Researchers Find Some Volcanoes 'Scream' At Increasing Pitches Until They Blow 59
vinces99 writes "Swarms of small earthquakes often precede a volcanic eruption. They can reach such rapid succession that they create a "harmonic tremor" that resembles sound made by some musical instruments. A new analysis of an eruption sequence at Alaska's Redoubt Volcano in March 2009 shows the harmonic tremor glided to substantially higher frequencies and then stopped abruptly just before six of the eruptions. Scientists at the U.S. Geological Survey's Alaska Volcano Observatory have dubbed the highest-frequency harmonic tremor at Redoubt Volcano 'the screams' because the episodes reach such high pitch compared with a 1-to-5 hertz starting point. Alicia Hotovec-Ellis, a University of Washington doctoral student in Earth and space sciences and an author of two papers examining the phenomenon, has created a 10-second recording and a one-minute recording that provides a 60-times faster representation of harmonic tremor and small earthquakes."
Thetans ... (Score:1, Informative)
It's the thetans getting ready to take a massive shit in Tom Cruise's mouth and fill him with even more blessings.
Re:harmonic tremor, screaming? (Score:5, Informative)
She documented the rising tremor frequency, starting at about 1 hertz (or cycle per second) and gliding upward to about 30 hertz. In humans, the audible frequency range starts at about 20 hertz, but a person lying on the ground directly above the magma conduit might be able to hear the harmonic tremor when it reaches its highest point (it is not an activity she would advise, since the tremor is closely followed by an explosion).
However this is slashdot so no need to RTFA, just carry on with redundant questions veiled in the shape of a seemingly innocuous post.