Nature
PUBLISHED
The predicted eruption of Iceland's Bárðarbunga has begun. Or maybe it hasn't. Predicting volcanic eruptions is hard, but you'd think it would be easy to know when one is happening. However, when the volcano lies under hundreds of meters of ice things can be a bit trickier.
The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.There have been signs for a week that Bárðarbunga was about to let off some steam. While some people worried about a repetition of the disruption caused by Eyjafjallajökull in 2010, volcanologists explained nothing similar was likely.
On Saturday the Icelandic Meteorological Office reported that the eruption had begun. However, later that day they noted, “there are no signs of ongoing volcanic activity.” Surface conditions were unchanged, and with no meltwater beyond seasonal norms observed downriver the announcement was withdrawn. Alert levels initially remained at red since, “an imminent eruption cannot be excluded”, but have since been lowered.
Bárðarbunga lies near the center of Iceland and is covered by between 150 and 400m of ice, even in summer. The signs of eruption are concentrated to the north and east of the main caldera. Earthquakes have rattled the area since August 16, attributed to magma rising in the depths and forming a dike a few kilometers deep.
For Iceland, the situation is normal, the consequence of sitting on both the mid-Atlantic ridge and a mantle hotspot. An Icelandic volcano erupts roughly every five years, and Bárðarbunga itself has exploded an average of every twenty years for more than seven millennia.
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