JF Ptak Science Books Quick Post
I came to this terrible majesty/rex tremendae of words browsing an 1883 volume of Nature, landing on two articles on the Krakatoa eruption of 26-7 August 1883. The editors were just then coming to grips with what scant information came their way, though they knew that what they were trying to present to their readers was a very major event. There was little to prepare them for what they would understand the eruption to be, no doubt filling themselves with images of dread (Quantus tremor est futurus, "what horror invades the mind", calling again--sorry!--on Mozart's Requiem for the appropriate language).
The eruption is well known and the subject of innumerable stories and papers, so I'll not get into that. I do want to look at the expansive and changling vocabulary describing these events, though. The way eruptions are categorized in modern times for relative description and is the Volcanic Explosivity Index (the VEI). a logarithmic scale which runs 0-8. The basis of categorizing the terrific nature of the eruption is made in terms of the volume of ejecta, the plume height, length of eruption, and that sort. I find the defining terms of type of eruption to be very entertaining, with eruptions being described as (level VFI 0) effusive, (1) gentle, (2) explosive, (3) catastrophic, (4) cataclysmic, (5) peroxysmic, (6) colossal, and of course (7) super-colossal, and (8) mega-colossal. (Just a quick note: "colossal" appears in the OED by 1664; "supercolossal" as an unhyphenated word appears by 1875; and "mega-colossal" just doesn't appear.)
Krakatoa was a VFI-6, a peroxysmic event with 10 km3 of ejecta, which is 1 billion meters3, or 1 trillion litres, or 264 billion gallons (which would weigh in at 1.8 trillion pounds, or about the equivalent of 17,819.7 Titanics), or about 10 times the ejecta of the 1980 Mt. St. Helen's eruption. These are very messy approximations as ejecta is varied, but it does give you an idea of the magnitude of what was going on.
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