Are We Ready?
If you were one of the 10 million air travellers shaking your fist at the departures board in April 2010, you will appreciate the fact that – even in this tectonically peaceful realm – we ignore volcanic threats at our peril. Despite being nothing to write home about in terms of size, the eruption from Iceland’s Eyjafjallajökull volcano brought air travel chaos to the UK and mainland Europe when its ash cloud grounded an astonishing 107,000 flights in the biggest air traffic shutdown since the second world war. The eight days of mayhem brought airline CEOs to the point of apoplexy and, once the ash had settled, the air travel business was left with a €1.3bn bill. The threat posed by Icelandic eruptions has since been recognised and added, retrospectively, to the UK’s National Risk Register, in the hope that next time we will be better prepared. But what about volcanic explosions further afield? These, it appears, are still regarded as posing no threat to our country, and so can be safely ignored. But turn the clock back 200 years and there is at least one event that suggests we ought to think twice.
In April 1815, the biggest known eruption of the historical period blew apart the Tambora volcano, on the Indonesian island of Sumbawa, 12,000km from the UK. What happened next testifies to the enormous reach of the biggest volcanic blasts.
The Tambora volcano had shown no signs of life for 1,000 years; a single eruption in the previous five millennia provided the only indication that magma was still churning far beneath. It is very likely that the residents of the island considered the volcano extinct, and possible even that they did not know the impressive 4,300m (14,107ft) mountain – at the time, probably the highest in the East Indies – was a volcano at all. This all changed, however, with the rumblings and earthquakes of 1812, a full three years before the climactic blast. Over time, the seismic shocks were superseded by steam blasts and small ash explosions, engendering increasing trepidation on the island and signalling that something bigger might be imminent. It was. On 5 April 1815, a titanic explosion hurled a cloud of ash to a height of more than 30km. Violent, but short-lived, the blast lasted just two hours, after which the volcano returned to a state of brooding menace. According to the lieutenant governor, Thomas Stamford (later Sir Stamford) Bingley Raffles, to whom volcanologists are indebted for his accounts of the eruption, the detonation was so loud that it was mistaken across Java for cannon fire, causing consternation among the British troops, which had ousted the Dutch and French forces just a few years earlier.
But the blast was small beer in comparison with what followed. After five days of relative calm, the climactic phase of the eruption began with a colossal explosion that launched a towering column of ash to the edge of space. For four or five days, utter blackness reigned across the island as the hurricane blasts of hot ash and scalding gas – known as pyroclastic flows – scoured the flanks of the volcano of everything and everyone, and drifts of ash metres thick entombed what few signs of life remained. When the explosions ceased and the darkness finally lifted, the view revealed was a vision of Tolkien’s Mordor; a grey landscape within which nothing lived or moved. The top 500m of the volcano was gone, blasted into smithereens, and replaced by a 6km-wide maw from which steam spiralled skywards. Communities on the flanks of the volcano had vanished, along with the lives of around 12,000 men, women and children. These, perhaps, were the lucky ones, as a further 60,000 survivors of the eruption succumbed slowly and agonisingly to famine or disease.
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