SYDNEY (AFP) – Inaudible sonic rumblings from deep in a volcano’s bowels could provide a warning when it is about to blow, scientists said yesterday, offering threatened communities the prospect of a life-saving heads-up.
A team studying “infrasounds” – sounds too deep for humans to hear – from volcanoes like Italy’s Mount Etna has discovered that magmatic gurgles change markedly as an eruption nears.
As magma explodes, soundwaves reverberate through the crater “just like in some brass musical instrument, like a trombone, for example, you get certain notes”, explained Leighton Watson, a University of Canterbury researcher who was part of a multi-national team.
As the magma moves upward, the note changes – like the moving of a trombone arm he told AFP.
Before Etna belched smoke and ash high into the air in February 2021, its tune started to change.
“The peak frequency increased and increased and increased, and the reason for that was the magma was rising up in the crater.”
By figuring out which notes equate to each magma level, predictions could be made about future eruptions.