On the web: Shake, rattle and also roll: What does an earthquake sound like?

by Timothy Oleson Monday, July 23, 2012


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Using a new technique, researchers have actually boosted seismic waves (top) from the 2011 Tohoku earthquake come frequencies (bottom) within the audible selection for humans. Georgia institute of Technology


The sounds us associate v earthquakes tend to be those inducedaboveground. Low-pitched rumbles, rattling windows and car alarms mightbe heard during tiny temblors, while much more terrifying sounds like thecrumbling the concrete and also the cacophony of human being trying to with safetysometimes accompany big earthquakes. Yet what walk an earthquakeitself sound like, together rock grinds against rock in a rupturing fault andlarge amounts of power are released? thanks to some recent efforts, wemay be starting to acquire an idea.

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In truth, it is difficult to know what earthquakes underground soundlike because typical seismic waves have actually frequencies below the audiblerange for humans, which is in between 20 and also 20,000 Hertz. Now, however, agroup of researchers has given voice to one seismic monster: the March11, 2011, magnitude-9.0 Tohoku earthquake that rocked Japan and also wasdetected top top seismometers worldwide.

By converting seismic data indigenous instruments roughly the earth to soundfiles and also then play the recordings ago at faster-than-real-timespeeds, the researchers raised the seismic frequencies into the audiblerange. The an approach also condenses the signal so that procedures thatoccurred over numerous minutes or hours can be heard on lot shortertimescales. Depending upon where the seismometers that recorded aparticular dataset were located, the resulting sound of the key shockand the aftershocks resemble every little thing from booming explosions todistant thunderclaps and also gentle rainfall come the sound the furniture beingrolled across a hardwood floor.

The researchers, led in part by seismologist Zhigang Peng the GeorgiaTech, detailed their an approach recently in Seismological ResearchLetters. Sample sound papers are also posted online(http://geophysics.eas.gatech.edu/people/zpeng/Japan_20110311/index.html)for all to enjoy.

Beyond the novelty of “hearing” earthquakes, make seismic activityaudible offer other crucial purposes, follow to Peng. Because that example,it could be useful to researchers studying the physics and also triggeringbehavior the earthquakes, or to scientific research educators teaching generalaudiences about the science behind huge temblors. “People space able tohear pitch and amplitude transforms while watching seismic frequencychanges. Audiences deserve to relate the earthquake signal to familiar soundssuch as thunder, popcorn popping and fireworks,” Peng stated in a pressrelease.

In a separate effort, resourceful YouTube user has come increase withanother way to audibilize earthquakes: assembling the global catalogof earthquakes greater than magnitude-4.5 in 2011 to produce a kind oftime-lapse audio-visual seismic collage. The method is similar to oneused for educational purposes in the 1990s by the SmithsonianInstitution and also others. Yet now, it’s been updated because that the web Age.The video, licensed has been granted “World Earthquakes 2011 visualization Map,” wasposted to the website by user StoryMonoroch in January and by mid-May hadalready amassed an ext than 620,000 views.

Each that the more than 9,000 events, traction from the U.S. GeologicalSurvey’s earthquakearchive, was assigned anaudible ton — sounding choose a computerized thump — the volume andpitch of i m sorry were based on the earthquake’s magnitude and also depth,respectively. Together 2011 zips by over the food of 6 minutes, theconstant drone of small events is periodically punctuated v loudermagnitude-7.0 and greater earthquakes.

In addition to the thump, each quake is projected ~ above a human being map as ayellow dot surrounded by a red circle of varying size, representing thehypocenter and also magnitude, respectively. The visual screen provides auseful accompaniment come the audio, clearly demarcating the plateboundaries and also other tectonically active areas whereby the substantial majorityof seismic task is concentrated.

If you room not interested in sitting through the entire year’s recap,make sure to at the very least listen previous the 1:50-mark in the video. This iswhere the collage gets yes, really interesting. A pair of huge foreshocksimmediately precede a jolting eight that wake up seemingly out of nowhereon, you guessed it, march 11. The magnitude-9.0 blast sets turn off a cascadeof rapid-fire aftershocks that — if your speakers are turned increase —might make you feel choose you stepped onto the set of “Tron.” Alsointeresting is the notable rise in the price of worldwide seismicity,albeit conquered by the aftershocks concentrated near Japan, in theweeks complying with the Tohoku quake.

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Not surprisingly, created descriptions perform not execute these projects justice.And while no is most likely to rock your world, precise orfiguratively, the videos carry out make for a few fascinating and also awe-inspiringlistens. Simply be careful: You could want to turn down her computer’svolume first.