{"id":741,"date":"2012-08-16T01:41:22","date_gmt":"2012-08-16T00:41:22","guid":{"rendered":"http:\/\/all-geo.org\/volcan01010\/?p=741"},"modified":"2012-08-30T17:21:55","modified_gmt":"2012-08-30T16:21:55","slug":"ten-swimming-pools","status":"publish","type":"post","link":"https:\/\/all-geo.org\/volcan01010\/2012\/08\/ten-swimming-pools\/","title":{"rendered":"Ten swimming pools of travel chaos"},"content":{"rendered":"

An article published this week reveals the volume, grainsize and eruption rate characteristics of the tephra<\/a> (volcanic ash, pumice and other materials) erupted during the eruption of Eyjafjallaj\u00f6kull in 2010.\u00a0 This information is important because these are the inputs needed by computer simulations to predict where ash from an eruption is likely to be dispersed.\u00a0 It is also interesting because the volume of ash that caused all that travel chaos in Europe turns out to be surprisingly small.<\/p>\n

Ten swimming pools?<\/h3>\n

The group of scientists, led by the University of Iceland, combined measurements of tephra deposited on the ground, meteorological data, satellite data and theoretical models of ash dispersion to work out how much tephra was produced at the volcano at different times during the eruption, and to where it was dispersed.\u00a0 I helped out with measurements of ash deposition across Europe<\/a>.\u00a0 The results were published as open access<\/a>, so you can download the article and read them for yourself here<\/a>.<\/p>\n

The total mass of erupted tephra was 480 million tonnes.\u00a0 Most of this landed in Iceland, however, and only a tiny fraction (0.02%) of this made it as far as mainland Europe.\u00a0 This ash consisted of tiny grains of pulverised rock between 1 and 50 millionths<\/em> of a metre (microns) across.\u00a0 For comparison, an individual red blood cell is about 6-8 microns in diameter.<\/p>\n

Now, a cubic metre of dense Eyjafjallaj\u00f6kull magma would have a mass of about 2.6 tonnes.\u00a0 It would look like rocky grey washing machine, but with no door.\u00a0 So if you compacted all the ash in Europe back into a single lump, it would have a volume of 36,000 cubic metres.\u00a0 This would form a cube with 33 metre sides.\u00a0 It would look like a rocky grey 11-storey building, but with no windows.<\/p>\n

To continue in the Olympic spirit, we can calculate how many swimming pools this would fill.\u00a0 The standard competition pool<\/a> is 50 x 25 x 2 m, but the one in London was actually 3 m deep, so that waves would be reduced<\/a> and the swimmers could go faster.\u00a0 The volume is therefore 3750 cubic metres.<\/p>\n

This means that, theoretically, all the travel chaos of Eyjafjallaj\u00f6kull was caused by magma with a volume of only ten Olympic-sized swimming pools.<\/p>\n

This seems unbelievable, but remember that huge volumes of air get sucked through jet engines, so even low ash concentrations can quickly add up to trouble.\u00a0 Airlines now have to take special measures if the concentration exceeds two thousandths of a gram <\/em>per cubic metre, so to keep aeroplanes out of your swimming pool needs only 7.5 grams of tephra.\u00a0 That’s about a quarter of a teaspoon.<\/p>\n

EDIT (30 Aug 2012):<\/em><\/strong> Of course, the chaos wasn’t caused by the ash itself, but by the rules that stopped planes from flying where the ash might be.\u00a0 These were changed as the Eyjafjallaj\u00f6kull 2010 eruption was ongoing, and the 2 milligrams per cubic metre limit was introduced.\u00a0 This means that you can now have a much more powerful eruption in Iceland, but with much less disruption.<\/p>\n

In fact, we already have: http:\/\/all-geo.org\/volcan01010\/2012\/04\/an-icelandic-eruption-100-times-more-powerful-than-eyjafjallajokull\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

An article published this week reveals the volume, grainsize and eruption rate characteristics of the tephra (volcanic ash, pumice and other materials) erupted during the eruption of Eyjafjallaj\u00f6kull in 2010.\u00a0 This information is important because these are the inputs needed … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-741","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/all-geo.org\/volcan01010\/wp-json\/wp\/v2\/posts\/741","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/all-geo.org\/volcan01010\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/all-geo.org\/volcan01010\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/all-geo.org\/volcan01010\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/all-geo.org\/volcan01010\/wp-json\/wp\/v2\/comments?post=741"}],"version-history":[{"count":18,"href":"https:\/\/all-geo.org\/volcan01010\/wp-json\/wp\/v2\/posts\/741\/revisions"}],"predecessor-version":[{"id":745,"href":"https:\/\/all-geo.org\/volcan01010\/wp-json\/wp\/v2\/posts\/741\/revisions\/745"}],"wp:attachment":[{"href":"https:\/\/all-geo.org\/volcan01010\/wp-json\/wp\/v2\/media?parent=741"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/all-geo.org\/volcan01010\/wp-json\/wp\/v2\/categories?post=741"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/all-geo.org\/volcan01010\/wp-json\/wp\/v2\/tags?post=741"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}