Article,
Analysis of multiple scattering at Vesuvius volcano, Italy, using data of the TomoVes active seismic experiment
Journal of Volcanology and Geothermal Research, 128 (1-3): 45--63 (Nov 15, 2003)
DOI: 10.1016/S0377-0273(03)00246-4
Abstract
Data from the TomoVes active seismic experiment are used to study
scattering effects in the shallow heterogeneous structure of Vesuvius
volcano. Seismograms from shots located on the volcano itself are
characterised by spindle-like envelopes, small or missing P-onsets,
missing S-onsets, and long codas. Seismograms from shots in the surroundings
of the volcano, on the contrary, show clear and impulsive P- and
S-onsets and short codas. The different shapes of the envelopes can
be explained by strong multiple scattering in the shallow heterogeneous
eruptive material of the volcano and single scattering in the surrounding
crust. The seismograms of shots located on the volcano are modeled
using the diffusion model with a diffusivity of d=0.1 km2/s for the
frequency range of 2-16 Hz. Assuming the dominance of S-waves in
the coda and a typical S-wave velocity of around 1.5 km/s, this corresponds
to a transport mean free path ltr of only 200 m which is 3 orders
of magnitude smaller than for normal Earth crust. These results show
that multiple scattering is an important effect which cannot be neglected
in the modeling of seismic wave propagation in volcanic environments.
