Geophysical imprint of mining-induced rock mass deformation in the area of construction disaster in Bytom (Poland)

The paper presents the analysis of the results of geophysical surveys conducted in the mining area located in Bytom e Karb (USCB, Poland) in the aspect of identifying the causes of significant damage to the complex of inhabited tenement houses which occurred in 2011. The surveys were carried out by microgravimetric and GPR methods. The construction disaster was caused by the exploitation of one of the hard coal seams at a depth of about 800 m along the mining longwall running underneath the settlement. The terrain deformation parameters exceeded the forecasted values, and in several places discontinuities took linear forms along the diagonal directions to the front lines of the longwall. In addition to the sliding movement, the rotational movement appeared in the ground. As a consequence of spatially complex ground movements, some buildings suffered significant damage. The extent of the damage turned out to be catastrophic and immediate relocation of the inhabitants and demolition of the buildings became necessary. The article is an attempt to explain the nature and the causes of excessive terrain deformations in relation to those modeled on the basis of analysis and interpretation of geophysical data from the current measurements as well as archival maps and geological and mining cartography data.