Shallow Dynamic Overshoot and Energetic Deep Rupture in the 2011 Mw 9.0 Tohoku-Oki Earthquake

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Science  17 Jun 2011:
Vol. 332, Issue 6036, pp. 1426-1429
DOI: 10.1126/science.1207020
  • Fig. 1

    The total slip distribution (left) and snapshots of the slip-rate distribution at six different times (right). Blue/white (0309), red/white (MS), and orange/white circles (0312 and 0314) show focal mechanisms of the foreshock on 9 March (Mw 7.3), the mainshock, and two aftershocks with opposite mechanism on 12 March (Mw 6.5) and 14 March (Mw 6.1), connected to their epicenters with gray lines. Circles are epicenters determined by the Japan Meteorological Agency. Smaller red circles are the mainshock (star) and aftershocks; smaller blue circles are the largest foreshock (star) and foreshocks. The fault plane is 440 by 220 km. A blue curve in the inset shows the global-moment rate function, which is the moment rate observed in the far-field perpendicular to the fault.

  • Fig. 2

    (Left) Strong motion records high-pass filtered above 10 Hz at nine KiK-net stations of the National Research Institute for Earth Science and Disaster Prevention distributed along the rupture. The maximum amplitude in centimeters per second per second is shown at the top-right of each waveform (Right) Mainshock slip distribution. The S-wave arrival times from several source locations, denoted with colored stars and with time after the rupture initiation also shown, are plotted on the waveforms with length inversely proportional to the source-station distance.

  • Fig. 3

    (Left) Mainshock and eGf broadband seismograms at GSN station KEV. (Right) Spectra of P-wave train for mainshock seismograms after deconvolving different eGf events. The close correspondence of the corrected spectra indicates that our results are robust with respect to the assumed eGf; however, the moment spectra of the mainshock appears to be missing the lowest-frequency components. We extrapolated the spectra to low frequencies, as shown by the dashed lines. This is a source of uncertainty, but the amount of energy involved in the extrapolation is 18% on average, for all stations and eGf corrections.

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  • Shallow Dynamic Overshoot and Energetic Deep Rupture in the 2011 Mw 9.0 Tohoku-Oki Earthquake

    Satoshi Ide, Annemarie Baltay, Gregory C. Beroza

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