Using the list of the omega structures based on the The Magnetometers - Ionospheric Radars- Allsky Cameras Large Experiment (MIRACLE) network (Partamies et al. 2017), we obtained a number of important statistical characteristics describing the surface magnetic field. Based on 438 events, typical magnetic variation associated with the passage of the single omega were obtained. The typical variation, obtained using superposed epoch analysis, is associated with a local bending of the western electrojet and statistically confirms the distribution of equivalent ionospheric currents obtained in earlier observations of single omegas. It was found that during low and moderate geomagnetic activity, appearance of the omega structures in the dark morning MLT sector results in twice higher than average dB/dt on the ground surface. Also, the velocity, direction of movement , and area of omega structures were calculated. It is shown that faster and bigger omegas produce larger time derivatives of the ground magnetic field. Furthermore, we demonstrate that in the 03-08 MLT sector, superposed magnetic variations for the arbitrary events of very high time derivatives |dB/dt|>10nT/s, reveal magnetic signatures similar to omegas. Our findings, together with the results described in Apatenkov et al., 2020, emphasize the important role of omega structures in the formation of large geomagnetically induced currents.