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.