The technique and procedure described here can be performed with any model of Landmapper (older models ERM-01 and -02 or new ERM-03 and -04).
Manual VES” cable set made to measure 16 layers of topsoil down to approximately 9 m. The worksheets for pre-set electrode spacings in such cable re-calculating measured resistivities to apparent resistivity, see this Google Drive public folder for downloads: 1D-VES.
We developed and tested with LandMapper a 60m-long cable, measuring down to ~ 20 m for one custom hydrology project.
This manual VES technique is most convenient to use with three people. Follow step-by-step instructions and video below.
- On your site establish the center location for the VES profile. It is a center point between M2 and N2 in the diagram above. Here the person with LandMapper will stay and conduct measurements.
- Send two persons outward in a straight line from the center to unwind both red wires from the probe up to 14 m mark (last electrode) and insert electrodes in soil => A1 and B1.
- Measuring person grounds central black M1N1 electrodes at MN/2=1.0 m (green label, black wires). Connect black wires (MN) to MN- terminals of LandMapper.
- Connect red wires (AB) to AB- terminals of LandMapper.
- Take ER-reading at K0=1 and AB electrodes at 14 m.
- Move A and B electrodes to 12 m marks at both sides – take ER-reading.
- Continue until AB/2=6.0 m.
- Move MN electrodes to 0.5 m marks (black wire, green label) and AB to 5.0 m mark.
- Continue taken measurements until last AB/2=1.0 m. It is also the previous location of M1N1 electrodes for steps 3-7.
- Field ER-readings can be stored in LandMapper memory or recorded manually.
- The recorded ER-values need to be multiplied on appropriate K-coefficients. Use tables below or input in Excel file to carry out auto-calculations.
Field data recording table. You can print this table from the website or download Manual 1D VES workbook Excel files there is a table already pre-formatted to fit on the Landscape page.
AB | MN | The measurement from deep to shallow | |||||||
distances, m | m | # |
AB/2, m |
K-set |
K-taken |
ER-1 | ER-2 | ER-3 | ER-4 |
[A1B1] = 28 |
2.0 |
1 |
14.0 |
K0=1 |
1 |
10.41 |
|||
[A2B2] = 24 |
2.0 |
2 |
12.0 |
K0=1 |
1 |
27.47 |
|||
[A3B3] = 20 |
2.0 |
3 |
10.0 |
K0=1 |
1 |
102.8 |
|||
[A4B4] = 18 |
2.0 |
4 |
9.0 |
K0=1 |
1 |
15.75 |
|||
[A5B5] = 16 |
2.0 |
5 |
8.0 |
K0=1 |
1 |
13.49 |
|||
[A6B6] = 14 |
2.0 |
6 |
7.0 |
K0=1 |
1 |
10.26 |
|||
[A7B7] = 12 |
2.0 |
7 |
6.0 |
K0=1 |
1 |
21.28 |
|||
[A8B8] = 10 |
1.0 |
8 |
5.0 |
K0=1 |
1 |
30.07 |
|||
[A9B9] = 9 |
1.0 |
9 |
4.5 |
K0=1 |
1 |
12.29 |
|||
[A10B10] = 8 |
1.0 |
10 |
4.0 |
K0=1 |
1 |
13.73 |
|||
[A11B11] = 7 |
1.0 |
11 |
3.5 |
K0=1 |
1 |
15.37 |
|||
[A12B12] = 6 |
1.0 |
12 |
3.0 |
K0=1 |
1 |
62.18 |
|||
[A13B13] = 5 |
1.0 |
13 |
2.5 |
K0=1 |
1 |
16.02 |
|||
[A14B14] = 4 |
1.0 |
14 |
2.0 |
K0=1 |
1 |
26.04 |
|||
[A15B15] = 3 |
1.0 |
15 |
1.5 |
K0=1 |
1 |
18.18 |
|||
[A16B16] = 2 |
1.0 |
16 |
1.0 |
K0=1 |
1 |
18.18 |
Instead of writing ER values on the paper in the provided table, you can store ER in LandMapper’s memory. You still need to keep track of what cell # starts new VES profile and which K values had you used (those K1-K9 are stored indefinitely, but don’t change K in the middle of field trip).
Recalculation table. This table automatically recalculates field ER measurements taken in the table above (in Excel file). Here on website it just shows values of K-geometric coefficient (K-multiply) for pre-set distances among electrodes using formulas for Schlumberger and Wenner arrays.
AB | MN | Measurement from deep to shallow | Recalculate ER for VES interpretation | |||
distances, m | m | # | AB/2, m | K-multiply | K-taken | ER-1 |
[A1B1] = 28 | 2.0 | 1 | 14.0 | 306.3 | 1 | 3188.6 |
[A2B2] = 24 | 2.0 | 2 | 12.0 | 224.6 | 1 | 6170.4 |
[A3B3] = 20 | 2.0 | 3 | 10.0 | 155.5 | 1 | 15986 |
[A4B4] = 18 | 2.0 | 4 | 9.0 | 125.7 | 1 | 1979.2 |
[A5B5] = 16 | 2.0 | 5 | 8.0 | 99.0 | 1 | 1335 |
[A6B6] = 14 | 2.0 | 6 | 7.0 | 75.4 | 1 | 773.59 |
[A7B7] = 12 | 2.0 | 7 | 6.0 | 55.0 | 1 | 1169.9 |
[A8B8] = 10 | 1.0 | 8 | 5.0 | 77.8 | 1 | 2338.1 |
[A9B9] = 9 | 1.0 | 9 | 4.5 | 62.8 | 1 | 772.21 |
[A10B10] = 8 | 1.0 | 10 | 4.0 | 49.5 | 1 | 679.36 |
[A11B11] = 7 | 1.0 | 11 | 3.5 | 37.7 | 1 | 579.44 |
[A12B12] = 6 | 1.0 | 12 | 3.0 | 27.5 | 1 | 1709.3 |
[A13B13] = 5 | 1.0 | 13 | 2.5 | 18.8 | 1 | 301.97 |
[A14B14] = 4 | 1.0 | 14 | 2.0 | 11.8 | 1 | 306.78 |
[A15B15] = 3 | 1.0 | 15 | 1.5 | 6.3 | 1 | 114.23 |
[A16B16] = 2 | 1.0 | 16 | 1.0 | 2.4 | 1 | 42.836 |
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