Ingv researchers (National Institute of Geophysics and Volcanology) found that i stronger earthquakes In the Flegrei fields linked to the phenomenon of bradisism they are preceded by a few days or weeks from temperature variations at the ground level, analyzing the thermal images obtained thanks to Ecostress sensor of the International Space Station (ISS). The study, entitled At Novel Algorithm for Thermal Monitoring Using Ecostress Time Series: The Case of Campi Flegrei, Naples, Italy and published in the magazine Remote Sensing Letterssuggests that monitoring the Flegrei fields from space could represent an important step forward for theseismic alert of the area.
The thermal monitoring of the Campi Flegrei from space
The researchers took into consideration the thermal images of two areas of the Solfatara of Pozzuolimade between the 2021 and the 2022and have obtained the relative temperature data. The areas considered were those of the Big mouthseat of fumarole and main source of gas emissions, e Mudnot far from the big mouth and which does not show direct emissions of gas in the atmosphere. In these areas the temperature values are reliable because they are not influenced by the anthropic component.
In particular, the researchers analyzed the temperature differences between the two areas by resorting to 2 different statistical methodswhich make the interpretation of the data safer. This made it possible to detect Anomal temperature variations and to put them in relation to the strongest earthquakes Register in the Flegrea area.
The researchers analyzed the data collected by the tool Ecostress (Eco System Spaceborne Thermal Radiometer Experiment), a NASA-JPL sensor installed on International Space Stationwhich estimates the surface temperature of the soil With a high spatial resolution (about 70 m) making frequent steps on the same area (about 3 days). This tool, specifically, is a Multispectral thermal infrared radiometer (Truck) which provides images widely used in the analysis of the anomalies that precede earthquakes, in the detection of heat flows in correspondence with the volcanoes and in the mapping of lava flows.
The results of the INGV study on the temperature on the ground before the earthquakes
The study showed that the ground temperature has changed in the previous days or weeks to the SISMI considered. The magnitude 4.4 earthquake that took place on May 20, 2024, for example, was preceded by three days since a temperature increase of 5 ° C. The earthquake of magnitude 4.2 of 27 September 2023, however, was preceded by six days from an increase in temperature over 7 ° C. The last very strong shock, that of March 13, 2025, of magnitude 4.6, was not the subject of the study as it is too recent.
Anomalies have been identified by both statistical methods. It was also noted that the average value of the temperature difference is increased in recent yearstogether with the accentuation of the lifting of the caldera and the increase in carbon dioxide emissions. Cristiano Fidanithe Ingv researcher and co-author of the research said:
The temperature anomalies highlighted through two different statistical analyzes make us more confident about the possible link between the surface temperature fluctuation and the seismic activity of the area
This method, in essence, could help us predict a few days in advance the arrival of the stronger earthquakes. The goal is to alert the population as soon as possible.
