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High‐resolution radon monitoring and hydrodynamics at Mount Vesuvius
Author(s) -
Cigolini Corrado,
Salierno Francesco,
Gervino Gianpiero,
Bergese Paolo,
Marino Ciro,
Russo Massimo,
Prati Paolo,
Ariola Vincenzo,
Bonetti Roberto,
Begnini Stefania
Publication year - 2001
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2000gl012775
Subject(s) - radon , geology , caldera , volcano , seismology , basement , impact crater , geochemistry , geophysics , physics , civil engineering , quantum mechanics , astronomy , engineering
A yearlong high‐resolution radon survey has been carried on at Mount Vesuvius, starting in May 1998. Radon activities were acquired by exposing charcoal canisters and track‐etch detectors. Sampling stations were deployed along two major summit faults and around the caldera bottom. Volcanically‐related earthquakes, with M D ≥ 2.5, may be discriminated from regional seismic events since their cumulative radon anomalies are recorded from stations located along all the above structural features. On the contrary, radon anomalies correlated to regional earthquakes, with MD ≥ 4, are essentially recorded by the sampling sites located along the two summit faults (whose roots extend deeper into the Tertiary basement rocks that underlay the volcano). Radon migration to the surface is ruled by convection within a porous medium of relatively low porosity (ϕ ≈ 10 −5 ), suggesting that fluid motion is strongly localised along fractures. It is suggested that fluid pressure build up, followed by fluid release and migration during incipient fracturing of the porous medium, precede the onset of volcanically‐induced earthquakes.