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S U M M A R YThe electrokinetic effect is one mechanism that causes the coupling between seismic and electromagnetic energies. This study deals with the numerical simulation of the electrokinetically induced coseismic electromagnetic fields associated with seismic waves created by a finite faulting in porous media. The key point of our numerical technique is to combine the point source stacking method with the Luco-Apsel-Chen generalized reflection and transmission method. After some validation test of our simulation method, we show several numerical simulation examples. Through a near-field model, we show that the point source approximation is not accurate in this configuration, as well as that the position of the rupture starting point and rupture speed obviously affect the coseismic EM fields. Then we numerically investigate the influence of different media properties on seismic waves and coseismic EM fields. We also carry out simulations of multilayer half-space models and show the characteristics of the coseismic EM fields. The preliminary results indicate that our numerical technique provides an effective approach of studying coseismic electromagnetic fields associated with seismic waves due to a finite faulting in porous media.

Magnetic mineral inclusions occur commonly within other larger mineral phases in igneous rocks and have been demonstrated to preserve important paleomagnetic signals. While the usefulness of magnetic inclusions in igneous rocks has been explored extensively, their presence in sediments has only been speculated upon. The contribution of magnetic inclusions to the magnetization of sediments, therefore, has been elusive. In this study, we use transmission electron microscope (TEM) and magnetic methods to demonstrate the widespread preservation of silicate‐hosted magnetic inclusions in marine sedimentary settings. TEM analysis reveals detailed information about the microstructure, chemical composition, grain size, and spatial arrangement of nanoscale magnetic mineral inclusions within larger silicate particles. Our results confirm the expectation that silicate minerals can protect magnetic mineral inclusions from sulfate‐reducing diagenesis and increase significantly the preservation potential of iron oxides in inclusions. Magnetic inclusions should, therefore, be considered as a potentially important source of fine‐grained magnetic mineral assemblages and represent a missing link in a wide range of sedimentary paleomagnetic and environmental magnetic studies. In addition, we present depositional remanent magnetization (DRM) modeling results to assess the paleomagnetic recording capability of magnetic inclusions. Our simulation demonstrates that deposition of larger silicate particles with magnetic inclusions will be controlled by gravitational and hydrodynamic forces rather than by geomagnetic torques. Thus, even though these large silicates may contain ideal single‐domain particles, they cannot contribute meaningfully to paleomagnetic recording. However, smaller (e.g., silt‐ and clay‐sized) silicates with unidirectionally magnetized magnetic inclusions can potentially record a reliable DRM.

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