Fewer earthquakes and a slowdown in the rate of ground uplift.
The monthly surveillance bulletin for the Phlegraean Fields, issued by the Vesuvius Observatory, Naples branch of the INGV, for the month of September, confirms the "respite" granted by the bradyseismic phenomenon in the area.
Compared to the months of July and August, in which 668 and 634 earthquakes with a maximum magnitude of 4.0 were recorded respectively (on July 26 at 13.46 pm), during the month of September, 160 earthquakes with a maximum magnitude of 1.9 were recorded in the Campi Flegrei, 7 of which occurred during a seismic swarm that began on September 7 at 21.11 pm with its epicentre in the Solfatara area.
Also confirmed is the reduction in the speed of ground uplift, a phenomenon typical of bradyseism, which since the beginning of August has been around 10 millimetres per month at the Rione Terra Gnss station, the historic centre of Pozzuoli, compared to the average value of around 20 millimetres recorded from April to July 2024.
The total uplift of the ground at Rione Terra is about 15,5 centimeters since January 2024, a full 1,33 meters since November 2005, the beginning of the current “unrest” phase. The uplift also affected the seabed of the Phlegraean caldera: from 2006 to today, at the Pozzuoli Porto tide gauge station, a ground uplift of about 1,28 meters has been recorded, while from 2023 to today at the Cfba geodetic buoy located in the Gulf of Pozzuoli the uplift is about 24,5 centimeters.
“Based on the current picture of volcanic activity – the Vesuvius Observatory concludes – there are no elements that suggest significant short-term developments. Monitoring of the Phlegraean area remains at the Yellow alert level”.
