Detection of the Natural and Man-Made Cavities in a Urban Area in Lower Austria

Natural and man made cavities in an urban area constitute an important risk for the buildings. The cavities in the underground cause lowering then again different damages on the buildings. The activities for the preservation of the buildings and the estimation of the risk requires information about positions and dimensions of the cavities. In an urban area the investigation of the all geophysical methods is very difficult or often impossible. In order to detect the cavities in the urban area Marienhoehe/Maria Enzersdorf in lower Austria, which have induced a lot of damages on the buildings, seismic, resistivity and ground penetrating radar (GPR) are applied. In particular it was possible to localize zones with cavities by seismic methods. Subsequent the specifically targeted drillings confirmed the results of the seismic measuring. They prove the existence of natural and man-made cavities in gypsum which are accrued by mining activities more than one hundred years ago.