Wideband acoustic records of explosive volcanic eruptions at Stromboli: New insights on the explosive process and the acoustic source

Akio Goto, M. Ripepe, G. Lacanna

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

Wideband acoustic waves, both inaudible infrasound (<20 Hz) and audible component (>20 Hz), generated by strombolian eruptions were recorded at 5 kHz and correlated with video images. The high sample rate revealed that in addition to the known initial infrasound, the acoustic signal includes an energetic high-frequency (typically >100 Hz) coda. This audible signal starts before the positive infrasound onset goes negative. We suggest that the infrasonic onset is due to magma doming at the free surface, whereas the immediate high-frequency signal reflects the following explosive discharge flow. During strong gas-rich eruptions, positively skewed shockwave-like components with sharp compression and gradual depression appeared. We suggest that successive bursting of overpressurized small bubbles and the resultant volcanic jets sustain the highly gas-rich explosions and emit the audible sound. When the jet is supersonic, microexplosions of ambient air entrained in the hot jet emit the skewed waveforms.

Original languageEnglish
Pages (from-to)3851-3857
Number of pages7
JournalGeophysical Research Letters
Volume41
Issue number11
DOIs
Publication statusPublished - 2014 Jan 1

Keywords

  • Stromboli volcano
  • audible acoustic wave
  • crackle
  • infrasound
  • supersonic jet

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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