Analyzing earthquakes in a volcanic area can help improve the prediction of volcanic eruptions: this is stated by a recent study, entitled Earthquake frequency-magnitude distribution at Mount Etna sheds light on magma ascent in the volcano’s plumbing systemin which INGV researchers analyzed how the rise of magma underground influences the production of earthquakes on the basis of the so-called “value b“, a parameter that represents the relationship between the amount of low-magnitude and high-magnitude earthquakes. To do this, they took into account seismic data recorded between 2005 and the 2024 at theEtna. The parameter considered allowed for identify the movements of the magma from the deep crust to the surface. Its variations could constitute a precursor phenomenon of volcanic eruptions very significant, which would precede the gas emissions due to the rising magma by a few months.
The INGV study of earthquakes in the volcanic area of Etna
Monitoring of active volcanoes occurs through geological observations and the recording of physical and chemical data, which provide information on how magma moves in the superficial part of the crust. In this way they allow us to predict the release of magma to the surface only shortly before it occurs. THE magma movements in depthhowever, are more difficult to understand and detect. The new INGV study has the aim of analyzing what happens in the deep crust, in order to know well in advance what could happen on the surface in a volcanic area. The researchers analyzed the seismic data relating to Etnareferring to the period included between 2005 and 2024 and recorded by a seismic network of over 30 stations: these seismic events, over 20,500, had magnitudes between 0.1 and 4.8 and were related to three different crustal depths. In particular, the so-called “value b”, which describes how often low-magnitude earthquakes occur compared to high-magnitude ones. Changes in this parameter over time can indicate changes in the stresses to which the rocks are subjected of the crust along the volcano supply system, and therefore detect the movements of the magma from deep to superficial levels. These values, in the case of Etna, have allowed us to reconstruct the rise of the magma from the earth’s mantle, its accumulation at medium depths in the magma chamber and the subsequent rise from the magma chamber towards the surface.
The importance of the “b value” in predicting volcanic eruptions
The study showed that variations in the “b value” can precede gas emissions even by a few months due to the rising magma. This is possible because earthquakes reveal the movements of the magma at depth immediately, while the gases must rise for kilometers before escaping to the surface. According to the researchers, the monitoring of this parameter it could therefore integrate the standard one of the variation of chemical and physical parameters. However, it must be considered that the reliability of his analysis depends on theaccuracy of seismic monitoringin order to detect even the weakest earthquakes. For this purpose in the future theartificial intelligencewhich would allow many more seismic events to be detected and located. Monitoring the “b value” could therefore improve ours understanding the dynamics of magma And detect anomalies in advance which can lead to volcanic eruptions.
