Active and Passive-Source Underground Seismic Data Acquisition

As part of the European research project Seismic Imaging Techniques for Mineral Exploration (SIT4ME), in-mine seismic active-source and continuous noise measurements were performed within an underground mine gallery of a former radioactive waste repository – the Asse II salt mine (Lower Saxony, Germany) to investigate its geological conditions. Inspired by recent underground active-seismic surveys in the Cote Blanche salt mine and former In-seam seismic surveys in the German hard-coal district of the Ruhr area, we apply conventional exploration and processing methods to an image of the subsurface. Among others, these include data sorting, bandpass filtering, normal moveout correction, static correction and depth (distance) conversion. To process the passive seismic data, we perform an illumination diagnosis for the retrieval of body-wave arrivals and apply passive-source seismic interferometry by cross-correlation (PSICC) on noise data dominated by S-waves. We show that active-source seismic measurements can be used from underground mine galleries for the identification of geological structures. Furthermore, we demonstrate that PSICC can be used to produce virtual-source underground seismic surveys resembling an active-source seismic survey.