Commercial Systems
The only company found that produces a commercially available electroseismic prospecting system is GroundFlow Ltd. in the UK. This system has been mainly used for field demonstration purposes and research and development studies. Very few detailed case histories are available to web manual the performance of the system. The electroseismic system made by GroundFlow is called "GroundFlow 3000" and the main equipment components are:
- A combined computer-receiver
- Antenna cables and electrodes
- Trigger cable.
The computer-receiver contains a preamplifier, analog-to-digital converter and power supply system to measure the voltages induced in the grounded dipoles.
The hammer-and-plate seismic source is used along with two pairs of electrodes arranged in a straight line with electrodes offset (from the center of the array) by 0.25 and 2.25 m. The seismic source is positioned in the center of the array. Larger electrode spacing can be used; however, they are typically centered in pairs around the shot point and are generally less than about 10 m in length. Timing of the measurement is achieved by a hammer trigger (or other mechanical trigger). Measurements are made for a period of 400 ms after triggering. The last 200 ms of the record is used as a sample of background noise and is subtracted from the first 200 ms of signal in order to remove the first, third, and fifth harmonics of the background noise at the receivers. This noise is typically from power lines.
Read more about this topic: Seismoelectrical Method
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