Tohoku earthquake 2011
(2011) ·
Tohoku Earthquake 2011 (from WRAB)
Tohoku Earthquake 2011 (from WRAB) [5:51 · download]


This is the sound of the Earth's crust tearing apart during the devastating magnitude 9.0 earthquake that struck off the northeast coast of Japan on March 11, 2011.[1]

The sounds were collected at a seismic listening post deep in the Australian outback,[2] about 6,900km (4,100 miles) from the epicenter. To make the Earth's natural low-frequency seismic vibrations audible in this recording, I speeded them up by a factor of 500. The nearly six minute duration of this recording thus spans just over two days in real Earth time.

The recording begins on March 10 at about 16:00 GMT, a day before the Japan earthquake. About 10 seconds into the recording, a loud bang signifies the arrival of seismic waves from a moderate quake (magnitude 6.5) in the Bali Sea, about 2,400km (about 1,450 miles) from the recording station. Earthquakes of this size are commonplace, occurring somewhere on the planet once every few days.[3] For several seconds (almost an hour in Earth time) you can hear the echoes from this particular earthquake reverberating through the earth's crust, until they finally fade into the background noise. (Please note that I haven't added any echo or reverb effects to this recording; the Earth itself is a brilliant echo chamber.)

For the next minute and a half, allow your ears to settle in to the soothing rushhh of the ever-present background noise — the planet-wide vibration caused by ocean waves pounding on coastlines and continental shelves the world over. Occasionally against this backdrop, you'll hear the faraway tick or pop of a small earthquake occurring somewhere in the world.

Map showing locations of aftershocks following the earthquake. Image courtesy of USGS.

Suddenly, everything changes. Without warning, at about 1:40 into this recording, a thunderclap announces the arrival in Australia of the first seismic waves from the Japan earthquake. (The tsunamis generated by the earthquake are not audible in this recording.) For hours afterwards (the remainder of this recording), the Earth booms and crackles from hundreds of aftershocks, as the crust fitfully readjusts to the gigantic dislocation brought about by the main earthquake. Gradually the aftershocks dissipate, eventually slipping away into the ever-present oceanic background. The damage done, Earth will return to its normal state of uneasy equilibrium.


For a summary of scientific information about this earthquake, see ”Magnitude 9.0 – NEAR THE EAST COAST OF HONSHU, JAPAN
Recorded at IDA station WRAB, Tennant Creek, Australia. Three-component broadband seismometer, sampled at 20Hz. [Project IDA currently operates a global network of broadband and very broadband seismometers for the IRIS Consortium. Project IDA is based at the Cecil and Ida Green Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego:]
See "Earthquake Facts and Statistics" by the USGS.