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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Earth Sci. | doi: 10.3389/feart.2019.00307

Insight into the wave scattering properties of the Solfatara Volcano.

 Antonio Scala1, Marcello Serra1,  Gaetano Festa1* and Philippe Roux2
  • 1University of Naples Federico II, Italy
  • 2Université Grenoble Alpes, France

In this study we inferred statistical properties related to the scatterers within a volcanic area, the Solfatara crater, located in the Campi Flegrei caldera, Southern Italy. We analyzed active seismic data recorded in a 3D geometry during the first RICEN experiment, held in September 2013. After extraction of seismic sections, we evaluated the coherent and incoherent intensities, averaging over sources and receivers sharing the same source-station distance. We thus computed the ratio between the two intensities over the surface waves, which is almost sensitive to the scattering mean free path in the area. We found that the intensity ratio exponentially decreases with distance, while the final plateau can be recognized only if the average is performed moving sources and receivers over the whole domain of investigation.
We report that the scattering mean free path exhibits a small increase between 7.5 Hz and 10 Hz from 50 m to 60 m, and then it decreases down to about 10 m, at a frequency of 21.5 Hz.
Since the scattering mean free path can be determined assuming a constant Rayleigh group velocity of 65 m/s, we modelled it as generated by a single scatterer of cylindrical shape in a homogeneous medium. We found that the average size of the scatterer is about 10 m, with a small increase of the Rayleigh wave velocity inside the scatterer.
The scatterers are here interpreted as regions richer in water with respect to the background and eventually due to the condensed steam running below the investigated area.

Keywords: Volcano Seismology, scattering, surface wave (SW), Mean free path (MFP), Campi Flegrei (southern Italy) volcanic area, wave attenuation

Received: 26 Jul 2019; Accepted: 04 Nov 2019.

Copyright: © 2019 Scala, Serra, Festa and Roux. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Prof. Gaetano Festa, University of Naples Federico II, Naples, 80138, Campania, Italy, gaetano.festa@unina.it