A Method for Extracting the Spectral Characteristics of Electromagnetic Emission Signals Recorded during the Loading of Rock Samples on the Technogenic Magnetic Noise Background

Nowadays, actively conducted research to study electromagnetic emission in the process of rocks, metals, composite materials’ samples loading as well as such emission in zones of rock massifs’ disintegration in sections of mine works are in progress. Measuring technique used for these purposes is aimed for recording electromagnetic emission signals mainly in the radio frequency range. The paper’s aim is to detect informative ultra-low-frequency electromagnetic radiation signals generated by a rock sample under the influence of an external load in the form of uniaxial compression created by a manual hydraulic press. The task of the study is to identify the detected low-frequency electromagnetic emission signals at the background of technogenic magnetic noise generated by a magmatic rock sample during its destruction and to establish their characteristic spectral features. The article presents results of observations of magnetic field variations using magnetic induction magnetomodulation transducers which allow recording and isolating informative signals generated by a rock sample under the influence of an external load in a laboratory experiment. The applied magnetomodulation transducers have sufficient sensitivity and resolution to record electromagnetic emission signals in the frequency range of 0.01–200 Hz, observed during the destruction of rock samples in process of their loading on the technogenic magnetic noise background. The paper describes the measurement technique, equipment and magnetometric apparatus, as well as the stages of software processing of initial data. The paper considers technique for identifying the informative ultra-low-frequency signal of recording the magnetic induction components generated by a sample of magmatic rock at its loading by uniaxial compression loading on the technogenic magnetic noise background. It was established that in case of destruction of the test sample during its loading the maximum amplitude of electromagnetic emission signals appeared in the ultra-low frequency part of the spectrum in the range of 0.3–4 Hz. Results obtained are important for studying the processes in the geological environment that generate low-frequency electromagnetic emission, as well as for investigating possible mechanisms of their generation.