Deep Electrical Conductivity of the Archaean Blocks of Kola Peninsula in the Light of the Results of Murman-2018 Experiment: A Review

A Spherical “Earth–Ionosphere” Model for Deep Resource Exploration Using Artificial ELF-EM Field

“…There are two methods to solve this problem: the first one is assuming that atmospheric and Earth layers are relatively flat; the other is to consider the spherical atmosphere and the Earth, and thus obtain a spherical harmonics series solution in a spherical coordinate system [10]. Since the pioneering works of J. R. Wait [11], J. Galejs [12], Bannister [13], J. P. Casey [14], and Pan and Li [15], many theoretical studies on ELF electromagnetic waves have been performed for different fields, such as communication [14,16], earthquake monitoring [17][18][19], geophysical exploration [20][21][22][23][24], and so on. It is clear that the ELF-EM method is an effective tool for probing the deep underground in a variety of geologic settings [20].…”

“…Since the pioneering works of J. R. Wait [11], J. Galejs [12], Bannister [13], J. P. Casey [14], and Pan and Li [15], many theoretical studies on ELF electromagnetic waves have been performed for different fields, such as communication [14,16], earthquake monitoring [17][18][19], geophysical exploration [20][21][22][23][24], and so on. It is clear that the ELF-EM method is an effective tool for probing the deep underground in a variety of geologic settings [20]. Considering that the skin depth increases as frequency decreases, ELF waves at a proper frequency can penetrate several to ten kilometers below the Earth's surface [8,25], and therefore the received response contains rich information about the deep stratigraphic structure.…”