Civil engineering, Viaduct – Littoral road – Reunion Island (marine refraction, UMASW)


Objectives


In 2008, during the first geophysical studies about the coastal route at the Reunion Island (France), a marine geophysical measurements of the refraction and surface wave were carried out. This campaign was the first on this project using marine surface wave measurements. SismOcean, which performed these measurements, was interviewed by the local television Antenna Reunion.



Results

Marine seismic refraction gave access to vertical sections highlighting the geological units defined by the parameter of velocities of compression waves (P wave).


  • Seismic refraction (P wave velocities)


The marine surface wave gave for every seismic shot locations one or two vertical profiles of the shear wave velocities of the medium as a function of the depth. Locally inversion of velocities have been identified which is not possible by seismic refraction measurements.


  • Marine surface wave – UMASW (shear wave velocities)