The development of a multidisciplinary plan for evaluation of the long-term health effects of the Mount St. Helens eruptions.

Buist, A. Sonia; Martin, Thomas R.; Shore, J H; Butler, Jrg; Lybarger, Jeffrey A.

doi:10.2105/ajph.76.suppl.39

Cited by 10 publications

(7 citation statements)

References 8 publications

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“…12, for the total GSDs (see text for discussion) serious health hazards of fine ash is growing (e.g. Bernstein et al 1986;Buist et al 1986;Baxter et al 1999), and the possible association of concentrations of fine ash with milling by pyroclastic flows is notable.…”

Section: Tephra Dispersal Pattern For the October 14 1974 Eruptionmentioning

confidence: 99%

Nature and significance of small volume fall deposits at composite volcanoes: Insights from the October 14, 1974 Fuego eruption, Guatemala

et al. 2007

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The first of four successive pulses of the 1974 explosive eruption of Fuego volcano, Guatemala, produced a small volume (∼0.02 km3 DRE) basaltic sub-plinian tephra fall and flow deposit. Samples collected within 48 h after deposition over much of the dispersal area (7–80 km from the volcano) have been size analyzed down to 8 φ (4 µm). Tephra along the dispersal axis were all well-sorted (σ φ = 0.25–1.00), and sorting increased whereas thickness and median grain size decreased systematically downwind. Skewness varied from slightly positive near the vent to slightly negative in distal regions and is consistent with decoupling between coarse ejecta falling off the rising eruption column and fine ash falling off the windblown volcanic cloud advecting at the final level of rise. Less dense, vesicular coarse particles form a log normal sub-population when separated from the smaller (Mdφ < 3φ or < 0.125 mm), denser shard and crystal sub-population. A unimodal, relatively coarse (Mdφ = 0.58φ or 0.7 mm σ φ = 1.2) initial grain size population is estimated for the whole (fall and flow) deposit. Only a small part of the fine-grained, thin 1974 Fuego tephra deposit has survived erosion to the present day. The initial October 14 pulse, with an estimated column height of 15 km above sea level, was a primary cause of a detectable perturbation in the northern hemisphere stratospheric aerosol layer in late 1974 to early 1975. Such small, sulfur-rich, explosive eruptions may substantially contribute to the overall stratospheric sulfur budget, yet leave only transient deposits, which have little chance of survival even in the recent geologic record. The fraction of finest particles (Mdφ = 4–8φ or 4–63 µm) in the Fuego tephra makes up a separate but minor size mode in the size distribution of samples around the margin of the deposit. A previously undocumented bimodal–unimodal–bimodal change in grain size distribution across the dispersal axis at 20 km downwind from the vent is best accounted for as the result of fallout dispersal of ash from a higher subplinian column and a lower “co-pf” cloud resulting from pyroclastic flows. In addition, there is a degree of asymmetry in the documented grain-size fallout pattern which is attributed to vertically veering wind direction and changing windspeeds, especially across the tropopause. The distribution of fine particles (<8 µm diameter) in the tephra deposit is asymmetrical, mainly along the N edge, with a small enrichment along the S edge. This pattern has hazard significance

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Section: Tephra Dispersal Pattern For the October 14 1974 Eruptionmentioning

confidence: 99%

Nature and significance of small volume fall deposits at composite volcanoes: Insights from the October 14, 1974 Fuego eruption, Guatemala

et al. 2007

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“…Concentrations indoors would be much lower (see also BSC 2004 [DIRS 169458], Section 6.2). It should be noted that high ambient concentrations reported here do not result in an under-representation of the risk estimate because they likely are overestimates of concentrations inhaled because it is well documented that during volcanic eruptions people take actions, such as staying indoors and wearing masks, to reduce the amount of ash they inhale (Johnson et al 1982 [DIRS 164149]; Buist et al 1986 [DIRS 144632]; Nania et al 1994 [DIRS 164156]). …”

Section: Mass Loading Levels During Volcanic Eruptionmentioning

confidence: 87%

Disruptive Event Biosphere Dose Conversion Factor Analysis

Wasiolek¹

2004

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“…The presence of the characteristics at the analogue sites considered in this analysis, and their effects on measurements of resuspended particles considered here, are unknown. For example, measurements of mass loading taken over the tephra deposit from the eruption of basaltic Cerro Negro (Hill and Conner 2000 [DIRS 160103], p. 71) are higher than analogous measurements taken following the eruption of the silicic Mount St. Helens (Buist et al 1986 [DIRS 1446321, Table 2; Merchant et al 1982 [DIRS 160102], Table 6) (see Section 6.2.1). To account for uncertainty about the influence of differences in the characteristics of ash from analogue measurements considered here and the potential conditions in the reference biosphere following an eruption, the modal and lower bounds of the distribution of the decay constant described below are smaller (i.e., have a slower decay rate) than the value of about 2 measured after eruptions of Mount St. Helens and Mount Spurr.…”

Section: Inhalation Exposure Input Parameters For the Biosphere Modelmentioning

confidence: 99%

Inhalation Exposure Input Parameters for the Biosphere Model

Rautenstrauch¹

2004

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The development of a multidisciplinary plan for evaluation of the long-term health effects of the Mount St. Helens eruptions.

Cited by 10 publications

References 8 publications

Nature and significance of small volume fall deposits at composite volcanoes: Insights from the October 14, 1974 Fuego eruption, Guatemala

Nature and significance of small volume fall deposits at composite volcanoes: Insights from the October 14, 1974 Fuego eruption, Guatemala

Disruptive Event Biosphere Dose Conversion Factor Analysis

Inhalation Exposure Input Parameters for the Biosphere Model

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