1 to 3 cm per 24 hours. Such phenomena create huge hazards, 
especially for densely urbanised areas, what results damages to 
buildings and other constructions. Commonly subsidence is 
associated with sinkholing, deep fracturing of ground layer and 
changes in surface drainage pattern;. 
The problem of mining subsidence is as old as coal mining 
itself, but information on their extent is usually an unpopular 
item. Today, subsidence is calculated according to equation 
formulas: several empirical methods exists for prediction of the 
subsidence and for determination of the shape of depression 
(Kwiatek, 1997). The precision of the forecasting is controlled 
by geodetic surveying and shows ca 75% credibility of 
predictions. Such difference shows how complex are the natural 
conditions, especially for areas with multi-seam and multi-level 
coal extraction, espetially where old abandoned works are 
reactivated. 
The real extent of subsidence is never regularly surveyed on- 
site. The field measurements are done usually twice annually 
along selected traverses or around important engineering 
constructions (e.g. communication trails, factories, river banks). 
In the Upper Silesia no independent and spatially well 
distributed surveyor's network exist. 
REPEAT-PASS RADAR INTERFEROMETRY 
Repeat-Pass Radar Interferometry has a high potential for the 
measurement of land subsidence and other surface changes. It is 
a relatively new method but results of tests and experiments 
demonstrated the capability of this technique to measure man- 
inducted surface movement to centimetre resolution; e.g.: Bonn 
Experiment (Timmen et al., 1996), Urban Subsidence Mapping 
(Haynes et al 1997), subsidence at oil and gas exploration sites 
(van der Kooij et al., 1995, van der Kooij, 1997). Application 
of SAR interferometry to study the impact of underground 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXII, Part 7, Budapest, 1998 555