The images obtained provide a vision of the internal structure of the Campi Flegrei, improving the understanding of the mechanisms that govern the volcano.
A new three-dimensional magnetotelluric tomography has provided an image of the internal structure of the Campi Flegrei caldera up to 20 km deep, a threshold never investigated before. This study provides detailed information on the entire structure of the caldera, including its submerged part, providing crucial new information on the magmatic processes that regulate the volcanic system.
A systematic review '3D magnetotelluric imaging of a transcrustal magma system beneath the Campi Flegrei caldera, southern Italy', conducted by a team of researchers from theNational Institute of Geophysics and Volcanology (INGV), In collaboration with the 'University of Oxford, Trinity College Dublin and the University of Munich has just been published in the journal Nature Communications Earth & Environment. The research results have provided new detailed images of the magmatic system present beneath the Campi Flegrei caldera, the volcanic system located northwest of the city of Naples.
"The Campi Flegrei may represent a natural risk due to the potential capacity to generate eruptions. For this reason, an accurate and constant understanding of their internal dynamics is essential. To this end, our study was conducted with the aim of reconstructing the internal architecture of the volcano's magmatic system up to 20 km deep, identifying the position and characteristics of the magma accumulation zones to better understand the mechanisms of transfer through the Earth's crust., explains Robert Isaiah, researcher at INGV and first author of the study.
To achieve these goals, the researchers used the magnetotelluric (MT), a geophysical methodology that measures the natural variations of electric and magnetic fields to reconstruct the electrical resistivity, a physical parameter of the subsoil very sensitive to the presence of fluids of different nature, including magmatic ones.
Thanks to the 3D inversion of electromagnetic data, the team was able to identify areas of accumulation and transfer of magma. The results obtained show areas compatible with the presence of partially molten material corresponding to volumes with low electrical resistivity, and channels of ascent that could facilitate the transfer of magma and gas through the crust.
"The tomographic image was obtained thanks to an advanced analysis of the data, processed with cutting-edge numerical modelling techniques.”, He adds Antonius Trojan, INGV researcher and co-author of the study. “The ability to detect areas with different physical characteristics up to 20 km deep is a significant step forward in defining the Phlegraean magmatic system and the possible routes of ascent. for magma and volcanic fluids".
“Investigating the Campi Flegrei was not only a scientific challenge, but also a logistical and technological one. The area is densely populated and subject to strong electromagnetic interference of anthropogenic origin, which makes data acquisition a complex undertaking. We have developed innovative acquisition protocols to ensure high-quality data despite the urban context.", points out Maria Giulia Di Giuseppe, INGV researcher and co-author of the study.
The current phase of unrest of the Campi Flegrei and the related concerns make this research extremely topical.
"Understanding the internal architecture of the volcano", explains Robert Isaiah, “it is essential to evaluate the processes in progress and provide useful indications to the scientific community and risk management".
The results obtained by the team of researchers represent a step forward in the development of more accurate predictive models and a fundamental piece in an increasingly refined monitoring framework.
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picture 1 - Relationship between seismicity distribution and resistivity anomaly. Panel (a) shows the map of the Campi Flegrei area, with the earthquake epicenters represented by white dots and the black lines indicating the a and b profiles used to extract the 3D resistivity sections. Panels (b) and (c) show the resistivity cross-sections along the α and β profiles, with the earthquake hypocenters superimposed (Md > 2,5, from January 2019).
picture 2 - Interpretative scheme of the magmatic system and deep structures beneath the Campi Flegrei reconstructed by 3D Magnetotelluric Tomography.