Abstract

In this article, we analyze the seismic wavefield produced by blasts fired at Mt. Vesuvius for a deep seismic sounding experiment and recorded by a dense short-period three-component seismic array. Seismograms from five explosions occurring at the bottom of wells located at different distances and azimuth with respect to the array site have been analyzed with the zero lag cross-correlation technique applied to both vertical and horizontal components in the frequency range 3–7 Hz. The aim is to analyze the portion of the seismograms long after the first P onset in order to obtain the slowness and backazimuth distribution of correlated secondary phases. Polarization analysis in time domain, carried out using the array covariance matrix technique, has also been applied to the well-correlated phases to determine their wave composition. Results show that the correlated phases detected in the coda of the seismogram shots are composed almost entirely of surface waves. Location of the scatterers shows a high concentration of the scatterers in and around the volcanic edifice of Mt. Vesuvius, confirming that topographical irregularities play an important role in the generation of the high-frequency scattering phenomena.

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