Detection of electromagnetic anomalies of three earthquakes in Mexico with an improved statistical method

A method for detecting seismomagnetic signals is presented. This work presents evidence of geomagnetic perturbations associated with three earthquakes (EQs) that occurred in Mexico within a distance of rho = (1.8) 10(0.45M), where M is the magnitude of the EQ, during the year 2010. An improved statistical analysis in relation with the polarization analysis (as the ratio of vertical magnetic field component to the horizontal one) has been developed. The variation index (S-4) shows important differences one day before and one day after the EQs (magnitudes considered are from 6 to 7.2).