Modeling results of seismoelectric signals excited by a weight-drop source

This dataset contains data of all figures in a submitted manuscript titled "Refining higher modes of Rayleigh waves using seismoelectric signals excited by a weight-drop source: study from numerical simulation aspect " to Journal of Geophysical Research: Solid Earth. Effective extraction of higher mode dispersion information has been a research hotspot in the study of surface waves. In this study, we introduce a novel approach of refining Rayleigh wave higher modes by using seismoelectric signals, namely, electromagnetic (EM) signals originating from seismoelectric conversion. Adopting a weight-drop source, we simulate seismic and EM signals for a homogeneous half-space and six multi-layered porous models (see data for Figure 1). An extended version of the frequency-Bessel transform method is introduced to extract dispersion information from seismic and EM signals.

Using a homogeneous water-saturated half-space porous model, we firstly investigate the dispersion characteristic of seismoelectric signals in the simplest case and also give the physical explanation for seismoelectric signals induced by both seismic surface waves and body waves (see data for Figure 2). Then, we consider two-layer and four-layer half-space porous models whose top layer possesses the zero coupling coefficient to further investigate the dispersion characteristic of evanescent seismoelectric waves (see data for Figures 3-9). We find, in comparison with seismic waves, the evanescent seismoelectric waves contain extra Rayleigh wave dispersion information involving higher modes and different frequency ranges. To investigate the effect of the water saturation of the partially saturated porous medium, we design another four-layer half-space porous model whose top layer has a water saturation greater than the residual water saturation and three thirteen-layer half-space porous models with different variation range of water saturations for the porous media above the water table (see data for Figures 10 and 11). Besides, we also discuss some issues worthy of practical application and further study, including spatial aliasing analysis and the effects of electrode distance, electric background noise, salinity, and fluid viscosity on the electric fields (see data for Figures 12-17).

Generally speaking, our study suggests Rayleigh wave dispersion information with abundant higher modes and good frequency-range coverage can be obtained by using seismic and seismoelectric signals together due to their complementarity. It has the potential to significantly reduce the nonuniqueness and to increase the stability and accuracy in the dispersion curve inversion of Rayleigh waves.