| 摘要 |
<p>The measurement equipment serves to map the subsurface geology in a terrain by means of electrical profiling. A plurality of drag electrodes (15a, 15b; 16a, 16b) are used for this purpose, said electrodes, with specific mutual spacing, being hooked together with a tow (9) in the form of e.g. a rope or a wire which is towed by a towing means (10). An electrical current, which is so low (less than 10 milliamperes) as to constitute no danger to the operators, is transmitted into the earth through the current electrodes (15a, 15b), and the voltage is measured across the voltage electrodes (16a, 16b). To prevent the operators from being injured, the current circuit includes a current limiter in the form of e.g. a constant current generator (17). With a view to separating the useful signal the voltage circuit includes a bandpass filter (19 and 20). Furthermore, a single-ended electrode amplifier (18) is incorporated in each of the voltage electrodes (16a and 16b). The method is useful for rapid and detailed mapping of deposits of natural resources, moist site areas, sand and clay localities in connection with road construction and building land, as well as water magazines and refuse dumps.</p> |
