Thermal-image-derived dynamics of vertical ash plumes at Santiaguito volcano, Guatemala

Sahetapy-Engel, Steve T.; Harris, Andrew

doi:10.1007/s00445-009-0284-8

Cited by 28 publications

(33 citation statements)

References 16 publications

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“…The high air entrainment recorded here is no doubt a result of emission from a circular vent structure (Bluth and Rose, 2004;Sahetapy-Engel and Harris, 2009a). Both studies record main ash emission being from sources located around the edge of the roughly circular vent located atop the Caliente dome.…”

Section: Discussionmentioning

confidence: 83%

“…(14) with the analytical solution of Eq. (23), with the vent conditions for the plume at Santiaguito (Sahetapy-Engel and Harris, 2009a;Valade et al, 2014) obtained in Section 5 ( Table 2). Consistent with this approximation, the analytical solution closely fits the complete model solution in the central part of the plume.…”

Section: Approximate Solution Of the Plume Modelmentioning

confidence: 96%

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Volcanic plume vent conditions retrieved from infrared images: A forward and inverse modeling approach

Cerminara

Ongaro

Valade

et al. 2015

Journal of Volcanology and Geothermal Research

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International audienceWe present a coupled fluid-dynamic and electromagnetic model for volcanic ash plumes. In a forward approach, the model is able to simulate the plume dynamics from prescribed input flow conditions and generate the corresponding synthetic thermal infrared (TIR) image, allowing a comparison with field-based observations. An inversion procedure is then developed to retrieve vent conditions from TIR images, and to independently estimate the mass eruption rate.The adopted fluid-dynamic model is based on a one-dimensional, stationary description of a self-similar turbulent plume, for which an asymptotic analytical solution is obtained. The electromagnetic emission/absorption model is based on Schwarzschild's equation and on Mie's theory for disperse particles, and we assume that particles are coarser than the radiation wavelength (about 10 μm) and that scattering is negligible. In the inversion procedure, model parameter space is sampled to find the optimal set of input conditions which minimizes the difference between the experimental and the synthetic image.Application of the inversion procedure to an ash plume at Santiaguito (Santa Maria volcano, Guatemala) has allowed us to retrieve the main plume input parameters, namely mass flow rate, initial radius, velocity, temperature, gas mass ratio, entrainment coefficient and their related uncertainty. Moreover, by coupling with the electromagnetic model we have been able to obtain a reliable estimate of the equivalent Sauter diameter of the total particle size distribution.The presented method is general and, in principle, can be applied to the spatial distribution of particle concentration and temperature obtained by any fluid-dynamic model, either integral or multidimensional, stationary or time-dependent, single or multiphase. The method discussed here is fast and robust, thus indicating potential for applications to real-time estimation of ash mass flux and particle size distribution, which is crucial for model-based forecasts of the volcanic ash dispersal process

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Section: Discussionmentioning

confidence: 83%

Section: Approximate Solution Of the Plume Modelmentioning

confidence: 96%

Volcanic plume vent conditions retrieved from infrared images: A forward and inverse modeling approach

Cerminara

Ongaro

Valade

et al. 2015

Journal of Volcanology and Geothermal Research

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“…The lowest portion is the gas-thrust region, and comprises the lava fountains (Sparks et al, 1997;Bonaccorso and Calvari, 2017). Measured ascent velocities in this region are normally greater than 15 m s −1 (Patrick, 2007;Patrick et al, 2007;Sahetapy-Engel and Harris, 2009), and for Etna vary between 33 and 125 m s −1 Carbone et al, 2015;Giuffrida et al, 2018), but values of 170, 227, and 405 m s −1 have been measured at Montserrat, Sakurajima, and Stromboli volcanoes, respectively (Clarke et al, 2002;Taddeucci et al, 2012;Tournigand et al, 2017). Above the gas-thrust is the convective region, where atmospheric mixing occurs (Sparks et al, 1997;Bombrun et al, 2018), causing a decrease in ascent velocity and lateral wind transport (Carey and Sparks, 1986).…”

Section: Introductionmentioning

confidence: 99%

Paroxysmal Explosions, Lava Fountains and Ash Plumes at Etna Volcano: Eruptive Processes and Hazard Implications

et al. 2018

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Lava fountains have a major impact on the local population since they cause ash plumes that spread several kilometers above and hundreds of kilometers away from the crater. Ash fallout is responsible for disrupting airports and traffic on the motorways well beyond the area of the volcano itself, as well as affecting the stability of buildings and causing public health issues. It is thus a primary scientific target to forecast the impact of this activity on local communities on the basis of parameters recorded by the monitoring network. Between 2011 and 2015, 49 paroxysmal explosive episodes occurred at two of Mt Etna's five summit craters: the New South-East Crater (NSEC) and the Voragine (VOR). In this paper, we examine the features of the 40 episodes occurring at the NSEC during 2011-2013, and of the 4 events at VOR in December 2015. We study these paroxysms using geophysical monitoring data, characterize the episodes, and analyse all available data statistically. Our main results are two empirical relationships allowing us to forecast the maximum elevation of the ash plume from the average height of the lava fountain, useful for hazard assessment and risk mitigation. For Etna, and using the examples described in this paper, we can infer that wind speed <10 m s −1 generally results in strong to intermediate plumes rising vertically above the crater, whereas wind speed >10 m s −1 is normally associated with weak plumes, bent-over along the wind direction and reaching lower elevations.

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“…Infrasonic array methods are also available to locate the emission in x,y space (Ripepe and Marchetti 2002). Plume front velocities, density and entrainment rates have also been successfully tracked using visible and thermal cameras, as well as radiometers, for a few stronger, ash-rich, buoyant plumes at Stromboli, Santiaguito and Eyjafjallajökull (Patrick 2007;Sahetapy-Engel and Harris 2009;Bjornsson et al 2013;Valade et al 2014) (see Chapter 9 of Harris 2013 for review).…”

Section: How To Link the Geophysical Data With Pyroclast Textural Quamentioning

confidence: 98%

MeMoVolc consensual document: a review of cross-disciplinary approaches to characterizing small explosive magmatic eruptions

et al. 2015

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A workshop entitled “Tracking and understanding volcanic emissions through cross-disciplinary integration: a textural working group” was held at the Université Blaise Pascal (Clermont-Ferrand, France) on the 6–7 November 2012. This workshop was supported by the European Science Foundation (ESF). The main objective of the workshop was to establish an initial advisory group to begin to define measurements, methods, formats and standards to be applied in the integration of geophysical, physical and textural data collected during volcanic eruptions. This would homogenize procedures to be applied and integrated during both past and ongoing events. The workshop comprised a total of 35 scientists from six countries (France, Italy, Great Britain, Germany, Switzerland and Iceland). The four main aims were to discuss and define: standards, precision and measurement protocols for textural analysis; identification of textural, field deposit, chemistry and geophysical parameters that can best be measured and combined; the best delivery formats so that data can be shared between and easily used by different groups; and multi-disciplinary sampling and measurement routines currently used and measurement standards applied, by each community. The group agreed that community-wide, cross-disciplinary integration, centred on defining those measurements and formats that can be best combined, is an attainable and key global focus. Consequently, we prepared this paper to present our initial conclusions and recommendations, along with a review of the current state of the art in this field that supported our discussions

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Thermal-image-derived dynamics of vertical ash plumes at Santiaguito volcano, Guatemala

Cited by 28 publications

References 16 publications

Volcanic plume vent conditions retrieved from infrared images: A forward and inverse modeling approach

Volcanic plume vent conditions retrieved from infrared images: A forward and inverse modeling approach

Paroxysmal Explosions, Lava Fountains and Ash Plumes at Etna Volcano: Eruptive Processes and Hazard Implications

MeMoVolc consensual document: a review of cross-disciplinary approaches to characterizing small explosive magmatic eruptions

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