76:. However, the challenge to making these estimates is accurately estimating the density of the tephra deposit or of the dense rock, measuring the thickness of tephra, determining if the tephra is related to the eruption studied or to a nearby one, and estimating changes resulting from other geological processes that may be less understood than on
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Historical and geological estimates of tephra volumes are usually obtained by mapping the distribution and thickness of tephra deposits on the ground after the eruption is over. For historical volcanic explosions, further estimates must be made of tephra deposits that might have changed
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Watkins, ND; Sparks, RSJ; Sigurdsson, H; Huang, TC; Federman, A; Carey, S; Ninkovich, D (1978). "Volume and extent of the Minoan tephra from
Santorini Volcano: new evidence from deep-sea sediment cores".
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significantly over time by other geological processes including erosion. Tephra volumes measured in this way must then be corrected for void spaces (
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Thera and the Aegean World III. Volume Two: "Earth
Sciences" Proceedings of the Third International Congress, Santorini, Greece, 3–9 September 1989
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of the original gas-free rock-type that makes up the tephra. The result is referred to as the dense-rock equivalent of the erupted volume.
61:– bubbles within the pumice, empty spaces between individual pieces of pumice or ash) to get an estimate of the original volume of
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Dense-rock equivalent calculations can also be used to measure the sizes of volcanic eruptions on other planetary bodies, such as
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during an effusive phase of a volcanic eruption. Eruption volumes are commonly expressed in cubic kilometers (km).
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volume. One of the widely accepted measures of the size of a historic or prehistoric eruption is the volume of
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erupted. This correction can be made by comparing the bulk density of the tephra deposit with the known
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181:"Estimation of volcanic eruption conditions for a large flank event on Elysium Mons, Mars"
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cultures. Through careful analysis of pumice and ash deposits (including
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to better understand the effect of the eruption on development of several
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Significant studies of the dense-rock equivalent erupted volumes of the
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during an explosive phase of the eruption, or the volume of
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Pages displaying short descriptions of redirect targets
157:. U.S. Geological Survey. 1999-11-30. Archived from
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Volcanologic calculation to estimate eruption volume
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155:Long Valley Observatory Volcano Hazards Program
232:. The Thera Foundation. pp. 113–121.
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179:Wilson, L; Mouginis-Mark, PJ (2001).
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185:Journal of Geophysical Research
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26:calculation used to estimate
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151:"A Note on Eruption Sizes"
127:Volcanic Explosivity Index
94:have provided data to
20:Dense-rock equivalent
206:10.1029/2000JE001420
279:1978Natur.271..122W
197:2001JGR...10620621W
191:(E9): 20621–20628.
273:(5641): 122–126.
246:on 21 August 2007
226:Pyle, DM (1989).
28:volcanic eruption
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287:10.1038/271122a0
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159:the original
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115:core samples
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40:volcanic ash
24:volcanologic
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315:Volcanology
42:, known as
34:ejected as
22:(DRE) is a
309:Categories
250:2007-08-05
212:2007-04-15
165:2007-03-15
137:References
102:including
85:Bronze-Age
320:Volcanoes
92:Santorini
121:See also
112:deep sea
59:vesicles
51:extruded
295:4210868
275:Bibcode
193:Bibcode
67:density
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267:Nature
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44:tephra
36:pumice
291:S2CID
78:Earth
63:magma
32:magma
234:ISBN
106:and
74:Mars
48:lava
38:and
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