GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 2.1 GNGTS 2024 Imprints of the Earth's gravity on recent seismic events in Ceneselli, Italy M. Campion 1 , C. Fidani 2,3 ​ 1 Gruppo Astrofili Polesani, Rovigo, Italy ​ 2 Istituto Nazionale di Geofisica e Vulcanologia, Roma, Italy ​ 3 Cenrtral Italy Electromagnetic Network, Fermo, Italy A laborious mechanical manufacture for the realization of a gravimeter was initiated at the beginning of 2000. The instrument manufacturer, Mario Giorgio Campion, put the gravimeter into operation at his home in via Arturo Toscanini 27 in Rovigo, Italy. The gravimeter is made up of a highly precise pendulum with damped oscillations: an integral accelerometer, which is able to detect oscillation times with precision and continuity (Campion, 2022). It was realized using materials and construction techniques to obtain the maximum rigour in the measurement of the variable (see Figure 1): - it works under vacuum; - with thermostatation; - use rods in quartz and/or invar steel; - synchronism with the focused laser; - signals go throungh an optical fiber; - times measured with a Rubidium clock; - a computer controls and records data. With these solutions, the variations of the period with respect to temperature were verified to be of the order of 1.65 μsec/°C. Through approximately 500 daily measurements, the instrument is able to measure local relative gravity continuously, over very narrow time intervals of approximately three minutes. Starting from 2000, the relative gravity recording went on for at least a decade; alternating intervals of stops of the gravimeter. The maintenance periods were useful in order to make necessary improvements to the system, therein reducing errors in the measurements both of random and systematic nature. This period was also useful to better understand the character of the captured data regarding the fundamental quantity of the gravity dependent on the mass of the Earth. Moreover, gravity is influenced by the nature of the subsoil, as well as by the geographical position of the location, and the altitude of the ground.