Electrical probing depth of ERT method
• Exploration depth depends on the maximum length measurement arrangement, rather than depending on the length of the survey line. Scroll measure does not increase the depth of exploration.
• In the number of electrodes and electrode spacing unchanged, diode array maximum depth exploration.
• In general, any exploration depth of a four-pole arrangement is about 15% to 20% of the maximum length of the arrangement, but the field should be more conservative design, the depth should be 10% to 15% of the maximum length of the study of the arrangement.
• Depth exploration of high-density electrical ground depends mainly on medium depth Edwards (1977) definition.
• The actual depth exploration of underground resistivity distribution of relevant, good guide will greatly reduce overburden depths.
• Exploration depth and the depth of the probe object associated with the ratio of diameter, the limit of this ratio is about 5.0
Order |
Median Depth |
Wenner (AMNB) |
17.3%of AB or 52% of a spacing |
Schlumberger |
19.1% of AB |
Gradient |
19.1% of AB |
Non-conventional |
19.1% of the largest electrode span |
Pole-pole(A-M) |
60% of AM |
Dipole-Dipole (AB-MN) |
14%~25% of the largest electrode span |
Pole-Dipole (A-MN) |
50%~60% of MN separation depending on
AM/MN |