Near surface seismoelectrics in comparative field studies
In porous saturated media, seismic compressional waves can cause measurable electric signals via electrokinetic coupling. Despite increasing interest in the seismoelectric method, little material has been published on actual field measurements. In order to address this deficiency, several sites in Northern Germany were visited at different times to investigate the repeatability and variability of these seismoelectric signals. In general, there is a strong correlation between the overall quality of seismoelectric data and the quality of the associated seismic data. Factors like the electrical resistivity or electrode coupling are less significant. A strong dependence of the seismoelectric signals on the pH value could be shown with borehole seismoelectric measurements. A hodogram analysis of three-component seismoelectric data reveals that the polarization mainly follows theoretical predictions. The measurements, interpretations and comparisons with other methods presented in this work will help to assess the chances of successful application of seismoelectric measurements in near surface geophysical studies.