The failure of the sounding assumption in electroseismic investigations

The electrokinetic sounding (EKS) technique is a surface electroseismic technique based on the<br>assumption that the observed electroseismic signal is generated at positions vertically below the<br>seismic source. However, recent field observations and a simplified electroseismic model cast<br>considerable doubt on the validity of this assumption. The model shows that strong electroseismic<br>signals may be recorded at surface positions vertically above positions where no electroseismic energy<br>conversion takes place.