Surface-wave Dispersion Stacking on a Granite-micaschists Contact at Ploemeur Hydrological Observatory, France
S. Pasquet, L. Bodet, L. Longuevergne, A. Dhemaied, F. Rejiba, C. Camerlynck and R. Guérin
Event name: Near Surface Geoscience 2012 – 18th European Meeting of Environmental and Engineering Geophysics
Session: Developments in Shallow Seismic
Publication date: 03 September 2012
Info: Extended abstract, PDF ( 2.31Mb )
Price: € 20
In the context of a geophysical survey at the Ploemeur hydrological observatory (France), we performed surface-wave profiling for the characterisation of shallow subsurface Shear-wave velocities. Since we anticipated lateral variations but needed great investigation depth, we deployed multifold acquisition geometries and used roll-along dispersion stacking to enable efficient measurements of multi-modal dispersion data. Several offset moving windows have been tested. Represented as pseudo-sections, the phase velocities extracted using a 12-trace window clearly showed three areas coherent with field observation and interestingly consistent with electrical conductivities and P-wave first arrival times. This cross-quality control has been of great help in the choice of the moving window size and revealed itself to be a rewarding step prior to the inversion process.