Influence of the Phase Transitions of Water in Permafrost on Natural and Technological Electromagnetic Fields

Abstract

Frozen ground deformations, resulting from the volumetric changes, associated with the phase changes of water are accompanied by the phenomenon of electromagnetic emission. Based on monitoring data from an experimental site near Yakutsk, this study has shown that the vertical component of magnetic field strength increases at low frequencies in the spectrum of accepted signals in the spring and autumn periods. Seasonal increases in the natural electromagnetic field are attributed to electromagnetic emission which is observed in the frequency range 5-300 kHz when permafrost soils thaw or freeze. Monitoring data on the seasonal increase of natural and technological fields, strength at low frequencies, are presented. In sandy soils, the relative increase of the natural field was 543 % during thawing in May and 208 % during freezing in October. The relative increase of the field strength of a radio station was 1014 % in May and 178% in October. Electromagnetic emission in sandy soils was found to result in a twice higher relative increase in natural magnetic field strength upon thawing than upon freezing. The relative increase in magnetic field strength of radio stations is six times greater during spring thawing compared to autumn freezing. This is explained by better conditions for radio wave distribution on the line during the spring