Investigation of Pre-Seismic Signals of Electromagnetic VLF Range Emission in Kamchatka

At the present time, great attention is given to the search for precursor anomalies in the electromagnetic emission of the very low frequency range and other geophysical signals. The paper presents approach to the study of the electromagnetic pulse structure based on sparse approximation. This approach showed good results in the processing of geoacoustic emission signals. It is assumed that the method will give good results in the study of the electromagnetic signals too due to similar typology of signals (pulsed nature). The authors use the Adaptive Matching Pursuit algorithm which provides an optimal ratio of the computational cost to the approximation accuracy for constructing a sparse signal model. The paper presents the results of processing of the electromagnetic signals recorded in the period preceding the Zhupanov earthquake on January 30, 2016. A comparison of anomalous sferics and background signals is made. A significant difference in their frequency-time structure is shown.