Palau-saverdera seismic station (CPAL)

Geophysical characterisation

H/V Spectral ratio from seismic noise

H/V Spectral ratio from seismic noise records of Palau-saverdera seismic station. It is observed an almost flat curve, without any significant peak which might be associated to  the fundamental frequency of the soil. This behaviour is typical of rock sites.

H/V Spectral ratio curve using seismic noise records from Palau-saverdera seismic station

P-waves velocity  model

The P-waves velocity model, obtained by seismic tomography provides information of the subsoil up to 15 meters depth. A first layer of variable thickness is observed, about 5 meters, with a velocity lower than 2500 m/s. These velocity values correspond to rippable materials and can be related to a fractured or weathered rock. Even, the velocity of the most superficial level (about 2 meters) is lower than 1500 m/s in some sectors, which is associated with low compacted material. At the station site, the P-wave velocity exceeds 3000m/s about 7 meters deep, values that are related to non-rippable bedrock.

P-waves velocity model of Palau-saverdera seismic station, obtained by seismic tomography technique.

S-waves velocity model

From the surface waves analysis (MASW) a vertical shear waves velocity profile is retrieved (Vs). Two layers are identified: (1) the shallowest layer has a thickness of 15 meters and a velocity about 850 m/s. (2) Below, a high velocity layer is identified, with values higher than 2000 m/s.

S-Waves velocity model of Palau-saverdera seismic station, obtained from the analisi of surface waves (MASW).