Source: National Institute of Geophysics and Volcanology (INGV), 27/11/24
A team of researchers from the National Institute of Geophysics and Volcanology (INGV) recently conducted two different experiments aimed at understanding the deep nature of the subsoil by exploiting the peculiar geophysical characteristics of Sardinia, a portion of stable lithosphere in the middle of the constantly moving Mediterranean.
The two experiments, a gravimetric survey and a seismic array, were carried out in the disused mine of Sos Enattos (NU), the Sardinian site candidate to host the Einstein Telescope (ET) research infrastructure.
Thanks to the so-called “seismic silence” that makes the Sos Enattos site so special, these experiments will allow us to further expand our knowledge of how the Earth resonates in its depths.
The gravimetric survey, carried out in the two main extraction galleries of the former Sos Enattos mine, has provided a three-dimensional photograph of the structural layout in the subsoil. The researchers have carried out gravimetric measurements capable of detecting the presence of structures, faults, cavities and tunnels, all characterized by a different density. Being able to observe the different densities present in the subsoil allows to expand the results of the physical and geophysical experiments currently underway in the galleries of the former mine, strengthening the multidisciplinary scientific collaboration at the heart of the ET project.
As part of the Sardinia Far Fault Observatory (FABER), a second group of researchers from the INGV conducted another experiment with the aim of completing the map of environmental noise. In the Municipality of Bitti (NU), seventeen broadband seismometers (array) were installed according to a special “helix” configuration capable of capturing the high-frequency seismic noise that propagates in the first 200 meters underground. The instrumentation used, acquired as part of the PNRR Monitoring Earth’s Evolution and Tectonics (MEET) project, will return useful data for the study of the variations and sources of that “seismic silence” that makes the Sos Enattos site unique.
Some moments of the gravimetric survey and seismic array works carried out by the INGV research team in Sos Enattos and Bitti.