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Earth's cry for help? Volcanoes scream before they explode

The new findings come from research conducted during the 2009 eruption of Alaska’s Redoubt volcano.

seismic screamEnlarge
Researchers have discovered that volcanoes let out a 'seismic scream' before they erupt, adding to findings about how and when they explode. (PABLO SPENCER/AFP/Getty Images)

Volcanoes have feelings too. That's according to a new study that claims that volcanoes "scream" before they erupt.

We'd like to imagine that their howls are the Earth crying out but what seismologists have called the "the seismic scream" may just be just the harmony of microquakes before the big one.

The new findings come from research conducted during the 2009 eruption of Alaska’s Redoubt volcano.

In the days leading up to the eruption, scientists at Stanford found that that a series of small earthquakes that preceded the initial explosions were perfectly spaced out like the "tooth of a comb," according to Wired.

These happened at rates of six per second until it was a simple hum.

"Because there's less time between each earthquake, there's not enough time to build up enough pressure for a bigger one. After the frequency glides up to a ridiculously high frequency, it pauses and then it explodes," said Alicia Hotovec-Ellis, a doctoral student involved in the study, from the University of Washington.

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Though this pattern had been seen before, the mini eruptions were faster than ever, creating an increasing "scream."

Building pressure is key in explaining this cry from the bowels of the Earth. The sudden pressure change before a volcano, caused by crystallizing magma blocking the spout, may result in the particular sound.

Magma pushing through that which has already hardened naturally whistles and howls.

Shortly before a volcano blows, it suddenly goes silent. This could be the moment before the magma breaks through the surface and races to the top.

The research adds to the understanding of how volcanoes erupt and the sequence of events before the initial explosion.

The findings were published this week in Journal of Volcanology and Geothermal Research.

http://www.globalpost.com/dispatch/news/science/130715/earths-cry-help-volcanoes-scream-they-explode