<p>Short answer: 0.2 times the total length of your cable(s).</p>

<p>100m rollout --> ~20m depth</p>

<p>Bear in mind that the deeper you get, the more you have to be careful with your data interpretation. Also if you do a roll-along your depth doesn't get deeper. </p>

<p>Long answer see <a href="http://www.heritagegeophysics.com/papers/Depth_of_investigation.pdf" rel="nofollow">Bernard J (2003): Short note on the depth of investigation of electrical methods. Heritage Geophysics</a>.</p>

CC BY-SA 3.0
2014-10-15T22:40:36.537Z
2014-10-16T07:08:09.397Z
2014-10-16T07:08:09.397Z
mace
<p>In a resistivity survey, how do we calculate the depth of penetration for a Schlumberger array?</p>

CC BY-SA 3.0
2014-09-17T13:06:00.473Z
I thought I had this in a book (GSL Field Geophysics pocket book), but alas not. Of course the electrical field is continuous so you are going to have a depth that represents something like "half the sensitivity is shallower than this".
winwaed
<geophysics><measurements><in-situ-measurements><electromagnetism>
How do you calculate the depth of penetration in a Schlumberger array?
shrey
# How do you calculate the depth of penetration in a Schlumberger array?

(Asked by: username_0 on 2014-09-15)

In a resistivity survey, how do we calculate the depth of penetration for a Schlumberger array?

**Tags:** geophysics, measurements, in-situ-measurements, electromagnetism

> **Comments:**
> **username_1**: I thought I had this in a book (GSL Field Geophysics pocket book), but alas not. Of course the electrical field is continuous so you are going to have a depth that represents something like "half the sensitivity is shallower than this".  

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## 1 answers

### Answer by username_2 on 2014-10-15. Score: 4

Short answer: 0.2 times the total length of your cable(s).

100m rollout --> ~20m depth

Bear in mind that the deeper you get, the more you have to be careful with your data interpretation. Also if you do a roll-along your depth doesn't get deeper.

Long answer see [Bernard J (2003): Short note on the depth of investigation of electrical methods. Heritage Geophysics](http://www.heritagegeophysics.com/papers/Depth_of_investigation.pdf).


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