Uncertainty in Detection of Volcanic Activity Using Infrasound Arrays: Examples From Mt. Etna, Italy

Frontiers in Earth Science

David Fee¹  Matthew M. Haney²  John J. Lyons²  Aaron Wech²  Luciano Zuccarello³  Silvio De Angelis⁵  Alejandro Diaz-Moreno⁶ 

[1] Alaska Volcano Observatory, Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK, United States;Alaska Volcano Observatory, U.S. Geological Survey Volcano Science Center, Anchorage, AK, United States;Departamento de Fisica Teorica y del Cosmos, University of Granada, Granada, Spain;Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Pisa, Pisa, Italy;School of Environmental Sciences, University of Liverpool, Liverpool, United Kingdom;School of Geography, Politics and Sociology, Newcastle University, Newcastle upon Tyne, United Kingdom;

关键词: volcano infrasound;    infrasound arrays;    volcanic degassing;    ash explosions;    lava flow;    Mt. Etna;   

DOI  :  10.3389/feart.2020.00169

来源: DOAJ

【 摘 要 】

The injection of gas and pyroclastic material from volcanic vents into the atmosphere is a prolific source of acoustic waves. Infrasound arrays offer efficient, cost-effective, and near real-time solutions to track the rate and intensity of surface activity at volcanoes. Here, we present a simple framework for the analysis of acoustic array data, based on least-squares beamforming, that allows to evaluate the direction and speed of propagation of acoustic waves between source and array. The algorithms include a new and computationally efficient approach for quantitative assessment of the uncertainty on array measurements based on error propagation theory. We apply the algorithms to new data collected by two 6-element infrasound arrays deployed at Mt. Etna during the period July–August 2019. Our results demonstrate that the use of two infrasound arrays allowed detecting and tracking acoustic sources from multiple craters and active vents associated with degassing and ash-rich explosions, vigorous and frequent Strombolian activity, opening of new eruptive fractures and emplacement of lava flows. Finally, we discuss the potential use of metrics based on infrasound array analyses to inform eruption monitoring operations and early warning at volcanoes characterized by episodic intensification of activity.

【 授权许可】

Unknown