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Swift
2013-Jul-16, 05:57 PM
From the BBC (http://www.bbc.co.uk/news/science-environment-23317368)

A change in the frequency of earthquakes may foretell explosive volcanic eruptions, according to a new study.

The seismic activity changes from steady drum beats to increasingly rapid successions of tremors.

These blend into continuous noise which silences just before explosion.

The study of tremors in the lead up to the 2009 eruption of Redoubt, a volcano in Alaska, appears in Journal of Volcanology and Geothermal Research.

Those quakes continuously rose in pitch like a volcanic glissando - a musical glide from one pitch to another.

Subterranean magma plumbing systems sit beneath volcanoes and feed pressurised molten rock toward the surface before eruptions.

As the magma flows through deep conduits and cracks, it generates small seismic tremors and earthquakes.

Scientists have noted earthquakes preceding volcanic eruptions before, for example drumbeat earthquakes were the first sign of renewed magmatic activity in Mount St Helens in April 2005.

But the new analysis of Alaska's Redoubt volcano shows that the tremor glided to higher frequencies and then stopped abruptly less than a minute before eruption.

grapes
2013-Jul-16, 06:08 PM
I'm a gonna guess that every volcano is its own instrument, and plays its own music. :)

Ara Pacis
2013-Jul-16, 06:47 PM
And I thought it was merely dramatic license that the music or tone amps up and then cuts out to a moment of silence right before the big bada-boom.

NEOWatcher
2013-Jul-16, 06:55 PM
Is that anything like the sound of pouring soda into a glass (http://www.youtube.com/watch?v=oXFrGRINFIU) until it erupts?
(Its amazing what people take the time to put on youtube)

dgavin
2013-Jul-18, 07:32 PM
But the new analysis of Alaska's Redoubt volcano shows that the tremor glided to higher frequencies and then stopped abruptly less than a minute before eruption.


That would seem to indicate the the magma reached a solid plug in the volcanic chimney, and that after that point, it may only take a few minutes of pressure to build to an explosive eruption?

Neat article, thanks Swift!