Improving Near Surface Characterization by Combining Reprocessed Vintage Seismic and Geophysical Passive Datasets
B. Benjumea, A. Macau, A. Gabàs, M. Esquerda and S. Figueras
Event name: Near Surface Geoscience 2014 - 20th European Meeting of Environmental and Engineering Geophysics
Session: Seismics - Poster Session
Publication date: 08 September 2014
Info: Extended abstract, PDF ( 2.46Mb )
Price: € 20
This study reveals the importance of reprocessing vintage seismic data, originally focused on deep targets, in order to retrieve near-surface velocity model and structure. This information can be verified and complemented using cost-effective geophysical methods (passive seismic and audio-magnetotelluric - AMT data technique). This methodology has been applied to the Empordà Neogene basin (NE of Spain) where oil reflection datasets are available. 41 H/V stations were deployed along one seismic reflection profile to detect seismic impedance contrast between Quaternary/Neogene sediments and basement (Palaeozoic and Mesozoic). In order to calculate this contrast depth, shear-wave velocity profile has been obtained using seismic noise array technique. The final model obtained from the different seismic datasets show a basin shape with a gentle dip at the SW end of profile and an abrupt dip at the NE side interpreted as the Roses Fault. Bedrock depth reaches 660 m at the center of the profile according to H/V results. Finally, an AMT survey was undertaken at 10 sites to report a detailed 2D geoelectrical image across the Roses fault. The electrical resistivity model allows to characterize both structure and fluid properties associated with fractures network within the fault.