On 18/12/2021, the Conegliano Laudense Seismic Network recorded a seismic event that occurred near Bonate Sotto in the province of Bergamo at 10:34:47 UTC (11:34:47 Italian time); it was an earthquake with magnitude ML 4.4 (source: terremoti.ingv.it). The event was felt in Milan and also throughout the Lombardia region. Although the event was located at approximately 50 km from the storage site, the seismic signal produced by this earthquake was detected by the stations of the Cornegliano Stoccaggio seismic network. The figure shows as an example the seismograms (daily traces in helicorder form) recorded at the OL08 station on the same day. The seismograms are filtered with a high-pass filter (above 1 Hz). The event took place in the context of a thrust fault near the contact between the Southern and Central Alps. The seismicity of the area, characterized by moderate magnitude, is documented in historical and instrumental catalogues (Boschi et al., 2000; Gruppo di Lavoro CPTI, 2004; Pondrelli et al., 2006; Guidoboni et al., 2007).