Design for a Manually Controlled Multiple Electrode
Electrical Resistivity Array for Student Geophysical Surveys
Smoyer,
Justin,
Kuhn, Michelle, Friehauf, Kurt, and Quinn, Paul V. Sr, Dept. of Physical
Sciences, Kutztown University, Kutztown, PA 19530
To facilitate rapid
collection of electrical resistivity data for a groundwater study in
karst terrain, we designed and constructed a 56 electrode array
controlled with a manual switching box. The switchbox allows directing
current to electrodes using Wenner or Schlumberger arrangements for
vertical sounding on several centers after only one emplacement of
electrodes or Dipole-Dipole arrangements for measuring pseudo-sections.
The rate of data collection
improved most with longer node spacing and when operated by fewer
students because moving the electrodes was the slowest step in the data
collection procedure. Results of data for the same test site using
traditional four-electrode Wenner array to determined depth to the base
of the plow zone and depth to bedrock are virtually identical to those
measured with the big array (R-squared = 0.99).
The spacing between
electrodes is 3 meters, allowing a maximum spacing with the Wenner
array of 55 meters. Data analysis using a spreadsheet helps students
understand the concepts underlying their data interpretation. For
undergraduate student hydrogeology projects, the instrument is a low
cost alternative to commercial multi-node arrays and all materials are
readily available.
Northeastern Section–41st
Annual Meeting (20–22 March 2006)
Geological
Society
of America Abstracts with Programs, Vol. 38, No. 2, p.
89