Publication Date:
2021-12-23
Description:
Infrasonic signals investigation plays a fundamental role for both volcano monitoring
purpose and the study of the explosion dynamics. Proper and reliable detection of
weak signals is a critical issue in active volcano monitoring. In particular, in volcanic
acoustics, it has direct consequences in pinpointing the real number of generated events
(amplitude transients), especially when they exhibit low amplitude, are close in time to each
other, and/or multiple sources exist. To accomplish this task, several algorithms have been
proposed in literature; in particular, to overcome limitations of classical approaches such
as short-time average/long-time average and cross-correlation detector, in this paper a
subspace-based detection technique has been implemented. Results obtained by
applying subspace detector on real infrasound data highlight that this method allows
sensitive detection of lower energy events. This method is based on a projection of a sliding
window of signal buffer onto a signal subspace that spans a collection of reference signals,
representing similar waveforms from a particular infrasound source. A critical point is
related to subspace design. Here, an empirical procedure has been applied to build the
signal subspace from a set of reference waveforms (templates). In addition, in order to
determine detectors parameters, such as subspace dimension and detection threshold,
even in presence of overlapped noise such as infrasonic tremor, a statistical analysis of
noise has been carried out. Finally, the subspace detector reliability and performance, have
been assessed by performing a comparison among subspace approach, cross correlation detector and short-time average/long-time average detector. The obtained
confusion matrix and extrapolated performance indices have demonstrated the
potentiality, the advantages and drawbacks of the subspace method in tracking
volcanic activity producing infrasound events. This method revealed to be a good
compromise in detecting low-energy and very close in time events recorded during
Strombolian activity
Description:
Published
Description:
579923
Description:
5V. Processi eruttivi e post-eruttivi
Description:
JCR Journal
Keywords:
infrasound signal
;
trigger algorithm
;
infrasound volcano monitoring
;
strombolian activity
;
etna volcano
;
infrasonic tremor
;
subspace detector
;
infrasound events
;
solid earth
;
04.08. Volcanology
;
04.06. Seismology
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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