Questions regarding ERT.

Geophysical applications on environmental investigation, mineral prospecting, engineering, archaeology, forensics, hydrology...
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Questions regarding ERT.

Post by sayraleticia »


I have a Super Sting R1 which I am using to do groundwater exploration.

How far can I do an ERT from a cased water well? I need to do this to correlate the information and try to find similar values for the new well.

Some books mention that water should be between 10 ohm-m to 100 ohm-m, others to be on the safe side mention 20 ohm-m to 80 ohm-m. How do I define what value to look for?

Which text book do you recommend so I can learn more on ERT interpretation?

Is there any online training?

Thank you

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Re: Questions regarding ERT.

Post by panku44 »

When looking for water - you must remember that you are looking for geological layers that let water pass through. Different types of rocks have different resistances so there is no definite answer to your question. In layers Q - non-cohesive layers are permeable layers. Resistance values ​​for these layers are from 30ohmm (dust) to even 300ohmm (gravel). For different rock types, this resistance interval is even larger.
The problem of mineralization also occurs - with higher water mineralization, the resistance decreases - which can sometimes lead to mineralization errors.
For example, two profiles made in close proximity to each other but on two different river banks. Both profiles made with existing water intakes that have a capacity of about 30m ^ 3 / h - but the resistances are definitely different. In one of the wells there were significant exceedances of iron and manganese - hence the low resistances.

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