Green.view: Could be worse
Why the Icelandic eruption is peculiarly troublesome for one so smallICELAND has a lot of volcanoes, and it’s a rare decade where one of them doesn’t erupt. So why is the eruption of Eyjafjallajokull causing such chaos, and what does that mean for the future? The answer to the first question is that the Eyjafjallajokull eruption is peculiarly well attuned to messing with air travel; most eruptions of a similar size would do a lot less long-distance harm. The answer to the second is that less well attuned but considerably larger eruptions are all but certain in decades to come.The earth’s volcanoes appear for the most part in three types of setting. The most familiar, and most of the most dangerous, are found where one tectonic plate overrides another, as happens in the ring of fire around the Pacific. Then there are those which sit over isolated “hotspots” of upwelling magma from deep in the earth, like the volcanoes of Hawaii. Finally there are those—a great many, but normally deep under the ocean—formed at the spreading ridges where tectonic plates pull away from each other and new crust is formed. Iceland is peculiarly volcanic because it is formed by the intersection of a hotspot and a mid-ocean ridge. The hotspot has pushed the spreading ridge up to the surface and supplemented its activities with some extra volcanism on the side. There are 33 large volcanoes on the island, or just offshore, which have erupted since the end of the last ice age, around 12,000 years ago. ...
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