ST3 Seismograph with integrated 3D sensor 2 Hz frequency, 3 channel 24 bit

M.A.S.W. (Multichannel Analysis of Surface Waves):
The MASW (Multichannel Analysis of Surface Waves) technique has the objective to identify variation profiles with the depth of the speeds of volume waves (Vp and Vs).
The method is based on the known relations between these speeds and the dispersion of surface (or Rayleigh) waves observed when propagating through a stratified elastic medium.
The analysis can be based on signals produced with a borehole on site by acquisition device (with a ram or explosion), or on the recording of the vibrations produced by far away sources (rives, industrial activities, traffic, etc).

Nakamura Method, HVSR, H/V:
A significant part of the damages observed in destructive earthquakes all over the world is associated with the amplification of seismic waves due to the effects of the local site.
The analysis of the site response is therefore essential in the evaluation of the seismic risk in areas subject to earthquakes. In order to evaluate the effects of the local site, a series of surveys must be carried out.
Among the empiric methods, the method of spectrum analyses H/V on environmental vibrations is one of the most common. The method, also called “Nakamura” technique (Nakamura, 1989), was introduced by Nogoshi and Igarashi (1971) based on the initial studies of Kanai and Tanaka (1961). Since then, many researchers worldwide performed a large number of applications.