SEISMIC DOWN-HOLE/CROSS-HOLE TESTING
Instrumentation for geognostic investigation
This type of survey is performed through the physical –dynamic characterisation of the portion of ground between the two probing holes. The technique consists in the measurement of the travelling times of the elastic waves between the source located in a hole and the geophone/s located in another hole/s at the same depth. The cross-hole is made by introducing the borehole in one of the holes and the tridimensional geophone (or geophones) in another hole/s aimed at receiving the seismic signal incoming from the source at the same level. The elastic modules and mitigations of the medium between the holes can be obtained from this test.