The Ballard borehole seismic source is a special tool, often used for crosshole shearwave surveys, with a sliding weight that can hammer downward as the weight is allowed to drop or upward as the weight is pulled upward with a cable to create two shearwaves of opposite polarity. The opposite polarities of the shearwaves allow the user to identify this energy as opposed to the easily identified P-wave energy that appears first on a seismic record.
The Ballard source clamps to a borehole via an inflatable bladder. Its circumference is approximately 2.75 inches so it should fit in a 3 inch hole. Its inline spring-loaded hammer triggers an exploration seismograph via a 5000g shock rated geophone to take a reading while simultaneously producing a consistent and reliable energy source for surveys.
Ballard Borehole Seismic Source Packing List
1 x Ballard Source
1 x Air Pump
1 x Repair Kits and Manuals in Mesh Bag
1 x Mallet, 1 x Nut Driver, 1 x Needle nose Vice Grip
1 x Pelican Case 31x20x16, 65lbs
Ballard Borehole Seismic Source Specifications
Basic Tool Length – 24in
Body Diameter – 2.75in
Body Length – 15in
Cable – 0.5in diameter (length to suit)
Basic Tool 2.75 in. diameter – 12 lbs
Cable – 0.25lbs per foot
Center Frequency: Approximately 400 Hz
Trigger: Miniature, 5,000g shock-rated geophone 120 db dynamic range Waterproof (fully encapsulated in stainless steel housing) Bolted to upper anvil.
Sidewall Anchor System: Inflatable double-walled bladder, field replaceable Normal locking pressure, in an air-filled borehole-30 psi. Manual air pump & gauge.