A new study of theIngv (National Institute of Geophysics and Volcanology), published in the magazine Nature Communications Earth & Environmentprovided detailed 3D images of the internal structure of the Caldera dei Campi Flegrei up to a depth never investigated before, equal to 20 km. The images were obtained through a particular geophysical technique, the Three -dimensional magnetelluric tomographyand show the Main magma accumulation areaincluded between 8 and 20 km deep, e channels which could facilitate the ascent of magma through the crust. Identify these structures and their characteristics serves better understand the mechanisms that regulate the volcanic system of the area and therefore provides fundamental information for correct Volcanic risk management.
The study of the Caldera with magnetalluric tomography
The study of the Ingv had the purpose of reconstructing the internal structure of the magmatic system of the Caldera dei Campi Flegrei up to 20 km deep. To do this, the researchers applied 288 km to an extended area2 The technique of Three -dimensional magnetelluric tomographywhich measures the variations of electromagnetic fields of the subsoil generated by external natural sources. The analysis of the different frequencies allows you to define the distribution in the subsoil of the physical parameter called electrical resistivity up to a depth even of hundreds of kilometers. This parameter is important because it varies according to the materials: for example, water has low resistivity, while the rocks have a higher resistivity (variable based on the type of rock). The presence of fluidsincluding those of magmatic origin, is therefore easily identifiable thanks to theirs low resistivity. By mapping the variations of this parameter, the geophysics have therefore been able to create a three -dimensional model of the subsoil Of the Flegrei Campi, which highlights the size and geometry of the magmatic system, its volcano-tettonic characteristics and in general the distribution of the different rock materials.
What reveals the 3D model of the Caldera
The model shows a low resistivity area that extends between 8 and 20 km of depth, which corresponds to the main area of accumulation of partially merged rocks. From this area a low resistivity structure is developed similar to a channelin which it is located partially melted material: This channel could facilitate the transfer of magma and gas through the earth’s crust. Above the main accumulation area there is a medium resistivity area, rich in fluids and in which they are distributed small accumulations of magma in cooling in the shape of a lens. More on the surface there are then side bodies of solidified magma and a clay central coverage.
These results represent an important step forward in understanding the mechanisms that regulate the volcanic system and consequently in the monitoring of the caldera as explained by Roberto Isaiahone of the authors of the study:
Understanding the internal architecture of the volcano is essential to evaluate the current processes and provide useful indications to the scientific community and risk management.
