Skip to main content

Volume 56 Supplement 8

Special Issue: IUGG Hagiwara Symposium

Seismological evidence for the brittle-ductile interaction hypothesis on earthquake loading


We extended the analyses of temporal variation of coda Q−1 and seismicity by Jin and Aki (1989, 1993) for central and southern California to year 2003. We use the relative frequency N(M c ) of earthquakes in a certain magnitude range around M c characteristic to a seismic region to quantify the seismicity. The cross-correlation function between coda Q−1 and N(M c ) is calculated using a 10-year moving time window. The correlation coefficient for the entire period of about 60 years is peaked at the zero-time shift with the value close to 0.8 for both regions. We found, however, the simultaneous correlation is disturbed before major earthquakes. The disturbance is, consistently, a delay in the change of coda Q−1 relative to that of N(M c ) before the occurrence of a major earthquake. We attribute the temporal change in coda Q−1 to fractures in the ductile part of the lithosphere and that in N(M c ) to the response of the brittle part to the ductile fracture. We believe that M c characteristic to a seismic region is originated from a characteristic size of fractures in the ductile zone of the lithosphere. The observed delay of coda Q−1 change relative to N(M c ) before a major earthquake can be explained simply by the strain energy stored in the brittle part of lithosphere reaching a saturation limit and starting to flow back to the ductile part.


  • Aki, K., Scale dependence in earthquake processes and seismogenic structure, PAGEOPH, 157 (2000), 2249–2258, 2000.

    Article  Google Scholar 

  • Aki, K., A new view of earthquake and volcano precursors, Earth Planets Space, 56, this issue, 689–713, 2004.

    Article  Google Scholar 

  • Aki, K. and B. Chouet, Origin of coda waves: Source, attenuation, and scattering effects, J. Geophys. Res., 80, 3322–3342. ANSS catalog,, 1975.

    Article  Google Scholar 

  • Chouet, B., Temporal variation in the attenuation of earthquake coda near Stone Canyon, California, Geophys. Res. Lett., 6, 143–146, 1979.

    Article  Google Scholar 

  • Hiramatsu, Y., N. Hayashi, M. Furumoto, and H. Katao, Temporal change in coda Q-1 and b-value due to the static stress change associated with the 1995 Hyoko-ken Nanbu earthquake, J. Geophys. Res., 105, 1641–1651, 2000.

    Google Scholar 

  • Jin, A. and K. Aki, Temporal change in coda Q before the Tangshan earthquake of 1976 and the Haicheng earthquake of 1975, J. Geophys. Res., 91, 665–673, 1986.

    Article  Google Scholar 

  • Jin, A. and K. Aki, Spatial and temporal correlation between coda Q-1 and seismicity and its physical mechanism, J, Geophys. Res., 94, 14041–14059, 1989.

    Article  Google Scholar 

  • Jin, A. and K. Aki, Temporal correlation between coda Q−1 and seismicity—Evidence for a structure unit in the brittle-ductile transition zone, J. Geodynamics, 17, 95–119, 1993.

    Article  Google Scholar 

  • Li, Q. and B. Chen, Spatial and temporal change of b-value before the Tangshan Earthquake of 1976, J. Geophys., 21, 89–96 (in Chinese with English abstract). SCEC catalog,, 1981.

    Google Scholar 

  • Tsukuda, T., Coda Q before and after the 1983 Misasa earthquake of M6.2, Tottori Pref. Japan, PAGEOPH, 128, 261–280, 1988.

    Article  Google Scholar 

  • Zaliapin, I., A. Gabrielov, and V. Keilis-Borok, Multiscale trend analysis, submitted to Fractals, 2003.

    Google Scholar 

  • Zaliapin, I., A. Jin, Z. Liu, and K. Aki, Temporal (un)correlations between coda Q and seismicity—a multiscale trend analysis, PAGEOPH, 2004 (in press).

    Google Scholar 

  • Zoback, M. D. and M. L. Zoback, State of stress in the Earth’s lithosphere, International Handbook of Earthquake and Engineering Seismology, Academic press, Amsterdam, 559–568, 2002

    Chapter  Google Scholar 

Download references

Author information

Authors and Affiliations


Corresponding author

Correspondence to Anshu Jin.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Jin, A., Aki, K., Liu, Z. et al. Seismological evidence for the brittle-ductile interaction hypothesis on earthquake loading. Earth Planet Sp 56, 823–830 (2004).

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

Key words

  • Coda Q
  • characteristic magnitude M c
  • seismogenic zone
  • plate driving earthquake loading
  • brittle-ductile transition zone