Application of Permanent Scatterers on Mining Induced Subsidence
Michaela Kircher(1) and Achim Roth(2)
University of Bonn,
(2) German Aerospace Center (DLR), Oberpfaffenhofen, 82234 Wessling, Germany
Our study area is an active brown coal mining area in the Lower Rhine
Embayment, Germany. It is a rural area with moderate topography, and
divided in two big clods (the Erft-clod and the Cologne-clod) by NW-SE
striking faults. Groundwater withdrawal around the open cast pits has
led to wide spread subsidence, with a maximum subsidence rate of
approximately 10 cm per year.
Conventional Differential SAR Interferometry can hardly be applied to
study this area due to temporal decorellation. Therefore, we use the
Permanent Scatterer technique (PS), invented at POLIMI by Ferretti et
al., to analyze this area. The PS technique overcomes the problem of
temporal decorellation by only considering time-stable points in a stack
of many radar images. This technique has proven to be very well suited
for the analysis of urbanized area, and we have successfully applied it
to a more rural area.
Our first results are obtained using 40 ERS-1/2 images. An elliptic
subsidence bowl of approximately 18 by 12 km can be observed, which
agrees very well with available ground-based leveling data. Differences
in the deformation rate are in the order of a few percent.
Research is ongoing to improve the estimation and to investigate the
correlation between the structure of the subsidence bowl and the
regional tectonics by analyzing systematic changes of the displacement
rates on both sides of the faults.
Keywords: ESA European
Space Agency - Agence spatiale europeenne,
observation de la terre, earth observation,
satellite remote sensing,
teledetection, geophysique, altimetrie, radar,
chimique atmospherique, geophysics, altimetry, radar,