The earthquake of magnitude 4.4 took place at Campi Flegrei in the night between 12 and 13 March and felt throughout the city of Naples is related, like the previous ones, to lifting the soil due to the phenomenon of bradyseism. In particular, in the last three weeks the lifting has undergone an acceleration: while until mid -February the average value of the lifting speed was 1 cm per month, now it is 3 cm per month. This increase in speed has been associated with a seismic swarm that at the moment appears finished.
Mahe what can this acceleration involve and what implies? Greater lifting speed could involve a greater number of earthquakes also of high magnitudeeven if it is not possible to determine when they happen how strong they will be. A faster deformation than soil does not mean that a volcanic eruption is imminent. Although in the last month a constant and rapid increase in lifting soil e gaseous emissions of volcanic origin, There is no evidence of a rise in magma. In this case, in fact, the monitoring networks of the Vesuvian Ingv-observatory would have found abnormal signals other than those compatible with a typical bradisismic crisis, such as the occurrence of low frequency earthquakes and the presence of anomalies in the appearance of deformations soil.
Possible earthquakes more numerous and intense to the Flegrei fields and to Naples
The quick lifting of the caldera of the last few weeks reveals an eco -contentment of the phenomenon of bradisism and could be accompanied by more numerous earthquakes of variable magnitudeeven high but in any case – it is supposed – not exceeding 5. In fact, there is a correlation between the deformation speed and the frequency of the seismes, since the lifting submits the rocks to more intense efforts leading them to fracture. In any case, it cannot be foreseen exactly neither when the seismes will happen nor how strong they will be. The lifting could also decrease In the coming weeks, since it is a process that undergoes fluctuations over time, even if the picture is that of a general lifting that continues since 2005.
The lack of evidence of the ascent of magma under the caldera of the volcano
The Monitoring networks Of the Campi Flegrei continually record the variations of the chemical-physical parameters in correspondence with the caldera. It has been seen that in the last seven years the concentration of co2 has increased considerably until it reaches 5000 tons per day and that of sulfur dioxide It has grown five times. This evidence, together with the constant lifting and frequent earthquakes, has aroused enormous concern in the population. However, the current events are still compatible with the phenomenon of bradisism e they do not imply an imminent volcanic eruption. These phenomena are the consequence of a increase in the rise of hydrothermal fluids issued by the magmalike water vapor, which causes an increase in pressure at a depth of about 4 km. The director of the Vesuvian Observatory Mario Di Vito, however, specifies that currently There is no evidence that with these fluids it also stands out magma.
What are the signs of a skill of magma that can indicate an eruption
As Mario Di Vito points out, at the Flegrei Campi the monitoring networks did not detect low frequency earthquakeswhich are one of the signs that promise the ascent of magma. This type of earthquakes are generated when the magma, exerting pressure on the rocks, the fractures penetrating inside them. At this point the magma can also cool in the fracture, in contact with the colder surrounding rocks, and stop. However, if the pressure is very high, the magma can go up further up to the surface generating a volcanic eruption.
If the magma dates back to a fracture, it would also produce ananomaly in the appearance of deformation soil, which would result from the satellite images and the data of the GPS sensors. Currently this anomaly does not result from monitoring.
In conclusion, at the moment we are in the presence of anIntensification of Bradisismas happened already in May 2024. It is also good to remember that during the 1982-84 bradisismic crisis, the lifting of the caldera even reached the 9 cm per month. The lifting phase could therefore end without eruptions, even if it is not possible to exclude that in the future they take place.
