Australian researchers have unlocked a secret hidden in the fiery heart of many volcanoes, which could lead to better detection of when they might erupt.
While volcanoes commonly form at the places on Earth where tectonic plates join, hotspot volcanoes can form anywhere and are fed by magma being pushed through cracks in the plates by convection currents of the magma below the Earth’s crust.
Geologists previously believed the lava that flows out of hotspot volcanoes is “pristine” and from deep within the Earth. However, University of Queensland researchers have now discovered that it is actually from a much shallower depth.
UQ volcanologist Dr Teresa Ubide said they realised hotspot volcanoes had a natural “filter” that sifted out impurities in the lava, making it seem like it was from much deeper in the Earth.
“This lava is a bit like a rocky road chocolate – if you did a chemical analysis of it, you would get a mixture of the marshmallows, the nuts, and so on,” Dr Ubide said.
“What we realised was that if we analyse the lava alone, without the marshmallows and nuts, so to speak, then the chemistry is very different, and actually, it indicates it’s from much shallower than was previously thought.”
It was initially thought that the magma feeding hotspot volcanoes came from about 50 kilometres below the surface, however the research indicates it could come from “only” about 15 kilometres down.
The researchers looked at lava samples from El Hierro island in the Canary Islands and found they matched many other samples from similar hotspot volcanoes.