Seismoelectric interface response signal behaviour in thin-bed geological settings

Abstract

Increasing industrial and societal challenges demand a continuous need for improved imaging methods. In recent years, quite some research has been performed on using seismoelectric phenomena for geophysical exploration and imaging. Like the other methods, the seismoelectric technique also has its drawbacks. Besides the fact that the physical phenomenon is very complex, one of itsmain challenges is the very low signalto- noise ratio of the coupled signals, especially the secondorder interface response fields. From seismics, it is wellknown that anonamously high amplitudes can arise due to amplitude-tuning effects which can occur when a seismic signal travels through a package of thin-layers with appropriate amplifying thickness. Using numerical seismoelectric wave propagation experiments through packages of thin-beds, we show that thin-bed geological settings can improve the signalto-noise ratio of the interface response fields. Whether a certain package of thin-beds results in a net strengthening or weakening of the signal, is determined by the contrast in and the order of the coupling coefficients of the different thin-layer media. Formulated differently, we show that the seismoelectric method is sensitive to the medium parameters of thin-bed geological structures far below the seismic resolution, and that due to natural strengthening of the seismoelectric interface response signal, the method might be already suitable for certain geological settings.