Design of Field Instrumentation and Noise Removal Techniques for Seismoelectric Measurements

The weak amplitudes of seismoelectric signals have been a great source of difficulty in making meaningful measurements in the field. The pervasive natural and cultural electromagnetic noise is often two to three orders of magnitude greater than the seismoelectric signals sought, and traditional seismic or electromagnetic-electrical recording systems are not optimized for their measurement. The basic principles for acquisition of field data and the required instrumentation used to measure seismoelectric signals reliably are discussed in this section. We also illustrate the benefits of multichannel recording and dense sampling of the seismoelectric wave field for identifying different types of seismoelectric arrivals. Finally, we present recommendations for optimizing the removal of powerline noise by harmonic subtraction.