Seismic Modelling of a Rising Mine Water Table

In former deep coal mining areas in Germany the mine water table is regulated by a water pump system such that the drinking water at the earth’s surface is not influenced. Nevertheless, it is planned to reduce the pumping rate in selected areas or to stop the pumps completely. Thus, the mine water table will rise and will effect the hydrogeologic situation at the surface. To minimise critical changes it will be necessary to determine the effects of a rising mine water table in advance. For a detailed forecast the exact depth of the mine water table has to be monitored during the rising process for the modelling of possible changes at the earth’s surface. To avoid the construction of expensive and complicated drill holes down to more than 1000 m depth an alternative technique to monitor the rising of the mine water table could be the time-lapse seismic. This method will have to be adjusted to the special situation of the water saturation in the surrounding rock materials due to the rising mine water table. The influence of the water saturation on the reflectivity of seismic waves is discussed with the results of seismic modelling.