Back in April scientists announced that they had discovered a second gigantic magma chamber underneath Yellowstone national park. Big enough to fill up the Grand Canyon 11 times over, the chamber, which is full of non-erupting crystalline “mush”, was discovered by studying the reflection pattern of seismic waves. So how many other volcanoes might be hiding magma chambers underneath them?
The answer is probably hundreds. Monitoring volcanoes is expensive so most countries only monitor the volcanoes considered to be the most dangerous. If a magma chamber starts to inflate rapidly then an eruption is likely due. Uturunku in Peru is a good example: the land around the volcano has been rising at up to 2cm per year since the 1990s, suggesting it is refuelling. But not all volcanoes show obvious eruption precursors. “Hekla in Iceland is well understood and monitored. But we still only get around 20 minutes notice that it’s going to erupt. Which is why I won’t climb it,” says volcanologist Dave McGarvie, from The Open University.
Seemingly benign volcanoes can be the most dangerous. “There are hundreds of volcanoes that have eruptive cycles in the 500-1000 year period (or longer). They are perceived to be inactive, so they are not closely monitored, thus they can erupt with little or no warning – the 2008 eruption of Chaiten in Chile was a great example,” cautions McGarvie. And even if we did know about the magma chambers under these volcanoes, we would have to monitor them continuously to spot the last-minute inflation and magma refueling that occurs just before an eruption.
Twitter: @katerav
