What if we installed seismic sensors in Auvergne to listen to the sound of the waves in the North Atlantic?
It is crazy but it is possible!
Indeed, the variations in water height linked to storm waves in this region are like “hammer blows” on the seabed whose vibrations propagate over great distances and have a very specific frequency (0.2 to 1 Hz).
By placing 300 seismic sensors (Fairfield 1C nodes) during 1 month in a 700 km² area oriented NW-SE (noise direction), TLS Geothermics was able to record the propagation of these vibratory waves. The analysis of these recordings allowed Sisprobe to build a model of S-wave velocity: this is called ambient noise tomography.
Here, the fault model built independently of the geophysical data is superimposed on this S-wave velocity model of the studied area.