Seismoelectromagnetic effects associated with the 2017 February 15 Veracruz earthquake (Mw = 4.8)

Abstract

SUMMARY In this study, we investigated correlations between electromagnetic and seismic signals of the 2017 February 15 Veracruz, Mexico, earthquake (Mw = 4.8). We carried out a time–frequency misfit analysis based on the continuous wavelet transform in order to compare electric, magnetic and seismic records accurately. This analysis was performed for horizontal and vertical components separately. Our results from time–frequency misfit and goodness-of-fit criteria confirm the general similarity between seismic and electromagnetic signals both in frequency and time. Additionally, we studied the behaviour of peak amplitudes of seismoelectromagenetic records as a function of magnitude and distance. Our observations are in good agreement with previous studies, confirming scaling with magnitude and attenuation with distance. Radiated seismic energy estimations were performed with two methods: integration of velocity records and empirical Green function, respectively. Estimated energy magnitudes (4.35 < Me < 4.98) are consistent with reported seismic magnitudes for this event. We propose a method for determining electric and magnetic coseismic energies based on the concept of energy flux as implemented in the frequency domain by the integration of electromagnetic records. The calculated energies showed that the radiated seismic energy is much higher than the electric and magnetic energies.