The dimensions and dynamics of volcanic eruption columns

Sparks, R. S. J.

doi:10.1007/bf01073509

Cited by 406 publications

(264 citation statements)

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“…where C 1 , C 2 and C 3 are the proportionality constants [e.g., Morton et al, 1956;Sparks, 1986;Carazzo et al, 2008].…”

Section: The 1-d Plume Model Of Eruption Columnmentioning

confidence: 99%

“…[8] The 1-D plume model of eruption column [e.g., Sparks, 1986;Woods, 1988Woods, , 1995 is based on the fluid dynamics and thermodynamics model of Morton et al [1956]. In this model, the eruption column is assigned horizontally averaged properties at each height and it is assumed that the pressure of the eruption cloud is equal to the atmospheric pressure at all heights.…”

Section: The 1-d Plume Model Of Eruption Columnmentioning

confidence: 99%

“…The total height of eruption column, the altitude of NBL and the volumetric flow rate at the NBL are calculated as a function of the mass discharge rate at the vent on the basis of a steady 1-D plume model [Sparks, 1986;Woods, 1988Woods, , 1995. The spreading rate (the increase rate of radius) of umbrella cloud is also calculated from the volumetric flow rate at the NBL on the basis of axisymmetrical gravity current model [Holasek et al, 1996b;Sparks et al, 1997].…”

Section: Introductionmentioning

confidence: 99%

“…The eruption column exhausts its thermal energy and loses its buoyancy within the stratified atmosphere. At the neutral buoyancy level (NBL) where the cloud density is equal to that of the atmosphere, the eruption cloud spreads laterally and an umbrella cloud grows [e.g., Sparks, 1986;Woods, 1988].…”

Section: Introductionmentioning

confidence: 99%

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A three‐dimensional numerical simulation of spreading umbrella clouds

Suzuki¹,

Koyaguchi²

2009

J. Geophys. Res.

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[1] During explosive volcanic eruptions, an eruption column buoyantly rises as a turbulent plume, and an umbrella cloud spreads laterally as a gravity current at the neutral buoyancy level. The source conditions of explosive eruptions such as mass discharge rates of magma at vents have been estimated from the field observations (e.g., satellite images) on the height of the eruption columns and the spreading rate of umbrella clouds on the basis of the one-dimensional (1-D) plume model and the gravity current model. However, these simplified models contain empirical constants (entrainment coefficient of turbulent plume, k, and Froude number of gravity current, l) that should be justified. We developed a time-dependent three-dimensional (3-D) numerical model of eruption clouds to independently determine the values of these constants. The 3-D model is designed to calculate quantitative features of turbulent mixing between an eruption cloud and the ambient air without any a priori empirical constants by applying a sufficiently fine grid size with a third-order accuracy scheme. It has reproduced the fundamental features of eruption clouds including eruption columns, pyroclastic flows, coignimbrite ash clouds, and umbrella clouds. The altitudes of the spreading umbrella clouds in the 3-D simulations are consistent with those of the neutral buoyancy level of eruption columns estimated by the 1-D plume model with the entrainment coefficient k $ 0.1. The relationship between the volumetric flow rate and the spreading rate of the umbrella cloud in the 3-D simulations is explained by the axisymmetrical gravity current model with l $ 0.2 for eruption clouds in the tropical atmosphere and l $ 0.1 for those in the midlatitude atmosphere. On the other hand, the total column height in the 3-D simulations strongly oscillates even for a constant mass discharge rate, and its time average tends to be substantially greater than the column height estimated by the 1-D plume model with k $ 0.1, particularly for large-scale eruption clouds in the midlatitude atmosphere. We recommend a method to estimate the mass discharge rate from the observation of the column height or the spreading rate of umbrella cloud. The method and the accuracy of the 3-D simulations are tested on the basis of the field data (e.g., the total height of the eruption column, the altitude and the spreading rate of the umbrella cloud, and the mass discharge rate) of the Pinatubo 1991 eruption.

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“…where C 1 , C 2 and C 3 are the proportionality constants [e.g., Morton et al, 1956;Sparks, 1986;Carazzo et al, 2008].…”

Section: The 1-d Plume Model Of Eruption Columnmentioning

confidence: 99%

Section: The 1-d Plume Model Of Eruption Columnmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A three‐dimensional numerical simulation of spreading umbrella clouds

Suzuki¹,

Koyaguchi²

2009

J. Geophys. Res.

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“…Volcanic eruptions can produce plumes that rise more than 40 km above the Earth's surface [Holasek et al, 1996a], deposit ash over tens of thousands of square kilometers [Sparks, 1986], and disperse gases and aerosols over hemispheric scales [McCormick et al, 1995]. In addition to the dangers posed by ash deposition in populated areas, airborne ash can also be a hazard because of the potential for its ingestion into aircraft engines and their resultant failure [Casadevall, 1994].…”

Section: Introductionmentioning

confidence: 99%

Volcanic eruption plume top topography and heights as determined from photoclinometric analysis of satellite data

Glaze¹,

Wilson²,

Mouginis-Mark³

1999

J. Geophys. Res.

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Modeling ash fall distribution from a Yellowstone supereruption

Mastin

Eaton

Lowenstern

2014

Geochem Geophys Geosyst

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We used the volcanic ash transport and dispersion model Ash3d to estimate the distribution of ashfall that would result from a modern-day Plinian supereruption at Yellowstone volcano. The simulations required modifying Ash3d to consider growth of a continent-scale umbrella cloud and its interaction with ambient wind fields. We simulated eruptions lasting 3 days, 1 week, and 1 month, each producing 330 km 3 of volcanic ash, dense-rock equivalent (DRE). Results demonstrate that radial expansion of the umbrella cloud is capable of driving ash upwind (westward) and crosswind (N-S) in excess of 1500 km, producing more-or-less radially symmetric isopachs that are only secondarily modified by ambient wind. Deposit thicknesses are decimeters to meters in the northern Rocky Mountains, centimeters to decimeters in the northern Midwest, and millimeters to centimeters on the East, West, and Gulf Coasts. Umbrella cloud growth may explain the extremely widespread dispersal of the 640 ka and 2.1 Ma Yellowstone tephra deposits in the eastern Pacific, northeastern California, southern California, and South Texas.

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The dimensions and dynamics of volcanic eruption columns

Cited by 406 publications

References 14 publications

A three‐dimensional numerical simulation of spreading umbrella clouds

A three‐dimensional numerical simulation of spreading umbrella clouds

Volcanic eruption plume top topography and heights as determined from photoclinometric analysis of satellite data

Modeling ash fall distribution from a Yellowstone supereruption

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