It is a passive seismic method which exploits environmental microtremors and is performed through standard instruments placed on the ground with linear array to get a good resolution in terms of frequency. it is important to use low resonance frequency geophones (4,5Hz are recommended), together with longer recording time of 15-30s compared to traditional seismic. In this way it is possible to record surface waves with a frequency range between 25-30Hz and 2 Hz which, in perfect conditions, provides a detailed reconstruction of Vs trend.


The survey equipment used by Geo Alps S.r.l. for performing refracted seismic surveys is composed by: 4 seismograph Seismic Source, Model DAQLink III, 24 channel, scan resolution 24 bit, with the following specifications:
Conversion A/D: sigma delta high speed converter 24 bit;
Background noise: 0.2 microVolt RMS (at 2 msec);
Accuracy trigger: +/- 1 microsecond at every frequency of sampling
Sampling rate: from 0.0208 to 16,0 milliseconds;
Sampling frequency: from 48.000 to 62.5 sample/second;


  • Determination of soil parameters such as shear modulus and Bulk modulus
  • Weathering/Fracturation
  • Distribution of geotechnical parameters
  • Mapping of decompaction zones (landfill)
  • Mapping of fault zones
  • Mapping of aquifer in gravels
  • Excavation (Rippability)