Self-potential survey
Jouni Lerssi, Geological Survey of Finland, PO Box 1237, 70211 Kuopio, Finland; jouni.lerssi@gtk.fi
Description
The self-potential method makes use of natural currents flowing in the ground that are generated by electrochemical processes to locate shallow bodies of anomalous conductivity and water circulation. This is a method employing natural electric sources. Two natural potentials are mainly used in exploration geophysics:
- Electrokinetic (streaming) potential
- Mineralization potential.
These potentials are expressed in V or mV.
Appropriate applications
- Exploration of metalliferous mineral deposits
- Detection of water circulation into the ground
- Monitoring dams or tank integrity
Performance
- Depth of investigation depends on the size of the mineralized body and the depth of the water table for a mineralization potential (generally shallow, < 30 m).
- Interpretation mainly qualitative (profile, map).
- Quantitative interpretation using dipole approximations for the polarized body (similar to magnetic interpretation).
Design requirements
Fig. 1. Descriptive picture of non-polarizing electrone used in SP-measurements (© Riitta Turunen, GTK).
Fig. 2. Basic principle of measurement (© Riitta Turunen, GTK).
References
Reynolds, J.M. 2011. An Introduction to Applied and Environmental Geophysics. John Wiley & So n s Ltd, Chichester, 2nd ed.,712 pp.