Electronic Supplement to
Listening to the 2011 Magnitude 9.0 Tohoku-Oki, Japan, Earthquake

by Zhigang Peng, Chastity Aiken, Debi Kilb, David R. Shelly, Bogdan Enescu

QuickTime Movies

Movie S1 [Japan_03112011_MYG004.mov; 2.4 MB]. Example of near-field strong motion recordings at the K-Net station MYG004 during the 2011 Mw 9.0 Tohoku-Oki earthquake. The seismogram trace changes from light to dark as a time indicator progression line (vertical pink line) moves from left to right in the video. (Top) North-component acceleration seismogram. (Middle) 30 Hz high-pass-filtered seismogram. (Bottom) The spectrogram of the North-component seismogram. The signal associated with the highest ground acceleration at ~ 90 s has higher frequency content that those at other times. A 0.5 Hz high-pass filter is applied before computing the spectrogram in order to reduce the high-frequency artifact generated from applying a short-time-window Fourier transform to a long-period signals (Peng et al., SRL, 2011). The sound is generated by speeding up the seismic data by 50 times.

Movie S2 [Japan_03112011_MYG003.mov; 2.5 MB]. Example of near-field strong motion recordings at the K-Net station MYG003 during the 2011 Mw 9.0 Tohoku-Oki earthquake. Other symbols and notations are the same as Movie S1. The high-frequency burst at station MYG004 at ~90 s was not recorded at this station.

Movie S3 [Japan_03112011_HTAH.mov; 9 MB]. Example of the mainshock and early aftershock recordings during the 2011 Mw 9.0 Tohoku-Oki earthquake. (Top) Vertical-component velocity seismogram recorded at Hi-net station HATH. (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 100 times.

Movie S4 [Japan_03112011_PKD.mov; 4.9 MB]. Example of tremor around the Parkfield-Cholame section of the San Andreas Fault triggered that occurred during the passage of teleseismic waves from the 2011 Mw 9.0 Tohoku-Oki earthquake. (Top) Broadband transverse-component seismogram recorded at the station PKD. The two vertical lines mark the approximate arrival times of the Pand Swaves. (Middle) 5 Hz high-pass-filtered transverse-component seismogram showing the triggered tremor signals during the teleseismic Sand surface waves. (Bottom) Spectrogram of the transverse-component seismogram from station PKD. The triggered tremor signals can be identified by the narrow vertical bands indicating richness in high-frequency energy. The sound is generated by speeding up the seismic data by 100 times.

Movie S5 [Japan_03112011_MHC.mov; 5.1 MB]. Animation of the transverse-component seismogram recorded at the station MHC along the central section of the Calaveras fault. There are no clear tremor-like signals during the teleseismic Sand surface waves. However, two microearthquakes occurred around 2900 s after the mainshock origin time.

Movie S6 [Tohoku-Oki_Shelly_PKD.mov; 6.7 MB]. Example of triggered tremor during the 2011 Mw 9.0 Tohoku-Oki earthquake. The top panel shows a cross-section view along and parallel to the Parkfield-Cholame section of the San Andreas Fault. The blue dots mark the hypocenters of regular earthquakes, and the small black plus symbols show tremor family source locations. When activity is detected in each family, the source location lights up as a solid red circle. This circle slowly fades to yellow, green and blue while shrinking in size and finally disappearing, to assist the eye in tracking migration. Lower panels show velocity seismograms recorded near Parkfield, filtered 4-9 Hz showing mostly local energy (upper) and unfiltered broadband station PAGB vertical (black) and transverse (blue) in the lowermost panel, showing mostly energy from the distant earthquake. The sound is generated by speeding up the seismic data by 100 times.

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