Article,
Seismic structure beneath Mt Vesuvius from receiver function analysis and local earthquakes tomography: evidences for location and geometry of the magma chamber
Geophysical Journal International, 175 (3): 1298--1308 (December 2008)
DOI: 10.1111/j.1365-246X.2008.03868.x
Abstract
The recognition and localization of magmatic fluids are pre-requisites
for evaluating the volcano hazard of the highly urbanized area of
Mt Vesuvius. Here we show evidence and constraints for the volumetric
estimation of magmatic fluids underneath this sleeping volcano. We
use Receiver Functions for teleseismic data recorded at a temporary
broad-band station installed on the volcano to constrain the S-wave
velocity structure in the crust. Receiver Functions are analysed
and inverted using the Neighbourhood Algorithm approach. The 1-D
S-velocity profile is jointly interpreted and discussed with a new
Vp and Vp/Vs image obtained by applying double difference tomographic
techniques to local earthquakes. Seismologic data define the geometry
of an axial, cylindrical high Vp, high Vs body consisting of a shallow
solidified materials, probably the remnants of the caldera, and ultramafic
rocks paving the crustal magma chamber. Between these two anomalies,
we find a small region where the shear wave velocity drops, revealing
the presence of magma at relatively shallow depths. The volume of
fluids (30 km3) is sufficient to contribute future explosive eruptions.
