Specifics in the formation of substituence through in the Karvina part of the Ostrava-Karvina coalfield with the use radar interferometry
Jiránková, Eva; Lazecký, Milan
Deep extraction of minerals is accompanied by deformations of the strata overlying extracted
coal seams. Deformations of overlying layers run up to the surface where a subsidence trough
gradually forms. The movement of individual surface points is curvilinear, spatial and, in
relation to the time pattern, not uniform. In some cases, during the formation of a subsidence
trough, temporary uplifts of the surface occur. This paper gives a particular area in which uplifts
of the surface occurred when the rigid overlying strata was disturbed. The character of
deformations of the overlying rocks is evaluated on the basis of a comparison of the results of the
measurement of subsidence of the surface using geodetic methods with the development of
mined-out areas and with their extracted thickness. For specifying the time of failure of the
overlying strata, also information obtained from a system of continuous monitoring of seismic
events is used. The spatial extent of the subsidence trough is identified by satellite radar
interferometry (InSAR) techniques applied to TerraSAR-X images. The subsidence wave was
possible to detect using a short temporal difference of 11 days between satellite radar images.
This shows the potential of short-temporal high resolution InSAR for monitoring of progress of
subsidence troughs. A good knowledge of extents and shape of subsidence trough formation in
time allows to verify values of parameters used for prediction purposes. Application of the short
temporal InSAR appears very effective for spatio-temporal studies of the current subsidence
trough development and helps understanding the physical process as well as identifying
deviations from the behaviour expected by models.
↧