More Like this

1. Volcano Opto‐Acoustics: Mapping the Infrasound Wavefield at Yasur Volcano (Vanuatu)

   https://doi.org/10.1029/2022GL102029  

   Johnson, J_B; Boyer, T.; Watson, L_M; Anderson, J_F (April 2023, Geophysical Research Letters)

   Abstract We explore the capabilities of volcano opto‐acoustics, a promising technique for measuring explosion and infrasound resonance phenomena at open‐vent volcanoes. Joint visual and infrasound study at Yasur Volcano (Vanuatu) demonstrate that even consumer‐grade cameras are capable of recording infrasound with high fidelity. Passage of infrasonic waves, ranging from as low as 5 Pa to hundreds of Pa, from both explosions and persistent tremor, pressurizes and depressurizes ambient plumes inducing visible vaporization and condensation respectively. Optical tracking of these pressure wavefields can be used to identify spectral characteristics, which vary within Yasur's two deep craters and are distinct for explosion and tremor sources. Wavefield maps can illuminate the propagation of blasts as well as the dynamics of persistent infrasonic tremor associated with standing waves in the craters. We propose that opto‐acoustic monitoring is useful for extraction of near‐vent infrasound signal and for tracking volcanic unrest from a remote distance. 

   more » « less
2. Volcanic ballistic projectile deposition from a continuously erupting volcano: Yasur Volcano, Vanuatu

   https://doi.org/10.30909/vol.03.02.183204  

   Fitzgerald, Rebecca Hanna; Kennedy, Ben M; Gomez, Christopher; Wilson, Thomas M; Simons, Benjamin; Leonard, Graham S; Matoza, Robin S; Jolly, Arthur D; Garaebiti, Esline (January 2020, Volcanica)

   null (Ed.)
3. Investigating Spectral Distortion of Local Volcano Infrasound by Nonlinear Propagation at Sakurajima Volcano, Japan

   https://doi.org/10.1029/2019JB018284  

   Maher, Sean P.; Matoza, Robin S.; de Groot‐Hedlin, Catherine D.; Gee, Kent L.; Fee, David; Yokoo, Akihiko (March 2020, Journal of Geophysical Research: Solid Earth)

   Abstract Sound waves generated by erupting volcanoes can be used to infer important source dynamics, yet acoustic source‐time functions may be distorted during propagation, even at local recording distances (15 km). The resulting uncertainty in source estimates can be reduced by improving constraints on propagation effects. We aim to quantify potential distortions caused by wave steepening during nonlinear propagation, with the aim of improving the accuracy of volcano‐acoustic source predictions. We hypothesize that wave steepening causes spectral energy transfer away from the dominant source frequency. To test this, we apply a previously developed single‐point, frequency domain, quadspectral density‐based nonlinearity indicator to 30 acoustic signals from Vulcanian explosion events at Sakurajima Volcano, Japan, in an 8‐day data set collected by five infrasound stations in 2013 with 2.3‐ to 6.2‐km range. We model these results with a 2‐D axisymmetric finite‐difference method that includes rigid topography, wind, and nonlinear propagation. Simulation results with flat ground indicate that wave steepening causes up to2 dB (1% of source level) of cumulative upward spectral energy transfer for Sakurajima amplitudes. Correction for nonlinear propagation may therefore provide a valuable second‐order improvement in accuracy for source parameter estimates. However, simulations with wind and topography introduce variations in the indicator spectra on order of a few decibels. Nonrandom phase relationships generated during propagation or at the source may be misinterpreted as nonlinear spectral energy transfer. The nonlinearity indicator is therefore best suited to small source‐receiver distances (e.g.,2 km) and volcanoes with simple sources (e.g., gas‐rich strombolian explosions) and topography. 

   more » « less
4. Reactivation of Cumbre Vieja volcano

   https://doi.org/10.1126/science.abm9423  

   Longpré, Marc-Antoine (December 2021, Science)

   After 50 years of repose, Cumbre Vieja volcano—historically the most active of the Canary Islands—entered an eruptive episode on 19 September 2021, forcing the evacuation of ∼6400 residents and destroying infrastructure worth more than 400 million euros. The volcanic unrest began in 2017 but accelerated only 8 days before the onset of the eruption. This behavior, characterized by comparatively protracted periods of quiescence and unrest, is at odds with global systematics for basaltic volcanoes ( 1 ). 

   more » « less
5. The use of volcano alert levels by the Alaska Volcano Observatory-current practices and challenges

   Coombs, M L; Cameron, C; Schneider, D J; Wech; A (December 2023, In AGU Fall Meeting Abstracts (Vol 2023, No 214, pp V33F-0214))