One of the problems confronting the crosshole test interpreter is that of S-wave arrival identification. Unlike the P-wave, whose arrival appears first on the seismic record, the S-wave must often be enhanced to be recognized within existing wave trains. This can best be accomplished by designing a seismic source rich in S-wave energy. Further, since the polarity of an S-wave can be controlled (unlike the P-wave) the seismic source can provide positive identification if it is capable of S-wave phase reversal.

This product is designed to offer S-wave enhancement and phase reversal,signal repeaability, reliability, light weight, and low cost. Weak P-waves are also generated, and may be adequate for closely spaced boreholes.

This tool's basic concept incorporates lessons learned by its designer in his more than thirty-five years of practical experience in crosshole testing for engineering purposes. It is important to note that even though this tool is waterproof, the design is optimized for use in a dry cased borehole. If practical, water should always be removed from the seismic source borehole for best results. Turbulence in a borehole water column caused by the hammer activation can create undesirable noise.

This borehole seismic source uses an inflatable sidewall anchor system to provide positive borehole clamping. A three-in-one, 0.5 in. dia. cable houses controls for reversible spring loaded hammer activation, zero-time geophone and air for the clamping mechanism. Thus the problem of multi-cable tangling is eliminated.

The compactness of this tool enables a one or two person field crew to perform tests to depths of more than 150 feet without tripods or special purpose handling equipment.

List Price: $10,000
Includes 100 feet of cable, spare parts kit, spacer for 4" hole, and reusable shipping container
Additional cable $15.75 per foot. Specify length at time of order.