o assess the effect of geomagnetically disturbed days on the amplitudes of the first three modes of the Schumann Resonance (SR), we analyzed 14-day periods of data around the day of a geomagnetic storm (GS) event. We considered Dst indices lower than ~ −70 nT corresponding to moderate to severe geomagnetic storms. To compare the behavior of the SR signal between days without disturbances in the geomagnetic field (quiet days) and days when a GS occurred (disturbed days), we analyzed data for the years 2015–2017 finding five 14-day periods of SR recorded data that were adequate to perform the analysis. In all cases we found a statistically significant increase (>1 sigma) during the geomagnetically perturbed days in the averaged amplitude of the three main SR frequencies of the horizontal magnetic field components. Such increase may be affected by other natural phenomena, such as lightning activity, measured by a local electric field monitor, or earthquake occurrence. We used data of a SR station located in Coeneo, Michoacán, México (geographic coordinates 19° 48′ 19″ N, 101° 41′ 39″ W; magnetic coordinates 29° N, 174° W; 1964 m asl).