Cross-Hole survey consists in the direct
measurements of horizontally travelling
compression (P) and shear (S) seismic
waves at test sites consisting primarily of
A borehole seismic source is used to
generate a seismic wave train. One or
more receivers are used to detect the
arrival of the seismic wave train in offset
borings; the distance between boreholes
at the test depths is measured using a
borehole deviation survey.
Wave velocity is calculated from the
measured distance and travel time for
the respective wave train.
To generate P waves an automatic energy source,
SOLGEO SPARKER™ is used; it can work at many
different levels of power (from 100J to 350J)
ensuring frequency contents from 100 Hz up to 6
kHz; it must be used in boreholes filled with water,
up to 200 m depth.
An hydrophone is used as receiver of P waves in a
borehole filled with water.
SOLGEO GEOS-H™ is used to generate S waves;
it has the possibility to work in boreholes up to
200 m of depth also filled of water.
The energy source substantially is composed
by two parts: a central section, that contains
the pneumatic clamping assembly and second
part that contains the electrodynamics waves
generator. The device allows to automatically
produce both upwards and downwards signals,
in order to obtain an inversion of the shear waves
polarization without P waves noise.