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Hear the soundtrack of a super-quake

This recording of the 2011 Japan earthquake was taken near the Japanese coastline between Tokyo and the Fukushima nuclear reactor site. Georgia Tech researchers converted the seismic waves into audio files.




Researchers from Georgia Tech suggest that the best way to visualize the seismic effects of last year's Japan earthquake is with your ears — and they've put together three "audifications" to demonstrate.

One recording is based on seismometer readings taken on March 11, 2011, along the Japanese coastline between Tokyo and the hard-hit Fukushima nuclear complex. The audio starts with a bang — the magnitude-9.0 shock — and continues with the pounding noise of aftershocks that sound like a bull knocking over shelves in a china shop.


Readings from seismometers that were place about 90 miles away from the quake's epicenter reveal a double-barreled bang. That suggests there were "at least two patches of high-frequency radiation from the mainshock rupture," the researchers note.

A third clip is based on readings from California. The Japan quake sparked deep rumblings in the San Andreas Fault, which begin with a sound like distant thunder, and then continue with a crackle that represents "induced tremor activity at the fault," the Georgia Tech team says.

The audio was created by taking the seismic signals, which are typically detected in the 0.01 to 100 Hz frequency range, and speeding the soundtrack by a factor of 50 to 100 times. That brings the sound into the audible range of 20 Hz to 20 kHz, and crunches hours' worth of data into less than a minute of audio.

This recording was taken about 90 miles from the Japanese earthquake's epicenter. There are two distinct sound waves. Both are caused by the main shock. A "pop" is heard 90 seconds (in actual time) after the main event. This pop wasn't recorded at any other nearby stations, leading Georgia Tech's Zhigang Peng to believe that the ground shifted immediately under the measuring station.

In this recording of the 2011 Japanese earthquake, taken from measurements in California, the quake created subtle movements deep in the San Andreas Fault. The initial noise, which sounds like distant thunder, corresponds with the Japanese main shock. Afterwards, a continuous high-pitch sound, similar to rainfall that turns on and off, represents induced tremor activity at the fault.

In these YouTube videos, the seismic data is also displayed on a graph.

"By combining seismic auditory and visual information, static 'snapshots' of earthquake data come to life," Georgia Tech's Zhigang Peng and his colleagues write in the March-April edition of Seismological Research Letters. "In addition, this approach allows the audience to relate seismic signals generated by earthquakes to familiar sounds such as thunder, popcorn popping, rattlesnakes, gunshots, firecrackers, etc."

The researchers say that seismic audifications can make it easier to explain the concept of distant quake triggering to general audiences, and that they also provide a tool for experts to identify and understand such seismic signals in other regions. What do you think? Do these clips give you a better feel for how seismic events get started and keep rattling on?

One year after the disaster in Japan:


Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.