Publication Date:
2020-04-09
Description:
This work is devoted to the study of both earthquakes and background seismic noise at Ischia Island (Italy) recorded pre and post the Md 4.0 earthquake occurred on 21 August 2017 (18:57 UTC). We compare and characterize noise and earthquakes in terms of Independent Component Analysis, energy and polarization properties. The earthquakes’ waveforms and the background noise are decomposed into a few independent components with two main common signals peaked around 1–2 and 3–4 Hz, respectively. A slight increase of the energy of the background seismic noise is observed comparing samples recorded in 2016 and 2017, whereas no variations are detected in 2017 pre and post the main earthquake. The polarization analysis, performed in the frequency bands individuated by Independent Component Analysis and applied to the background seismic noise, indicates a shallow propagation and the azimuthal pattern is mainly controlled by the local structural features. These results suggest that noise and earthquakes are ascribable to a common phenomenon of fluid-solid interaction in the hydrothermal system of Ischia Island.
Description:
Published
Description:
19-28
Description:
3T. Sorgente sismica
Description:
4V. Processi pre-eruttivi
Description:
JCR Journal
Keywords:
Ischia volcano
;
Source dynamics
;
Data analysis
;
04.08. Volcanology
;
04.06. Seismology
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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