On 29/3/2020 at 07:11:34 UTC (9:11:34 Italian time), an earthquake with magnitude M 3.4 (source: terremoti.ingv.it). occurred approximately 30 km west of Turin (Coazze). The seismic signal produced by this earthquake was detected by the stations of the Cornegliano Stoccaggio seismic network, which is approximately 170 km from the epicentre. Below, we show as an example the seismograms (daily traces in helicorder form) recorded at the OL02 station on the same day. The seismograms are filtered with a high-pass filter (above 1 Hz). The signal corresponding to the event is indicated with the arrow and is also recognizable in the seismograms from all other stations. Other signals that emerge from the background noise (such as the one at approximately 06:50 UTC) do not correspond to earthquakes but are ground vibrations due to causes of a presumably local nature not better identifiable and not significant with regard to the monitoring of Cornegliano Stoccaggio.

Daily tracks (vertical component) recorded on 29/3/2020 at the OL02 station, filtered with a high-pass filter at a minimum frequency of 1 Hz.