Satellite observations and interpretation of the 1991 Mount Pinatubo eruption plumes

Holasek, Rick E.; Self, Stephen; Woods, Andrew W.

doi:10.1029/96jb01179

Cited by 185 publications

(241 citation statements)

References 22 publications

Supporting

Mentioning

231

Contrasting

Unclassified

Order By: Relevance

“…Horizontal dashed line in Figure 8b is the time average after 500 s ( _ V exp 3D ). [Koyaguchi and Tokuno, 1993;Holasek et al, 1996a] are also plotted in Figure 9a. We compare the results of 3-D simulations with these observed data in section 5.…”

Section: Entrainment Coefficientmentioning

confidence: 99%

“…Holasek et al [1996a] suggested that the value of l ranges from 0.1 to 0.6 from comparisons with laboratory experiments [Holasek et al, 1996b] and field observations [Woods and Kienle, 1994]; however, this range is too wide for the reconstruction of the dynamics of eruption clouds, because the estimate of _ V by equation (2) sensitively depends on the assumed value of l.…”

Section: Dmentioning

confidence: 99%

“…The volcanic gas is assumed to be water vapor. The conditions of simulations were set to cover those of the Pinatubo 1991 eruption ( _ m 0 = 10 8 -10 9 kg s À1 [Holasek et al, 1996a;Koyaguchi and Ohno, 2001b]: the mass discharge rates _ m 0 estimated from the observations are discussed in section 5). Tables 1 and 2 list the parameters used and the initial conditions for the simulations, respectively.…”

Section: General Features Of Eruption Cloudsmentioning

confidence: 99%

“…A large eruption cloud was observed from the satellite image and its dimensions were estimated from the shadow of the cloud; the total column height was up to 40 km at the first stage of eruption and the altitude of top surface of the umbrella cloud was 25 km at its edge [Tanaka et al, 1991;Koyaguchi and Tokuno, 1993;Holasek et al, 1996a]. The cloud expanded up to 280 km in diameter (60,000 km 2 ) at 1440 LT and 400 km in diameter (120,000 km 2 ) at 1540 LT.…”

Section: Application To the Pinatubo 1991 Eruptionmentioning

confidence: 99%

“…They are obtained from satellite images [e.g., Koyaguchi and Tokuno, 1993;Holasek et al, 1996a] and from other field observations, and they reflect the source conditions at the vent such as mass discharge rate. The relationship between the ob-servable quantities and the source conditions has been the central issue of the dynamics of eruption clouds.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

A three‐dimensional numerical simulation of spreading umbrella clouds

Suzuki¹,

Koyaguchi²

2009

J. Geophys. Res.

View full text Add to dashboard Cite

[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.

show abstract

Section: Entrainment Coefficientmentioning

confidence: 99%

Section: Dmentioning

confidence: 99%

Section: General Features Of Eruption Cloudsmentioning

confidence: 99%

Section: Application To the Pinatubo 1991 Eruptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A three‐dimensional numerical simulation of spreading umbrella clouds

Suzuki¹,

Koyaguchi²

2009

J. Geophys. Res.

View full text Add to dashboard Cite

show abstract

Testing the accuracy of a 1‐D volcanic plume model in estimating mass eruption rate

Mastin

2014

JGR Atmospheres

111

View full text Add to dashboard Cite

During volcanic eruptions, empirical relationships are used to estimate mass eruption rate from plume height. Although simple, such relationships can be inaccurate and can underestimate rates in windy conditions. One-dimensional plume models can incorporate atmospheric conditions and give potentially more accurate estimates. Here I present a 1-D model for plumes in crosswind and simulate 25 historical eruptions where plume height H obs was well observed and mass eruption rate M obs could be calculated from mapped deposit mass and observed duration. The simulations considered wind, temperature, and phase changes of water. Atmospheric conditions were obtained from the National Center for Atmospheric Research Reanalysis 2.5°model. Simulations calculate the minimum, maximum, and average values (M min , M max , and M avg ) that fit the plume height. Eruption rates were also estimated from the empirical formula M empir = 140H obs 4.14 (M empir is in kilogram per second, H obs is in kilometer). For these eruptions, the standard error of the residual in log space is about 0.53 for M avg and 0.50 for M empir . Thus, for this data set, the model is slightly less accurate at predicting M obs than the empirical curve.The inability of this model to improve eruption rate estimates may lie in the limited accuracy of even well-observed plume heights, inaccurate model formulation, or the fact that most eruptions examined were not highly influenced by wind. For the low, wind-blown plume of 14-18 April 2010 at Eyjafjallajökull, where an accurate plume height time series is available, modeled rates do agree better with M obs than M empir .

show abstract

Modeling ash fall distribution from a Yellowstone supereruption

Mastin

Eaton

Lowenstern

2014

Geochem Geophys Geosyst

View full text Add to dashboard Cite

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.

show abstract

Satellite observations and interpretation of the 1991 Mount Pinatubo eruption plumes

Cited by 185 publications

References 22 publications

A three‐dimensional numerical simulation of spreading umbrella clouds

A three‐dimensional numerical simulation of spreading umbrella clouds

Testing the accuracy of a 1‐D volcanic plume model in estimating mass eruption rate

Modeling ash fall distribution from a Yellowstone supereruption

Contact Info

Product

Resources

About