Publication Date:
2016-05-14
Description:
In this work, we carry out numerical simulations of the seismo-electromagnetic fields associated with a fault in a porous medium by considering the electrokinetic effect. In addition to porous materials, the adopted layered models comprise solid materials in which the electrokinetic effect is inoperative. First, sensitivity study is performed for the evanescent and direct radiation electromagnetic (EM) waves generated by a double couple point source embedded in a porous half-space below a solid half-space. Results suggest that both the evanescent and direct radiation EM waves are sensitive to some medium properties, for example porosity, salinity, fluid viscosity, and conductivity of solid layer. Then, adopting an eight-layer half-space model, we simulate the seismic and EM wavefields generated by the rupture process of a finite fault. It is shown that the electrokinetic effect is able to generate observable corupture EM signals, but the observability depends on some factors such as the epicentral distance, properties of the medium where the fault is located, and local activity levels of EM noise. Time synchronization coseismic EM signals are recorded when the receiver is close to the ground water level but located in a solid medium. In addition to the post-seismic electric field, our results also show the post-seismic magnetic field which has not been identified in previous simulation studies on the electrokinetic effect. The generation of the post-seismic magnetic field probably requires a sufficiently strong medium heterogeneity or fluid-pressure gradient.
Keywords:
Geomagnetism, Rock Magnetism and Palaeomagnetism
Print ISSN:
0956-540X
Electronic ISSN:
1365-246X
Topics:
Geosciences
Published by
Oxford University Press
on behalf of
The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
