Passive Seismic Investigations
HVSR Horizontal to Vertical Spectral Ration
Microtremor analysis technique (also known as Nakamura technique) aimed at determining the natural frequency of vibration of the ground in a certain site and based on the Fourier analysis of the microtremor components measured on the plane horizontal and in the vertical direction. HVRS passive seismic investigations enable the identification of the natural frequencies of resonance of lands. It is used above all in Seismic Zoning studies and for designing anti-seismic buildings. The versatility of this surveying method is also exploited to obtain the resonance frequencies of a building, which is then compared to that of the land. The technique involves obtaining recordings of environmental noise using a digital tromometer, connected to a seismograph.
Fields of application:
The fundamental resonance frequency (fR) of the subsoil.
Definition of Vs
Definition of Soil Classification
Study of landslides
Seismic Microzonation Study
Re.Mi. Seismic Investigations
This method, whose name stands for Refraction Microtremor, uses the same array as M.A.S.W., or seismic refraction, namely low frequency geophones, but instead of recording the seismic perturbation induced by energisation, it records micotremors over a time periods ranging from 20 to 30 seconds.
Fields of application:
Definition of Vs, eq
Definition of Soil Classification
Study of landslides
Modelling and study of Local Seismic Response
Seismic Microzoning
ESAC Seismic Investigations
This method records micotremors with geophones positioned in any 2D arrangement.
Fields of application:
Definition of Vs, eq
Definition of Soil Classification
Modelling and study of Local Seismic Response
Seismic Microzoning
SPAC Seismic Investigations
This method requires acquisitions obtained from circular arrays and is rarely used as it requires large spaces (the diameter of a circular array cannot be less than 50m).
Fields of application:
Definition of Vs, eq
Definition of Soil Classification
Modelling and study of Local Seismic Response
Seismic Microzoning
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We provide comprehensive assessments, for geological hazard assessments, geotechnical, material properties, stability of landslides and slopes, erosion, flooding, dewatering, and seismic investigations.
