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Surface-wave Dispersion Stacking on a Granite-micaschists Contact at Ploemeur Hydrological Observatory, France
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, Near Surface Geoscience 2012 – 18th European Meeting of Environmental and Engineering Geophysics, Sep 2012, cp-306-00023
- ISBN: 978-90-73834-34-7
Abstract
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.