The seismic swarm continues in the Campi Flegrei area, with over 150 earthquakes occurring in about five hours. An initial 3.5 magnitude quake was felt in Naples. The ground started shaking again from 7:51 PM on Monday, May 20, and in the following minutes; then a strong tremor occurred around 8:10 PM, with a magnitude of 4.4. This is the strongest quake in the last forty years, the most intense since the resurgence of the bradyseism phenomenon in Campi Flegrei. The previous record dates back to the earthquake on September 27, when the recorded magnitude was 4.2. Another strong earthquake (magnitude 3.9) occurred at 9:46 PM, and yet another, with a magnitude of 3.6, at 11 PM.