M40

The Mini-Geophone M40 is used to receive P- and S-waves in horizontal boreholes. The borehole geophone consists of a tri-axial sensor. The geophone is coupled to the borehole wall by a pneumatic clamping system (inflatable bladder). Air is supplied to the M40 through the cable. The orientation of the M40 geophone is controlled from surface by a torsionally stiff hose. The cable is terminated by a connector to the seismograph.

Technical Details

Geophone sensor: GS14-L9
Natural sensor frequency: 28 Hz
Sensor arrangement: Tri-axial
Operational depth: Up to 10 m
Receiver length: 405 mm
Receiver diameter: 42 mm
Receiver weight: 3 kg
Cable weight per metre: 480 g
Borehole diameter: 50 mm (or larger if spacers are used)
Clamping system: Inflatable bladder
Orientation: Torsionally stiff hose
Depth indicator: Cable marking every 2 m
Connector: To any seismograph