Magnetotelluric and Seismic Noise Techniques Combination for the Cerdanya Basin Characterization (Eastern Pyrenees)
B. Benjumea, A. Macau, A. Gabàs, J. Ledo, P. Queralt and S. Figueras
Event name: Near Surface Geoscience 2013 - 19th EAGE European Meeting of Environmental and Engineering Geophysics
Session: Geophysics in Engineering Geology (P)
Publication date: 09 September 2013
Info: Extended abstract, PDF ( 657.78Kb )
Price: € 20
A sedimentary Tertiary basin filled with unconsolidated sediments located in eastern Pyrenees has been subjected to a combine passive geophysical survey in order to increase knowledge of bedrock geometry and sediment properties. The methodology consists of combining and integrating both seismic noise techniques (H/V and array) and audio-magnetotelluric (AMT) and magnetotelluric (MT) data. AMT and MT data have been recorded along a NW-SE profile crossing the basin. Four 2D seismic noise arrays and 79 single station measurements were deployed at this profile. H/V technique has been suitable to obtain a soil fundamental frequency. Bedrock depth assessment can be obtained using S-wave velocity profiles derived from seismic noise array analysis. This information will allow establishing a soil fundamental frequency-bedrock depth relationship suitable for this basin. On the other hand, interpretation of the electrical resistivity model obtained from an AMT- MT survey will be constrained by the seismic results. This electrical resistivity model provides a detailed imaging of structural features such as the Cerdanya fault. This methodology, based on sediment characterization from shear-wave velocity and resistivity information, can be an attractive option for basin characterization essential for projects such as reservoir imaging.