A High-Order Finite-Difference Combined With Runge–Kutta Scheme for Full-Component Simulation of Seismoelectric Waves

Simulation of the seismoelectric effect is an effective approach for investigating the propagation characteristics of seismoelectric waves. However, the quasi-static approximation fails to capture the electric field associated with the S-waves, resulting in considerable errors in the simulation of coseismic responses. Additionally, the dispersion and dissipation errors in seismic waves caused by numerical schemes can induce errors in the resulting coseismic electromagnetic (EM) field, further affecting the accuracy of the interface responses. To mitigate these issues, we develop a finite-difference time-domain (FDTD) method that combines high-order differences on staggered spatial grids with Runge–Kutta (RK) time discretization (RK-HO-FDTD). The method is based on the 2-D dual-mode equations derived from decoupling the 3-D Pride’s equation and applies to full-component simulations of both the PSVTM and SHTE modes, thereby overcoming the limitations of previous 2-D single-mode methods. A comparative analysis with traditional methods demonstrates that the RK-HO-FDTD considerably improves simulation accuracy of seismic waves and reduces the coseismic response errors induced, thus contributing to the accurate simulation of interface responses. Moreover, the agreement between the simulation results and the analytical solutions in full-space and half-space models indicates that the method reduces errors in comparison to the quasi-static approximation and enables free surface modeling in both the PSVTM and SHTE modes. This method is further applied to layered and fluid anomaly models for full-component simulations, achieving the simulation of interface and coseismic responses. It provides a more accurate tool for full-component simulations of seismoelectric responses and has the potential to improve subsurface property detection and imaging.