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Some volcanoes ‘scream’ at ever-higher pitches until they blow their tops

By Guest PostJuly 31, 2013Sciencealaska, alicia hotovec ellis, arenal volcano, costa rica, crust, cycle per second, earth, eric dunham, frictional faulting model, harmonic tremor, joan gomberg, john vidale, ksenia dmitrieva, redoubt volcano, small earthquakes, soufriere hills volcano, stanford university, stephanie prejean, tremor mechanism, U.S. Geological Survey, university of washington, volcanic eruption, volcanoes

It is not unusual for swarms of small earthquakes to precede a volcanic eruption. They can reach a point of such rapid succession that they create a signal called harmonic tremor that resembles sound made by various types of musical instruments, though at frequencies much lower than humans can hear.

A new analysis of an eruption sequence at Alaska’s Redoubt Volcano in March 2009 shows that the harmonic tremor glided to substantially higher frequencies and then stopped abruptly just before six of the eruptions, five of them coming in succession. (more…)

One Year Later: Japan Quake, Tsunami a Cautionary Tale for Pacific Northwest

By Guest PostMarch 8, 2012Environment, Generalalki, british columbia, cascadia subduction zone, earthquakes, hokkaido university, Japan, jody bourgeois, john vidale, long beach peninsula, magnitude 9, northern california, ocean shores, one year anniversary, oregon, pacific northwest, prediction, puget sound, sapporo, seattle fault, seismometer readings, sunday, tohoku earthquake, tsunami, tsunami evacuation, united states, university of washington, Washington

Sunday marks the one-year anniversary of the great Tohoku earthquake and tsunami that devastated Japan, killing more than 16,000 people and causing billions of dollars in damage.

University of Washington scientists say the event has some important lessons for the Pacific Northwest – most notably, not that a similar event can happen here but that it WILL happen here, and that this region is still much less prepared than Japan was a year ago. (more…)

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Some volcanoes ‘scream’ at ever-higher pitches until they blow their tops

One Year Later: Japan Quake, Tsunami a Cautionary Tale for Pacific Northwest