Publication Date:
2017-04-04
Description:
The chemical and isotopic compositions of the precipitation at Stromboli Island, Italy, were
investigated between October 2003 and October 2005. We employed a rain gauge network designed to
cover the range in exposures and elevations of the volcanic edifice. The hydrogen and oxygen isotopic
ratios vary greatly on a seasonal basis and correlate with air temperature. Deuterium excess values show a
positive correlation with altitude. No direct contribution of volcanogenic H or O is evident in the isotopic
composition of the rainwater. The chemical composition of the rainwater is principally controlled by the
sea aerosol contribution at the coastal sites, whereas it is significantly influenced by volcanic activity near
the summit vents. Interaction with volcanic acid gases is indicated by the pH, which is usually 1–2 units
lower near the craters than at the coastal sites. The S/Cl, Cl/F, and S/F molar ratios in rainwater 1.5 km
from the craters are consistent with those measured in the volcanic plume using other methods (diffusive
tubes and Fourier transform infrared spectroscopy). Rising of undegassed magmas changes these molar
ratios because of the differential degassing of sulphur, chlorine, and fluorine from the magma. We therefore
propose that the chemical composition of precipitation, within 1.5 km of the craters, provides additional
information that is useful for monitoring volcanic activity at Stromboli Island. Moreover, this paper
presents estimates of the fluxes of F, Cl, S, Na, K, Ca, and Mg to the soil that could be useful for
geochemical studies on groundwater.
Description:
Published
Description:
Q07006
Description:
JCR Journal
Description:
reserved
Keywords:
rainwater
;
isotopic composition
;
plume
;
volcanic gases
;
01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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