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Tremp Seismic Station (CTRE)

Code: CA.CTRE Name: Tremp 

Latitude: 42.3222 N Longitude: 0.7723 E Height: 1318 m

Local depth: - m

Owner: Institut Cartogràfic i Geològic de Catalunya

Subsoil features

Lithology

Period

Vs30 (m/s)

Classe EC8

F0 (Hz)

Limestones

Cretaceous

1100

A

-

Instrumentation by channels and periods

Channels

Start date

Sensor type

Digitizer type

Instrumental response

HHZ, HHN, HHE

01/07/2006

Broadband velocimeter

24 bits

[StationXML]

Geophysical characterisation

H/V Spectral ratio from seismic noise

H/V Spectral ratio from seismic noise records of Tremp 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 of seismic noise records from Tremp seismic station.

P-waves velocity  model

In the P-waves velocity model, obtained by seismic refraction tomography a first layer of a variable thickness is observed, between 1 and 3 meters, with a velocity lower than to 2000 m/s. These velocity values ​​correspond to ripable materials and can be related to fractured or weathered rock. In the area of ​​the seismic well the velocity values ​​exceed 3000 m/s at a depth of about 4 meters, velocities values ​​that are related to unweathered non-ripable rock.

P-waves velocity model of Tremp seismic station.

S-waves velocity model

From the analysis of surface waves (MASW) it has been possible to calculate the vertical profile of the velocity of propagation of shear waves (VS). Three layers are identified. The velocity of the shallowest layer is about 340 m/s with a thickness of 2 meters. Below this, it is observed a high-velocity layer, valued at about 1280 m/s, 28 meters thick. Finally, a last layer is identified, with a velocity higher than 2600 m/s.

S-waves velocity model of Tremp seismic station.