Publication Date:
2021-11-26
Description:
We present the first two-dimensional (2-D) spatial distribution of seismic scattering and
intrinsic attenuation beneath the Aeolian Islands arc. The Aeolian Islands archipelago
represents one of the best examples of a small dimension volcanic island arc characterised
by the alternation of different structural domains. Using the seismic wave diffusion model as
the basis for the analysis, and using data from an active seismic experiment (TOMO-ETNA),
we analysed more than 76,700 seismic paths marked by epicentre-seismic station pairs.
Based on frequencies of 4–24 Hz, we identified high regional attenuation, comparable with
other volcanic areas of the world. We used two different seismogram lengths, reflecting
two different sampling depths, which allowed us to observe two different attenuative
behaviours. As in most volcanic regions, scattering attenuation predominates over intrinsic
attenuation, but some characteristics are area-specific. Volcanic structures present the
highest contribution to scattering, especially in the low frequency range. This behaviour is
interpreted to reflect the small size of the islands and the potentially relatively small size of
individual magmatic feeding systems. In addition, strong scattering observed in one zone is
associated with the northernmost part of the so-called Aeolian-Tindari-Letojanni fault
system. In contrast, away from the volcanic islands, intrinsic attenuation dominates over
scattering attenuation. We interpret this shift in attenuative behaviour as reflecting the large
volume of sedimentary material deposited on the seabed. Owing to their poorly
consolidated nature, sediments facilitate intrinsic attenuation via energy dissipation, but
in general present high structural homogeneity that is reflected by low levels of scattering.
Our results show that this region is not underlain by a large volcanic structural complex
such as that beneath nearby Mt. Etna volcano. Instead, we observe dimensionally smaller
and isolated subsurface volcanic structures. The identification of such features facilitates
improved geological interpretation; we can now separate consolidated marine structures
from independent subsurface volcanic elements. The results of this study provide a model
for new research in similar regions around the world.
Description:
Published
Description:
725402
Description:
2V. Struttura e sistema di alimentazione dei vulcani
Description:
JCR Journal
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
Permalink