Volume Flow Rate Estimation for Small Explosions at Mt. Etna, Italy, From Acoustic Waveform Inversion. Issue 20 (28th October 2019)

• Record Type: Journal Article
• Authors: Diaz‐Moreno, A.; Iezzi, A. M.; Lamb, O. D.; Fee, D.; Kim, K.; Zuccarello, L.; De Angelis, S.
• Is Part Of: Geophysical research letters. Volume 46:Issue 20(2019)
• Page Start: 11071
• Page End: 11079
• Publication Date: 2019-10-28
• Subjects: volcano infrasound -- Mt. Etna -- waveform inversion -- FDTD -- volume flow rate -- eruption intensity; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2019GL084598
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Rapid assessment of the volume and the rate at which gas and pyroclasts are injected into the atmosphere during volcanic explosions is key to effective eruption hazard mitigation. Here, we use data from a dense infrasound network deployed in 2017 on Mt. Etna, Italy, to estimate eruptive volume flow rates (VFRs) during small gas‐and‐ash explosions. We use a finite‐difference time‐domain approximation to compute the acoustic Green's functions and perform a full waveform inversion for a multipole source, combining monopole and horizontal dipole terms. The inversion produces realistic estimates of VFR, on the order of 4 × 10 4 m 3 /s and well‐defined patterns of source directivity. This is the first application of acoustic waveform inversion at Mt. Etna. Our results demonstrate that acoustic waveform inversion is a mature and robust tool for assessment of source parameters and holds potential as a tool to provide rapid estimates of VFR in near real time. Plain Language Summary: Rapid and realistic assessment of the volume of erupted material, and the rate at which gas and pyroclasts are injected into the atmosphere during volcanic explosions, is crucial for effective monitoring and hazard mitigation. These parameters, for instance, are key inputs into models of atmospheric rise and transport of volcanic plumes. Volcanic explosions, among many other phenomena, generate atmospheric pressure waves known as infrasound. These sound waves that propagate at frequencies below 20 Hz, represent a powerful tool to investigate the dynamics and source mechanisms of volcanic explosions. Here, we demonstrate how recordings of acoustic infrasound generated by explosions at Mt. Etna can be used to assess the volume flow history of these events. We introduce and apply a data modeling workflow that could be implemented in near real time at Mt. Etna and other volcanoes worldwide. Key Points: This is the first application of acoustic waveform inversion for small explosions at Mt. Etna volcano, Italy We demonstrate the feasibility of applying this inversion method for large volcanoes using up to 14 stations Acoustic waveform inversion holds potential for volume flow estimation in near real time at Mt. Etna and other volcanoes