Site characterization

Rationale

Traditionally, they are determined through laboratory tests, which are influenced by sample disturbance. Mapping lateral sub-surface variations over larger areas requires integration of non-invasive seismic data with geotechnical boreholes. Complementing conventional seismics with surface waves can be beneficial for geotechnical and engineering applications, particularly when cyclic loading or vibrations play a role. Surface waves are dispersive, which allows establishing shear wave velocity profiles down to about one wavelength. At given frequencies, multiple propagation modes exist. Using these in inversion improves resolution, reduces uncertainty, and extends the investigation depth. Multi-modal inversion relies on novel forward modelling that accounts for the overlying water. In addition, the quality factors, being inversely proportional to material damping, can be determined from near-surface geophysics and can assist in soil characterization. 

Main Objectives

• Evaluate marine surface wave data acquisition;
• Develop algorithms to obtain shear wave velocities from multi-modal surface waves;
• Estimate quality factors from near-surface seismics;
• Bridge the gap between geophysical and geotechnical parameters.