Earthquake Sound of the Mw9.0 Tohoku-Oki, Japan earthquake (Zhigang Peng)

by Zhigang Peng


This webpage contains earthquake "sounds" created from seismic recordings around the world generated by the 2011/03/11 Mw9.0 Tohoku-Oki, Japan earthquake. They provide a unique way for us to listen to the vibration of the Earth that is otherwise inaudible to us, and to decipher the complicated earthquake physics and triggering processes.

Note: 1. The material developed in this website is partially supported by the National Science Foundation's CAREER program EAR-0956051 .

2. The seismic data used in this website are downloaded from the IRIS , NIED in Japan , and various regional and local seismic networks.

3. I have been working closely with David Simpson, the IRIS president, and Debi Kilb, a researcher at UCSD , and many researchers and students on this topic. If you would like to use these sound tracks, I would appreciate if you could put proper acklowledgement and cite the following papers: Peng, Z., C. Aiken*, D. Kilb, D. Shelly, B. Enescu (2012), Listening to the 2011 magnitude 9.0 Tohoku-Oki, Japan earthquake, Seismol. Res. Lett., 83(2), 287-293, doi: 10.1785/gssrl.83.2.287. , and Kilb, D., Z. Peng, D. Simpson, A. Michael and M. Fisher* (2012), Listen, watch, learn: SeisSound video products, Seismol. Res. Lett., 83(2), 281-286, doi: 10.1785/gssrl.83.2.281.

Part I: Sounds/Animations related to the M9.0 Tohoku-Oki, Japan earthquake

Part II: Matlab Code to Convert Seismic Data in SAC Format to .wav or .mov Format

Part III: Related Links


Near-field strong motion recording at K-Net station MYG004

  • The Mw9.0 Tohoku-Oki, Japan earthquake was recorded by two of the world's densest strong motion seismic networks, namely the K-Net and the Kik-Net. The example showing here was recorded by the K-Net station MYG004, which has the highest peak ground acceleration (PGA) of up to 3 g. This near-field recording show clearly two groups of ground motion, suggesting at least two patches of high-frequency radiation from the mainshock rupture. The highest PGA occurred at around 90 s, and the frequency and sound is quite different than the rest group, indicating that it was created either by a very shallow source beneath the station, or by local site effects or topographic amplifications.
  • Japan_20110311/MYG004.NS.SAC.wav earthquake sound by speeding up 30 times from strong motion recording at station MYG004.
  • Japan_03112011_MYG004.mov Animation with sound showing the strong-ground motion recording at station MYG004. The three panels are the original data, 30-Hz high-pass-filtered and the spectrogram at the N-S component, respectively.

Early aftershocks of the 2011 Mw9.0 Tohoku-Oki, Japan earthquake recorded at Hi-Net station HTAH

  • This example shows the sounds from the Tohoku-Oki mainshock and early aftershocks within the first hour. We amplify the sounds by 50 times so that we can hear the aftershock signals clearly. The initial blast of sound is the 9.0 mainshock. As the earth's plates slipped dozens of meters into new positions, aftershocks occurred. They are indicated by "pop" noises immediately following the mainshock sound. You may want turn off the volume slightly. (Top) Vertical-component velocity seismogram recorded at Hi-net station HTAH. (Middle) 20 Hz high-pass-filtered envelope functions highlighting the mainshock and early aftershock signals. The envelope function is smoothed with a half width of 50 data points and is in base 10 logarithmic scale. The black lines marked the predicted P-wave arrivals of aftershocks around the mainshock slip region as listed in the Japan Meteorological Agency (JMA) earthquake catalog. (Bottom) The spectrogram. The sound is generated by speeding up the seismic data by 50 or 100 times.
  • Japan_20110311/HTAH.EHZ.SAC.wav earthquake sound by speeding up 100 times from short-period recording at station HTAH.
  • Japan_03112011_HTAH.mov Animation with sound showing the mainshock and early aftershocks of the Tohoku-Oki sequence (speed-up 100 times).
  • Japan_03112011_HTAH_50_times.mov Animation with sound showing the mainshock and early aftershocks of the Tohoku-Oki sequence (speed-up 50 times).

Triggered tremor in southwest Japan recorded at F-Net station TSA

  • The Mw9.0 Tohoku-Oki, Japan earthquake triggered tremor activity in southwest Japan. In this example, we use th F-Net broadband station TSA to show the long-period teleseismic signals. Because this instrument is slightly clipped during the surface wave, we use a nearby Hi-Net station KWBH to show the high-frequency signals and generate the sound. As shown in the image/animation, the signal during the surface wave has much higher frequency than the P wave, suggesting that they are generated by sources near the station. Based on previous studies by other research group and our initial inspection of nearby stations we interprete those high-frequency signals as deep non-volcanic tremor on the southwest Japan subduction zone triggered by the mainshock. For additional information, please read the Miyazawa and Brodsky (JGR, 2008) and Miyazawa et al. (EPS, 2008 ) papers.
  • Japan_20110311/BO.TSA.BHT.SAC.wav earthquake sound by speeding up 100 times from Hi-Net station KWBH.
  • Japan_03112011_TSA.mov Animation with sound showing the broadband signal at the F-Net station TSA, and the high-frequency signal recorded at the Hi-Net station KWBH. The three panels are the original data, 5-Hz high-pass-filtered and the spectrogram, respectively.

Triggered tremor in southern Central Range, Taiwan recorded at BATS station TW.TPUB

  • The Mw9.0 Tohoku-Oki, Japan earthquake triggered clear tremor activity in the central Range in Taiwan. In this example, we use th BATS broadband station TPUB to show the long-period teleseismic signals, and high-frequency triggered tremor signals. We can hear/see two distinct groups in the P wave, and high-frequency signals that started around the S wave, and became further intensified around the subsequent Love and Rayleigh waves. Interestingly, the tremor appears to turn off while the surface wave continues. For more information, please refer to the following papers/manuscript ( Peng and Chao, GJI, 2008i ; Tang et al., GRL, 2010 ; and Chao et al., GJI, submitted) .
  • Japan_20110311/TW.TPUB.BHT.SAC.wav earthquake sound by speeding up 100 times from BATS station TPUB.
  • Japan_03112011_TPUB.mov Animation with sound showing the broadband and high-frequency tremor signals at the BATS station TPUB. The three panels are the original data, 5-Hz high-pass-filtered and the spectrogram, respectively.

Triggered microearthquakes near Beijing, China recorded at IRIS station IC.BJT

  • The Mw9.0 Tohoku-Oki, Japan earthquake also triggered microearthquake activity near Beijing, China. In this example, we use the IRIS broadband station IC.BJT to show the long-period teleseismic signals, and high-frequency triggered earthquake signals. We can hear/see two distinct groups in the P wave, and high-frequency signals in the first few cycles of the long-period surface waves. For more information, please refer to the following papers ( Peng et al., EPS, 2010 ; Jiang et al., BSSA, 2010 ; and Wu et al., GJI, 2011 ).
  • Japan_20110311/IC.BJT.BHN.SAC.wav earthquake sound by speeding up 100 times from IRIS station IC.BJT.
  • Japan_03112011_BJT.mov Animation with sound showing the broadband and high-frequency earthquake signals at the IRIS station IC.BJT. The three panels are the original data, 5-Hz high-pass-filtered and the spectrogram, respectively.

Triggered tremor along the Parkfield-Cholame section of the San Andreas Fault recorded at station BK.PKD

  • The Mw9.0 Tohoku-Oki, Japan earthquake triggered clear tremor activity along the Parkfield-Cholame section of the San Andreas Fault. In this example, we use the Berkeley broadband station BK.PKD to show the long-period teleseismic signals, and high-frequency triggered tremor signals. The tremor signals showed right at the time of the S wave, and became further intensified and modulated by the long-period Love and Rayleigh waves. hear/see two distinct groups in the P wave, and high-frequency signals in the first few cycles of the long-period surface waves. For more information, please refer to the following papers ( Peng et al., GRL, 2008 ; Peng et al., JGR, 2009 ; and Peng et al., GRL, 2010 ).
  • Japan_20110311/PKD.HHT.SAC.wav Earthquake sound by speeding up 100 times from IRIS station BK.PKD.
  • Japan_03112011_PKD.mov Animation with sound showing the broadband and high-frequency earthquake signals at the Berkeley station BK.PKD. The three panels are the original data, 5-Hz high-pass-filtered and the spectrogram, respectively.
  • Japan_20110311/PKD.HHT.SAC.vco.wav Earthquake sound by speeding up 100 times from IRIS station BK.PKD. This version contains not only the sounds from the relatively high-frequency signals, but also the sounds from the long-period signals (i.e., teleseismic waves) from Japan. We use a technique called frequency modulation to map those long-period signals into audible range.
  • Japan_03112011_PKD_vco.mov Animation with sound showing the broadband and high-frequency earthquake signals at the Berkeley station BK.PKD. The three panels are the original data, 5-Hz high-pass-filtered and the spectrogram, respectively. Again, the version contains not only the sounds from the relatively high-frequency signals, but also the sounds from the long-period signals (i.e., teleseismic waves) from Japan. You can hear very nice correlations between the high-pitch signals (triggered tremor at California) and long-period signals from japan.
  • PFtrigTohoku_Shelly_sound.mov Animation with s ound showing the location of tremor along the San Andreas Fault triggered by the Tohoku-Oki, Japan event. The movie was made by Dave Shelly at USGS , and the sound was added later by Zhigang Peng .

Conversion from .SAC to .WAV Format

  • Below is a sample matlab script that can be used to convert the seismic data in SAC format to .WAV format. This simple matlab script requires the fget_sac.m subroutine, which is in the MatSAC package . For more information about how to use the fget_sac.m, please visit my SAC tutorial .
  • Matlab code sac2wav.m .
  • Example input SAC file BP.GHIB.DP1.SAC , the vertical component seismogram generated by the 2002 Mw7.8 Denali Fault earthquake, and recorded at the borehole station GHIB around the Parkfield section of the San Andreas Fault in Central California (e.g., Peng et al. (GRL, 2008), Peng et al. (JGR, 2009)).
  • Example output .WAV file BP.GHIB.DP1.SAC.wav .
  • Default parameters: sacfile = 'BP.GHIB.DP1.SAC'; speed_factor = 500; scale = 1.2; t1 = 0; t2 = 2000.

Conversion from .SAC to .MOV Format

  • We are in the process of developing simple tools that allow us to create animations (i.e., images plus sounds) based on seismograms (Fischer et al., 2010). The basic idea is described in the following simple dialgram:
  • See below for an animation generated for the tremor around Parkfield triggered by the 2002 Denali Fault earthquake.
  • PKD_Denali_Triggered_Tremor_update.mov (10 MB)


Last updated by Zhigang Peng Wed Mar 7 08:47:34 EST 2012