microrobert
07-17-2013, 12:28 PM
Alaska's Redoubt Volcano 'Screamed' Before Exploding
Earthquakes can often signal an impending volcanic eruption, and sometimes before a mountain blows its lid, seismologists detect a continuous, rhythmic series of quakes known as a harmonic tremor.
One after the other, tiny temblors originate beneath a volcano, typically accompanied by a rumble that's at such a low frequency, humans would not be able to hear it. But the harmonic tremor that preceded the March 2009 eruption of Alaska's Mount Redoubt made the volcano "scream," the frequency got so high, researchers say.
Alaska's Redoubt Volcano 'Screamed' Before Exploding | LiveScience (http://www.livescience.com/38209-alaska-redoubt-volcano-screams.html#sthash.6X2Wi1tE.dpuf)
Earthquakes can often signal an impending volcanic eruption, and sometimes before a mountain blows its lid, seismologists detect a continuous, rhythmic series of quakes known as a harmonic tremor.
One after the other, tiny temblors originate beneath a volcano, typically accompanied by a rumble that's at such a low frequency, humans would not be able to hear it. But the harmonic tremor that preceded the March 2009 eruption of Alaska's Mount Redoubt made the volcano "scream," the frequency got so high, researchers say.
Alaska's Redoubt Volcano 'Screamed' Before Exploding | LiveScience (http://www.livescience.com/38209-alaska-redoubt-volcano-screams.html#sthash.6X2Wi1tE.dpuf)