Electromagnetic attenuation of eight earthquakes registered in Mexico using FFT-based spectrum and t-test statistical analysis for ULF Q-R ratios signals

• Main Authors: Omar Chavez, Jesus Roberto Millan-almaraz, Jose Antonio Lopez Cruz-abeyro, Eduardo Rojas
• Format: Article
• Language: English
• Published: Taylor & Francis Group 2016-07-01
• Series: Geomatics, Natural Hazards & Risk
• Online Access: http://dx.doi.org/10.1080/19475705.2015.1047903

A method to improve the detection of seismo-magnetic signals is presented herein. Eight events registered for periods of 24 hours with seismic activity were analyzed and compared with non-seismic periods of the same duration. The distance between the earthquakes (EQs) and the ultra-low frequency detector is of  ρ = (1.8) 100.45M, where M is the magnitude of the EQ reported by the Seismological National Service of Mexico, in a period of three years. An improved fast Fourier transform analysis in the form of the ratio of the vertical magnetic field component to the horizontal one (Q = Bz/Bx) has been developed. There are important differences between the frequencies obtained during the days of seismic activity compared with those with no seismic activity.