Fig. 7
From: On the observation of magnetic events on broad-band seismometers
Low-frequency recording of the subway activity at the ICJA broad-band seismometer. Displayed data correspond to the vertical component of the seismic acceleration, bandpass filtered between 0.08 and 0.05 Hz. Each line shows 1 day, between September 27 and October 26, 2017. The different timetable of the subway system during the Friday and Saturday nights (orange and red boxes) is clearly shown by the seismic data. The night between the 11 and 12th October shows the same pattern than Fridays, as October 12th is a bank holiday in Spain