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| Titel |
Automatic procedure for quasi-real time seismic data processing at Campi Flegrei (Italy) |
| VerfasserIn |
Paolo Capuano, Angelo Ciaramella, Enza De Lauro, Salvatore De Martino, Mariarosaria Falanga, Simona Petrosino |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250094456
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| Publikation (Nr.) |
 EGU/EGU2014-9864.pdf |
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| Zusammenfassung |
| The accuracy of automatic procedures for detecting seismic events and locating their
sources is influenced by several factors such as errors in picking seismic phases often
buried in the high-level ambient noise, network geometry and modelling errors.
fundamental objective is the improvement of these procedures by developing accurate
algorithms for quasi-real time seismic data processing, easily managed in observatory
practice.
Recently a robust automatic procedure has been implemented for detecting, onset picking
and identifying signal phases in continuous seismic signal with an application at the
seismicity recorded at Campi Flegrei Caldera (Italy) during the 2006 ground uplift
(Ciaramella et al. 2011). An Independent Component Analysis based approach for the Blind
Source Separation of convolutive mixtures (CICA) has been adopted to obtain a clear
separation of low-energy Long Period events (LPs) from the high-level ambient noise
allowing to compile a complete seismic catalogue and better quantify the seismic energy
release. In this work, we apply CICA at the seismic signal continuously recorded during the
entire 2006 at Campi Flegrei. First, we have performed tests on synthetic data in order to
improve the reliability and the accuracy of the procedure. The performance test
using very noisy synthetic data shows that the method works even in case of very
poor quality data characterized by very low signal to noise ratio (SNR). Second,
we have improved CICA automatic procedure recovering the information on the
amplitudes of the extracted independent components. This is crucial for further
analysis, starting from a prompt estimate of magnitude/energy of the highlighted
events.
Data used for the present analysis were collected by four broadband three-component
seismic stations (ASB2, AMS2, TAGG, BGNG) belonging to the Campi Flegrei
seismic monitoring network, managed by the “Istituto Nazionale di Geofisica e
Vulcanologia-Osservatorio Vesuviano (INGV-OV)” (see for details Saccorotti et al. [2007]).
Specifically, the analyzed time series are the recordings of ground velocity (seismograms)
along the three directions of motion (North–South, East–West and Vertical) for each station.
We focus the attention not only on the detection of LPs, but also on volcano–tectonic quakes
and on the study of the noise itself, including its separation into meteomarine, anthropogenic
and volcanic (tremor) sources. The extracted waveforms with improved SNR via CICA
coupled with automatic phase picking (based on the comparison of short-term average
amplitude and long-term average) allow to obtain precise polarization analysis and
localizations. |
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