Number of the records: 1
Calculating flux to predict future cave radon concentrations
- 1.
SYSNO ASEP 0466615 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Calculating flux to predict future cave radon concentrations Author(s) Rowberry, Matthew David (USMH-B) RID, ORCID, SAI
Martí, Xavier (FZU-D) RID, ORCID
Frontera, C. (ES)
Van De Wiel, M.J. (GB)
Briestenský, Miloš (USMH-B) RID, ORCIDSource Title Journal of Environmental Radioactivity. - : Elsevier - ISSN 0265-931X
Roč. 157, JUN (2016), 16-26Number of pages 11 s. Publication form Print - P Language eng - English Country GB - United Kingdom Keywords cave radon concentration ; cave radon flux ; cave ventilation ; radioactive decay ; fault slip ; numerical modelling Subject RIV DC - Siesmology, Volcanology, Earth Structure Subject RIV - cooperation Institute of Physics - Nuclear, Atomic and Molecular Physics, Colliders R&D Projects LM2010008 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) Institutional support USMH-B - RVO:67985891 ; FZU-D - RVO:68378271 UT WOS 000375811700002 EID SCOPUS 84959421830 DOI https://doi.org/10.1016/j.jenvrad.2016.02.023 Annotation Cave radon concentration measurements reflect the outcome of a perpetual competition which pitches flux against ventilation and radioactive decay. The mass balance equations used to model changes in radon concentration through time routinely treat flux as a constant. This mathematical simplification is acceptable as a first order approximation despite the fact that it sidesteps an intrinsic geological problem: the majority of radon entering a cavity is exhaled as a result of advection along crustal discontinuities whose motions are inhomogeneous in both time and space. In this paper the dynamic nature of flux is investigated and the results are used to predict cave radon concentration for successive iterations. The first part of our numerical modelling procedure focuses on calculating cave air flow velocity while the second part isolates flux in a mass balance equation to simulate real time dependence among the variables. It is then possible to use this information to deliver an expression for computing cave radon concentration for successive iterations. The dynamic variables in the numerical model are represented by the outer temperature, the inner temperature, and the radon concentration while the static variables are represented by the radioactive decay constant and a range of parameters related to geometry of the cavity. Input data were recorded at Driny Cave in the Little Carpathians Mountains of western Slovakia. Here the cave passages have developed along splays of the NE-SW striking Smolenice Fault and a series of transverse faults striking NW-SE. Independent experimental observations of fault slip are provided by three permanently installed mechanical extensometers. Our numerical modelling has revealed four important flux anomalies between January 2010 and August 2011. Each of these flux anomalies was preceded by conspicuous fault slip anomalies. Workplace Institute of Rock Structure and Mechanics Contact Iva Švihálková, svihalkova@irsm.cas.cz, Tel.: 266 009 216 Year of Publishing 2017
Number of the records: 1