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 earthquake noise sounds like a scream before eruption when the seismometer data are speeded up sixty times to make them audible."

Full story at link, and in the story is a link to the audio.

Brian

• Volcanic 'scream' precedes explosive eruptions