Llívia seismic station (CLLI)

Geophysical characterisation

H/V Spectral ratio from seismic noise

H/V Spectral ratio using seismic noise records from Llívia 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 Llívia seismic station

P-waves velocity  model

The P-waves velocity model, obtained by seismic tomography technique, provides information about the behaviour of the subsoil up to 30 meters deep. In the resulting model , Vp increases gradually distinguishing 3 layers: a recent 3-5 m soil layer with little compactness with Vp less than 2000 m/s, the completely to moderately altered substrate with Vp between 2500 and 3000 m/s up to 10 m deep and, finally, the unaltered substrate up to the bottom of the model achieving Vp values above 3500 m/s.

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

S-waves velocity model

The S-waves velocity model resulting of the surface waves analisi (MASW) consist of two layers: Vs1=980 m/s for the unconsolidated soil and the altered substrate, and Vs2=2300 for the bedrock.

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