0000000000970228
AUTHOR
M. L. Carapezza
The Problem of Volcanic Unrest: The Campi Flegrei Case History
Campi Flegrei is one of the most densely populated active volcanic areas of the world. It consists of a complex structure with a multicollapse caldera and many postcaldera, explosive, mostly monogenetic vents. The last eruption was in 1538 (Mt. Nuovo). Progressive reduction of eruption energy has accompanied migration of the vents toward the center of the caldera. Campi Flegrei activity is fed by a shallow magma chamber in which trachybasaltic magma undergoes cooling and fractionation, producing trachytic residual melt that is periodically tapped and erupted to the surface. The depth of the chamber is estimated, from petrological and active and passive seismic data, to be about 4 km beneath…
New Insights into the Provenance of the Obsidian Fragments of the Island of Ustica (Palermo, Sicily)
In this study we applied a multidisciplinary approach, coupling geophysical and geochemical measurements, to unveil the provenance of 170 obsidian flakes, collected on the volcanic island of Ustica (Sicily). On this island there are some prehistoric settlements dated from the Neolithic to the Middle Bronze Age. Despite not having geological outcrops of obsidian rocks, the countryside of Ustica is rich in fragments of this volcanic glass, imported from other source areas. The study of obsidian findings was carried out first through visual observations and density measurements. At least two different obsidian families have been distinguished, probably imported from Lipari and Pantelleria isla…