Ebre seismic station (EBR)

The Ebre seismic station (EBR) is owned by the Ebre Observatory (OE) and is the first seismic station in Catalonia, installed in 1904 and still active. As the technology has advanced, the instruments have been updated and today it is still in operation thanks to the collaboration between the OE and the ICGC. You can consult here the lists and details of the seismographs previously installed at this station, as well as access to their scanned seismic records.

Geophysical characterisation

H/V Spectral ratio from seismic noise

H/V Spectral ratio of the seismic noise record at the Ebro Observatory seismic station. A peak around 0.5 Hz is observed which can be related to the fundamental frequency of the ground and, therefore, a contrast of acoustic impedance is expected in the subsoil.

Results of the H/V spectral ratio of seismic noise at the Ebre seismic station.

P-waves velocity  model

The P-wave velocity model (V_p) obtained through seismic tomography, is characterized by a package of low-velocity materials (V_P ​​< 2000 m/s) that extends up to 20 meters deep (rippleable materials). The depth of investigation of the seismic profile is not sufficient to detect velocities higher than 2500 m/s, velocity values ​​associated with the healthy rock that cannot be ripped and which can be interpreted as the bedrock.

Model of P-wave velocities for the seismic station of Ebre.

S-waves velocity model

In the shear wave propagation speed model (V_s) obtained using the array technique, a surface layer of 2 meters thickness and 200 m/s is observed. Below this layer, the speed increases to 750 m/s and extends to a depth of 30 meters. Below is a deep layer with a speed of about 900 m/s that extends to a depth of more than 400 meters. The bedrock is detected approximately 415 meters deep and has a velocity of about 2000 m/s.

Model of S-wave velocities for the Ebre seismic station.