Penetration characteristics of electromagnetic emissions from an underground seismic source into the atmosphere, ionosphere, and magnetosphere

Abstract

Theoretical calculations are made on electromagnetic fields in the frequency range 10−2 to 10−2; Hz on the ground surface and above the ionosphere induced by stochastic microcurrent activity inside the future seismic sources on the assumption of cylindrical symmetry of the effective current and three types of polarization. The inhomogeneity of the ground and atmosphere conductivity and anisotropy of the ionosphere are taken into consideration. The intensity of ULF magnetic and electric precursors observed on the ground, and their spatial distribution can be explained by using the results of the present computations. It is found that only the fields from a magnetic type source can penetrate into the magnetosphere and generate propagating Alfven waves. The expected values of magnetospheric electric and magnetic field are 1‐10 μV m−1 Hz−1/2 and 1–10 pT Hz−1/2 respectively, and the horizontal scale of their distribution is about 100–200 km. Finally, these theoretical predictions are compared with the corresponding results of satellite observations.

The LF radio anomaly observed before the M w = 6.5 earthquake in Crete on October 12, 2013

“…Thus, the anomaly in the MCO radio signal must be explained in terms of a different coupling mechanism. A satisfactory explanation for our anomaly is to assume that electromagnetic emissions, including the 216 kHz frequency, were generated during the pre-seismic phase in the epicentral area (Biagi P.F., 1999;Molchanov et al, 1995) and superimposed with the MCO radio signal in the area of the receiver. Thus, the MCO radio signal intensity could increase.…”

Analysis of the enhanced negative correlation between electron density and electron temperature related to earthquakes

“…From the observations of ionospheric perturbations associated with large earthquakes, several models have been proposed to explain the seismo-ionospheric coupling mechanism; these include an electromagnetic-wave-penetrating model from the lithosphere to the ionosphere (Molchanov et al, 1995), an acoustic-wave-propagating model (Hegai et al, 1997) and electrical-field-coupling models related to radon emission, aerosol accumulation, rock current and surface charge (Pulinets, 2004(Pulinets, , 2009Sorokin et al, 2007;Kuo et al, 2011). The last model plays an important role in explaining the ionospheric disturbances related to seismic activities in plasma parameters, such as the perturbations in GPS TEC (total electron content), foF2 and electron density; The histogram of distribution probability at different correlation coefficients before and after global earthquakes (in the right corner of the panel, the exponential decay has been fitted between the counts (variable y) and different coefficient scales (variable x); furthermore, the correlation coefficient R has been calculated).…”

Natural Electromagnetic Phenomena and Electromagnetic Theory: A Review

“…Further study is required. The propagation of ULF emissions from the lithospheric source to the ionosphere has been studied by means of the analytic electromagnetic method (31) , but there have been no detailed reports on electromagnetic computational studies of ULF propagation that take into account the realistic lithospheric structure as studied in the DC case. Electromagnetic computational analysis would be of essential importance in this study.…”