First 2-D intrinsic and scattering attenuation images of Mt Etna volcano and surrounding region from active seismic data

Abstract

SUMMARYWe present 2-D attenuation images of the Mt Etna volcanic region on the basis of separation of intrinsic and scattering effects. The analysis presented here exploits a large active seismic database that fully covers the area under study. We observe that scattering effects dominate over intrinsic attenuation, suggesting that the region is very heterogeneous. Comparison with analyses conducted at other volcanoes reveals that the Mt Etna region is characterized by high intrinsic attenuation, resulting from the presence of large volcanoclastic deposits at shallow depth. The 2-D distributions of intrinsic and scattering anomalies show the presence of regions characterized by high and low attenuation effects, corresponding to several tectonic and volcanic features. In particular, we identify a high attenuation region in the SW sector of the Mt Etna volcanic complex, which is correlated with high seismicity rates and volcanism. This work supports the hypothesis of a link between the dynamics of the SW flank and the recharge of the volcano in the last decades, occurring under the summit crater and, secondarily, the upper South rift zone.