A numerical model of ballistic transport with collisions in a volcanic setting

Tsunematsu, Kae; Chopard, Bastien; Falcone, Jean-Luc; Bonadonna, Costanza

doi:10.1016/j.cageo.2013.10.016

Cited by 21 publications

(38 citation statements)

References 19 publications

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“…Clast-clast interactions as presented in a b Fig. 5 Illustration of the von Mises-Fisher distribution with a) an upright mean direction (plotted in red) and κ = 5, corresponding to a central explosion and b) a northward inclined mean direction (plotted in red) and κ = 10, corresponding to an explosion from the northern vent Tsunematsu et al (2014) and the effects of tailwind are ignored in these simulations.…”

Section: Assessment Of Probabilities Of Ballistic Impacts On Ruapehu'mentioning

confidence: 99%

Phreatic eruptions at crater lakes: occurrence statistics and probabilistic hazard forecast

et al. 2017

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Phreatic eruptions, although posing a serious threat to people in crater proximity, are often underestimated and have been comparatively understudied. The detailed eruption catalogue for Ruapehu Volcano (New Zealand) provides an exceptional opportunity to study the statistics of recurring phreatic explosions at a crater lake volcano. We performed a statistical analysis on this phreatic eruption database, which suggests that phreatic events at Ruapehu do not follow a Poisson process. Instead they tend to cluster, which is possibly linked to an increased heat flow during periods of a more shallow-seated magma column. Larger explosions are more likely to follow shortly after smaller events, as opposed to longer periods of quiescence. The absolute probability for a phreatic explosion to occur at Ruapehu within the next month is about 10%, when averaging over the last 70 years of recording. However, the frequency of phreatic explosions is significantly higher than the background level in years prior to magmatic episodes. Combining clast ejection simulations with a Bayesian event tree tool (PyBetVH) we perform a probabilistic assessment of the hazard due to ballistic ejecta in the summit area of Ruapehu, which is frequently visited by hikers. Resulting hazard maps show that the absolute probability for the summit to be affected by ballistics within the next month is up to 6%. The hazard is especially high on the northern lakeshore, where there is a mountain refuge. Our results contribute to the local hazard assessment as well as the general perception of hazards due to steam-driven explosions.

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Section: Assessment Of Probabilities Of Ballistic Impacts On Ruapehu'mentioning

confidence: 99%

Phreatic eruptions at crater lakes: occurrence statistics and probabilistic hazard forecast

et al. 2017

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“…This model suggests that at least some parts of the cones grow by accumulation of clasts falling from an eruption jet column above the vent. Deposition by jet fallout was observed in situ at some scoria cones (Valentine et al, 2005) as partly contributing factor. Also, at least 50% of the ejected volume might be non-ballistically deposited around the cone as a thin ash blanket (Riedel et al, 2003), which would be hardly observable by remote sensing data in topographic profiles.…”

Section: Introductionmentioning

confidence: 95%

“…The distribution of ballistically ejected material depends on particle size and density, initial velocity, the angle of ejection from the vent and the frequency of collisions between particles (Tsunematsu et al, 2014). The final shape of the cone is controlled by the ballistic range of scoria particles and the total volume of generated scoria.…”

Section: Introductionmentioning

confidence: 99%

Shape of scoria cones on Mars: Insights from numerical modeling of ballistic pathways

Brož

Čadek

Hauber³

et al. 2014

Earth and Planetary Science Letters

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Morphological observations of scoria cones on Mars show that their cross-sectional shapes are different from those on Earth. Due to lower gravity and atmospheric pressure on Mars, particles are spread over a larger area than on Earth. Hence, erupted volumes are typically not large enough for the flank slopes to attain the angle of repose, in contrast to Earth where this is common. The distribution of ejected material forming scoria cones on Mars, therefore, is ruled mainly by ballistic distribution and not by redistribution of flank material by avalanching after the static angle of repose is reached. As a consequence, the flank slopes of the Martian scoria cones do not reach the critical angle of repose in spite of a large volume of ejected material. Therefore, the topography of scoria cones on Mars is governed mainly by ballistic distribution of ejected particles and is not influenced by redistribution of flank material by avalanching. The growth of a scoria cone can be studied numerically by tracking the ballistic trajectories and tracing the cumulative deposition of repeatedly ejected particles. We apply this approach to a specific volcanic field, Ulysses Colles on Mars, and compare our numerical results with observations. The scoria cones in this region are not significantly affected by erosion and their morphological shape still preserves a record of physical conditions at the time of eruption. We demonstrate that the topography of these scoria cones can be rather well (with accuracy of ∼10 m) reproduced provided that the ejection velocities are a factor of ∼2 larger and the ejected particles are about ten times finer than typical on Earth, corresponding to a mean particle velocity of ∼92 m/s and a real particle size of about 4 mm. This finding is in agreement with previous theoretical works that argued for larger magma fragmentation and higher ejection velocities on Mars than on Earth due to lower gravity and different environmental conditions.

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“…This amount of abnormal trajectories is significantly higher than the value obtained by Dürig et al [2015] for the Eyjafjallajökull 2010 eruption (97 clast-clast collisions over thousands of ejecta) but it is consistent when taking into account the metric-size of the projectiles for Tungurahua's case. Tsunematsu et al [2014] show that larger particles have higher probability to experience one or more collisions.…”

Section: Hazard Assessment Of Volcanic Ballistic Projectilesmentioning

confidence: 92%

“…In the distribution histogram, the outer values (<-30 m and >+40 m) represents only 11.5% of all trajectories and could be associated to trajectories modified by processes such as block fragmentation and collision processes during flight [Vanderkluysen et al 2012;Tsunematsu et al 2014;Taddeucci et al 2017]. This amount of abnormal trajectories is significantly higher than the value obtained by Dürig et al [2015] for the Eyjafjallajökull 2010 eruption (97 clast-clast collisions over thousands of ejecta) but it is consistent when taking into account the metric-size of the projectiles for Tungurahua's case.…”

Section: Hazard Assessment Of Volcanic Ballistic Projectilesmentioning

confidence: 99%

Rapid hazard assessment of volcanic ballistic projectiles using long-exposure photographs: insights from the 2010 eruptions at Tungurahua volcano, Ecuador

Bernard

2018

Volcanica

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Assessing hazard associated to volcanic ballistic projectiles is essential to limit fatal incidents close to erupting vents. Current state-of-the-art methods using high-speed visual and thermal images and volcanic radars permit to obtain high resolution information during explosive events but are limited to few laboratory volcanoes. Nowadays, long-exposure photographs at erupting volcanoes have become common and can be used to obtain meaningful information. In this paper I present a method to extract volcano-physical data from the projectile parabolic trajectory after adequate scaling and projection. The results, obtained from the analysis of 28 photographs from three eruptive phases at Tungurahua volcano in 2010, allowed to constrain the geometry of the vent (20 m-diameter upper conduit and 70 m-diameter inner crater), the diameter of the ballistic projectiles (up to 4.3 m), their launching angle (50 to 90°), their minimum launching velocity (40 to 145 m s −1 ), and their maximum range (up to 1400 m from the vent) for low to moderate explosive activity, outside paroxysms. This turnkey method can help to characterize eruptive dynamics as well as to perform rapid hazard assessment at dangerously explosive erupting volcanoes.

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A numerical model of ballistic transport with collisions in a volcanic setting

Cited by 21 publications

References 19 publications

Phreatic eruptions at crater lakes: occurrence statistics and probabilistic hazard forecast

Phreatic eruptions at crater lakes: occurrence statistics and probabilistic hazard forecast

Shape of scoria cones on Mars: Insights from numerical modeling of ballistic pathways

Rapid hazard assessment of volcanic ballistic projectiles using long-exposure photographs: insights from the 2010 eruptions at Tungurahua volcano, Ecuador

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