Geophysical Journal | 2009 volume 31 4

Spontaneous electromagnetic emission of the lithosphere: the state of the problem and mathematic models

© Yu.A. Bogdanov, V.N. Pavlovich, V.N. Shuman

The review is dedicated to natural electromagnetic disturbances of the radio-wave range (unites of kHz and higher), with sources located in the earth's lithosphere. The attention is focused on nonlinear aspects of mechanic-electromagnetic transformations in the earth's crust and the models of nonlinear interactions in the system of physical fields exchanging their energy with that one, accumulated by geological medium. Disputable problems of the theory have been noticed. Community of electromagnetic phenomena in geological medium is underlined. Special attention is paid to the processes of self-organization of geological medium as self-similar seismic-electromagnetic generating structure - the open system functioning of which is determined by global processes of energetic, degassing and dynamics of the Earth. Energetic pumping of geo-medium promotes formation of active systems, specific by nonlinear dynamics of physical fields and auto-wave mechanisms of fluids transfer. In such systems appearance of static, pulsing or running areas of fluid concentrations is possible, to which activation of mechanic-electromagnetic transformations is related. Associated acoustic-electromagnetic generated and emitted from these areas due to specific effect of self-induced transparency are exposed to the day surface and may be registered by devices. As generalization of theoretical works of this direction nonlinear parabolic equation of electromagnetic disturbances generation of the type reaction - diffusion is considered, which has in general case spatially localized, stationary or moving in a complicated manner solutions. It is noticed that based on this principle such special features of spontaneous geo-electromagnetic emission can be reproduced and understood as its impulse character, confinement of intensity bursts to fault zones - generators of disturbances and super remote distribution. Results of experimental observations on registering the signals of lithosphere origin and some examples of their practical use for diagnotics of structures are given.

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