Water 2018, 10(9), 1276; https://doi.org/10.3390/w10091276
Diurnal and Semidiurnal Cyclicity of Radon (222Rn) in Groundwater, Giardino Spring, Central Apennines, Italy
1
Dipartimento di Scienze della Terra, Sapienza Università di Roma, P.le Aldo Moro 5, 00185 Roma, Italy
2
Consiglio Nazionale delle Ricerche, IGAG, c.o. Dipartimento di Scienze della Terra, Sapienza Università di Roma, P.le Aldo Moro 5, 00185 Roma, Italy
3
Istituto Nazionale di Geofisica e Vulcanologia, sede di Roma, Via di Vigna Murata 605, 00143 Roma, Italy
4
Dipartimento di Ingegneria e Geologia, Università G. d’Annunzio Chieti-Pescara, 66100 Chieti, Italy
*
Author to whom correspondence should be addressed.
Received: 30 July 2018 / Revised: 4 September 2018 / Accepted: 13 September 2018 / Published: 18 September 2018
(This article belongs to the Special Issue Isotopes in Hydrology and Hydrogeology)
Abstract
Understanding natural variations of Rn (222Rn) concentrations is the fundamental prerequisite of using this radioactive gas as a tracer, or even precursor, of natural processes, including earthquakes. In this work, Rn concentrations in groundwater were continuously measured over a seven-month period, during 2017, in the Giardino Spring, Italy, together with groundwater levels in a nearby well installed into a fractured regional aquifer. Data were processed to reduce noise, and then analyzed to produce the Fourier spectra of Rn concentrations and groundwater levels. These spectra were compared with the spectrum of tidal forces. Results showed that diurnal and semidiurnal cycles of Rn concentrations, and filtered oscillations of groundwater levels, in the nearby well, are correlated with solar and luni-solar components of tidal forces, and suggested no correlation with the principal lunar components. Therefore, influencing factors linked to solar cycles, such as daily oscillations of temperature and atmospheric pressure, and related rock deformations, may have played a role in Rn concentrations and groundwater levels. An open question remains regarding the correlation, which is documented elsewhere, of Rn concentrations and groundwater levels with the lunar components of the solid Earth tides. View Full-TextKeywords:
radon concentration; groundwater; water table; Earth tide; central Apennines
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Barberio, M.D.; Gori, F.; Barbieri, M.; Billi, A.; Devoti, R.; Doglioni, C.; Petitta, M.; Riguzzi, F.; Rusi, S. Diurnal and Semidiurnal Cyclicity of Radon (222Rn) in Groundwater, Giardino Spring, Central Apennines, Italy. Water 2018, 10, 1276.
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