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Continuous gravity recordings at Campi Flegrei caldera by means of spring and superconducting gravimeters

Raffaella Casolaro1, Umberto Riccardi1 , Tommaso Pivetta2 , Jacques Hinderer3 , Frederic Littel3, Alessandro Fedele2, Giuseppe Ricciardi2, Stefano Carlino2

  • Affiliations: 1 Dipartimento di Scienze della Terra, dell'Ambiente e delle Risorse, Universita` di Napoli Federico II, Naples, Italy. 2 Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Napoli--Osservatorio Vesuviano, Naples, Italy. 3 Institut Terre et Environnement de Strasbourg (UMR 7063), Université de Strasbourg/EOST, CNRS, Strasbourg, France.

  • Presentation type: Poster

  • Presentation time: Friday 16:30 - 18:00, Room Poster Hall

  • Poster Board Number: 207

  • Programme No: 3.10.10

  • Theme 3 > Session 10

Abstract

We present the results of continuous gravity recordings collected at Campi Flegrei caldera (CFc). CFc is an active volcano in southern Italy, currently in a state of unrest characterised by ground deformation, seismic activity and fumarolic emissions. Since the 80's, periodic six-month time-lapse gravity surveys are carried out on a network of benchmarks for volcano monitoring. Due to the intensification of the unrest, in January 2023, a permanent gravity station, equipped with a gPhoneX spring gravimeter, was installed to complement the relative gravity surveys, allowing an improved temporal resolution. Thereafter, in October 2024, through a collaboration between INGV, DiSTAR and Institut Terre et Environnement de Strasbourg (ITES), a superconducting gravimeter (iGrav#029) was provided on loan and installed at Rione Terra, the most active sector of CFc, where the largest ground deformations occur. We report on processing and analyses performed to obtain reliable parameters for Earth and oceanic tides, non-tidal corrections, and gravity residuals for both gravimeters. Concerning the gPhoneX, due to the large instrumental drift, the latter was carefully analyzed, as it can hide elusive long-term gravity changes eventually caused by underground mass variations. For the iGrav#029, the focus was on the accurate calibration. It was carried out through multiple approaches, including synthetic tides, parallel measurements with an A10 absolute gravimeter and the gPhoneX. Always in view of catching elusive volcanic gravity signals, we examine in depth the relationship between gravity and atmospheric pressure changes both in time and frequency domain. Gravity signals are interpreted in light of the current dynamics at CFc.