title: Natural gamma-radiation in the Aeolian volcanic arc.
abstract: Pulse-height distributions of gamma-rays, obtained with a field NaI(Tl) scintillation spectrometer in numerous sites of the Lipari and Vulcano islands (Aeolian volcanic arc, Italy), were measured to determine the U, Th and K concentrations of the bedrock and the relative values of the air absorbed dose rate. U is spatially related to both Th and K and the Th/U ratio is on average 3.1-3.5. The magmatic evolution is reflected by the concentration of the three radioelements, as they are more abundant within the more felsic units of the volcanic series. The higher values of U (15.7-20.0 ppm) coincide with higher Th (48.3-65.9 ppm) and K (4.9-6.1%) concentrations associated with rhyolitic rocks of the third cycle (< 50 ky). The air absorbed dose rate varies from 20 to 470 nGy h(-1). The highest values (> 350 nGy h(-1)) are observed on outcrops of rhyolitic obsidian lava flows. The cosmic-ray contribution is also evaluated to estimate the total background radiation dose rate.
authors.affiliation: Dipartimento Studio Territorio e Risorse, Settore di Geofisica, Università di Genova, Genoa, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Chiozzi
authors.forename: V
authors.initials: V
authors.lastname: Pasquale
authors.forename: M
authors.initials: M
authors.lastname: Verdoya
authors.forename: S
authors.initials: S
authors.lastname: Minato