Forecasting the eruption of an open-vent volcano using resonant infrasound
            tones

Johnson, J. B.; Watson, Leighton M.; Palma, José Luis; Dunham, Eric M.; Anderson, J.

doi:10.18122/b21b0c

Cited by 13 publications

(27 citation statements)

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“…Following subsidence of the lava lake out of view in June 2012, the emission rate reduced to an average of 386 t/day until February 2015 (OVDAS, personal communication). Prior to the paroxysmal eruption of 3 March 2015, volcanic infrasound signals recorded a rapid increase in the level of the magma free surface from a stable level at >120 m below the crater rim to <70 m in the days prior to the eruption (Johnson et al, ). Following the eruption, the lake level remained high, maintaining an average SO 2 flux of 714 t/day until December 2017 when the magma column again withdrew out of sight (OVDAS, personal communication).…”

Section: Geological Settingmentioning

confidence: 99%

Dynamics of Outgassing and Plume Transport Revealed by Proximal Unmanned Aerial System (UAS) Measurements at Volcán Villarrica, Chile

Liu

Wood

Mason

et al. 2019

Geochem Geophys Geosyst

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Volcanic gas emissions are intimately linked to the dynamics of magma ascent and outgassing and, on geological time scales, constitute an important source of volatiles to the Earth's atmosphere. Measurements of gas composition and flux are therefore critical to both volcano monitoring and to determining the contribution of volcanoes to global geochemical cycles. However, significant gaps remain in our global inventories of volcanic emissions, (particularly for CO 2 , which requires proximal sampling of a concentrated plume) for those volcanoes where the near-vent region is hazardous or inaccessible. Unmanned Aerial Systems (UAS) provide a robust and effective solution to proximal sampling of dense volcanic plumes in extreme volcanic environments. Here we present gas compositional data acquired using a gas sensor payload aboard a UAS flown at Volcán Villarrica, Chile. We compare UAS-derived gas time series to simultaneous crater rim multi-GAS data and UV camera imagery to investigate early plume evolution. SO 2 concentrations measured in the young proximal plume exhibit periodic variations that are well correlated with the concentrations of other species. By combining molar gas ratios (CO 2 /SO 2 = 1.48-1.68, H 2 O/SO 2 = 67-75, and H 2 O/CO 2 = 45-51) with the SO 2 flux (142 ± 17 t/day) from UV camera images, we derive CO 2 and H 2 O fluxes of~150 t/day and~2,850 t/day, respectively. We observe good agreement between time-averaged molar gas ratios obtained from simultaneous UAS-and ground-based multi-GAS acquisitions. However, the UAS measurements made in the young, less diluted plume reveal additional short-term periodic structure that reflects active degassing through discrete, audible gas exhalations.

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Section: Geological Settingmentioning

confidence: 99%

Dynamics of Outgassing and Plume Transport Revealed by Proximal Unmanned Aerial System (UAS) Measurements at Volcán Villarrica, Chile

Liu

Wood

Mason

et al. 2019

Geochem Geophys Geosyst

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“…In [8] it was demonstrated how infrasound can be used to track the surface of the lava lake in the crater of Volcán Villarrica (Chile). The position of the lava lake may in turn be used to forecast volcanic eruptions.…”

Section: Resonant Infrasound Tones Of Volcán Villarricamentioning

confidence: 99%

“…The nearest infrasound station is located about 4 km northwest of the crater. To obtain a relevant crater topography we use a two-dimensional average of the three-dimensional crater geometry in [8], see x ∈ [−173 m, 173 m] in Figure 8b. The conduit, centered at x = 0 m, is approximated to have perfectly vertical sides.…”

Section: Resonant Infrasound Tones Of Volcán Villarricamentioning

confidence: 99%

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Non-stiff boundary and interface penalties for narrow-stencil finite difference approximations of the Laplacian on curvilinear multiblock grids

Almquist

Dunham

2020

Journal of Computational Physics

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The Laplacian appears in several partial differential equations used to model wave propagation. Summation-by-parts-simultaneous approximation term (SBP-SAT) finite difference methods are often used for such equations, as they combine computational efficiency with provable stability on curvilinear multiblock grids. However, the existing SBP-SAT discretization of the Laplacian quickly becomes prohibitively stiff as grid skewness increases. The stiffness stems from the SATs that impose inter-block couplings and Dirichlet boundary conditions. We resolve this issue by deriving stable SATs whose stiffness is almost insensitive to grid skewness. The new discretization thus allows for large time steps in explicit time integrators, even on very skewed grids. It also applies to the variable-coefficient generalization of the Laplacian. We demonstrate the efficacy and versatility of the new method by applying it to acoustic wave propagation problems inspired by marine seismic exploration and infrasound monitoring of volcanoes.

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“…The frequency of the tremor shows a monochromatic nature, with a significant peak occurring at a low frequency. The source mechanisms of the tremor have been proposed to be the resonance of the topographic cavity above the lava lake (Fee et al 2010), the resonance of the air column at the uppermost end of the conduit (Goto and Johnson 2011;Johnson et al 2018a;Spina et al 2015), or the resonance of the ash-gas column above the fragmentation front in the conduit during ash-gas ejection (Yokoo et al 2008). Another potential source of such infrasound signals was also proposed to be the direct relation of the flow dynamics of gas bubbles during their ascent in the magma column (Ripepe et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Monochromatic infrasound waves observed during the 2014–2015 eruption of Aso volcano, Japan

Yokoo

Ishii

Ohkura

et al. 2019

Earth Planets Space

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Monochromatic infrasound waves are scarcely reported volcanic infrasound signals. These waves have the potential to provide constraints on the conduit geometry of a volcano. However, to further investigate the waves scientifically, such as how the conduit shape modulates the waveforms, we still need to examine many more examples. In this paper, we provide the most detailed descriptions of these monochromatic infrasound waves observed at Aso volcano in Japan. At Aso volcano, a 160-day-long magmatic eruption occurred in 2014-2015 after a 20-year quiescent period. This eruption was the first event that we could monitor well using our infrasound network deployed around the crater. Throughout the entire eruption period, when both ash venting and Strombolian explosions occurred, monochromatic infrasound waves were observed nearly every day. Although the peak frequency of the signals (0.4-0.7 Hz) changed over time, the frequency exhibited no reasonable correlation with the eruption style. The source location of the signals estimated by considering topographic effects and atmospheric conditions was highly stable at the active vent. Based on the findings, we speculate that these signals were related to the resonant frequencies of an open space in the conduit: the uppermost part inside the vent. Based on finite-difference time-domain modeling using 3-D topographic data of the crater during the eruption (March 2015), we calculated the propagation of infrasound waves from the conduit. Assuming that the shape of the conduit was a simple pipe, the peak frequency of the observed waveforms was well reproduced by the calculation. The length of the pipe markedly defined the peak frequency. By replicating the observed waveform, we concluded that the gas exhalation with a gas velocity of 18 m/s occurred at 120 m depth in the conduit. However, further analysis from a different perspective, such as an analysis of the time difference between the arrivals of infrasound and seismic waves, is required to more accurately determine the conduit parameters based on observational data.

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Forecasting the eruption of an open-vent volcano using resonant infrasound tones

Cited by 13 publications

References 0 publications

Dynamics of Outgassing and Plume Transport Revealed by Proximal Unmanned Aerial System (UAS) Measurements at Volcán Villarrica, Chile

Dynamics of Outgassing and Plume Transport Revealed by Proximal Unmanned Aerial System (UAS) Measurements at Volcán Villarrica, Chile

Non-stiff boundary and interface penalties for narrow-stencil finite difference approximations of the Laplacian on curvilinear multiblock grids

Monochromatic infrasound waves observed during the 2014–2015 eruption of Aso volcano, Japan

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