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Friday, 22 July 2016

Santorini was even bigger

From 1995 to 2005, I worked as a science journalist, and so I used to get a lot of press releases crossing my desk. For that matter, I still do, but by now, I know most of the patterns. One of these is the way US geologists and geophysicists manage to spend the northern summer in holiday destinations, studying the local geology.

I would never be so cynical as to suggest that these worthy people had wangled a grant that also gave them a holiday, but I suspect that more than a few may have realised that this gave them the chance to write their holiday off as a tax deduction. Well, governments don't do all that much for science, so more power to them!

The result of all this vacation activity is that in the Australian spring, papers, reports and press releases bob up that explain things like how the Delphic oracle was a lady intoxicated by volcanic gases, or studying the geology of the Acropolis, or the ophiolites of the Troodos Mountains on Cyprus — Greek destinations seem to be all the go.

Map of Santorini, Lyell's Principles, vol. 2
So in 2006, I decided to follow suit, and accompanied by my loyal assistant (aka my wife Chris, a science teacher, though she was on holiday and I was working), I spent a month in the Greek Islands this past northern summer, including a visit to Santorini. This island is a volcanic remnant, a part of the crater rim, with a small volcanic remnant in the middle. We noticed a large number of Americans and Japanese there, but apparently some were in the area with more serious intentions than trying the local wines, which seems to be what most of the tourists do when they aren't poking around the volcanic bits, as tourists.

The volcano blew, somewhere around 1600 BC, sending an estimated 39 cubic kilometres of magma and rock into the sky. The resulting tsunami is supposed to have wiped out the Minoan civilisation on Crete, and a few brave souls even suggest that it was the basis of a few Middle Eastern flood myths (I don't buy it, but that may not mean anything). Others think it may have been the basis of the Atlantis myth.

Inside the crater
To put this in perspective, the eruption of Mount Tambora in Indonesia in 1815 is the largest known volcanic eruption, with approximately 100 cubic kilometres of material ejected.

The much-smaller Krakatau (Krakatoa, if you are old-fashioned) eruption of 1883 in Indonesia created a 30-metre-high tsunami that killed 36,000 people, as well as pyroclastic flows that travelled 40 kilometres across the surface of the seas killing 1,000 people on nearby islands.

Two expeditions in the northern summer of 2006 reassessed the explosion, finding deposits of volcanic pumice and ash 10 to 80 metres thick extending out 20 to 30 kilometres in all directions from Santorini. Based on this, they have raised the estimate to 60 cubic kilometres.

Nice walking, too!
Either way, you might think the tourist authorities might like to hush the matter up — that little volcanic island out in the bay goes off every so often, but it seems the punters like a bit of a gamble with fate, a dice with the devil.

Luckily, while we still cannot predict earthquakes, eruptions are much easier to predict, a month or so out from the event.

Still, now I think I will have to go back again.

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