pure and applied geophysics

, Volume 126, Issue 2–4, pp 447–463 | Cite as

Downward migration of seismic activity prior to some great shallow earthquakes in Japanese subduction zones—a possible intermediateterm precursor

  • Kiyoo Mogi
Seismologic and Geodetic Precursors


Before the 1944 Tonankai earthquake along the Nankai Trough, seismic activity increased in the shallow depths, and then the activity gradually migrated downwards. When it reached its limit (a depth of approximatelty 70 km), the main shock occurred. Several deep earthquakes, including one ofM5.3, occurred several months prior to the Tonankai earthquake. A similar downward migration pattern also can be recognized regarding the 1952 Tokachi-oki earthquake. In this case the deepest earthquakes reached about 400 km. This may be one of the intermediate-term precursory phenomena of great thrusttype earthquakes in subduction zones. Recent observations in the Tokai district along the Suruga Trough, where a large earthquake is expected to occur in the future, suggest a similar downward migration pattern in the land area.

Key words

Intermediate-term precursor downward migration seismic gap doughnut pattern subduction zone Tonankai earthquake Tokachi-oki earthquake Tokai earthquake 


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  1. Association for the Development of Earthquakes Prediction (1983),Precursory phenomena of earthquakes, (2) The Tonankai earthquake. Ass. Develop. Earthquake Predict., Tokyo (in Japanese).Google Scholar
  2. Inouye, W. (1965),On the seismicity in the epicentral region and its neighborhood before the Niigata earthquake. Quarterly Journal of Seismology29, 31–36 (in Japanese).Google Scholar
  3. Katsumata, M. andYoshida, A. (1980),Change in seismicity and development of the focal region. Papers in Meteorology and Geophysics31, 15–32.Google Scholar
  4. Mizoue, M., Nakamura, M., Seto, N., Ishiketa, Y. andYokota, T. (1983),Three-layered distribution of microearthquakes in relation to focal mechanism variation in the Kii Peninsula, southwestern Honshu, Japan. Bull. Earthquake Res. Inst., Univ. Tokyo58, 287–310.Google Scholar
  5. Mogi, K. (1969),Some features of recent seismic activity in and near Japan (2), Activity before and after great earthquakes. Bull. Earthquake Res. Inst., Univ. Tokyo47, 395–417.Google Scholar
  6. Mogi, K. (1973),Relationship between shallow and deep seismicity in the western Pacific region. Tectonophysics17, 1–22.Google Scholar
  7. Mogi, K. (1981),Seismicity in western Japan and long-term earthquake forecasting. InEarthquake Prediction, An International Review (ed. D. W. Simpson and P. G. Richards) (Maurice Ewing Ser.4, 43–51, AGU, Washington, D.C., 1981).Google Scholar
  8. Mogi, K. (1984/85),Temporal variation of crustal deformation during the days preceding a thrust-type great earthquake—the 1944 Tonankai earthquake of magnitude 8.1, Japan. PAGEOPH122, 765–780.Google Scholar
  9. Mogi, K. (1985),Earthquake Prediction (Academic Press, New York).Google Scholar
  10. Mogi, K. (1986),Recent earthquake prediction research in Japan. Science233, 324–330.Google Scholar
  11. Mogi, K. (1987a),Recent seismic activity in the Tokai (Japan) region where a large earthquake is expected in the near future. Tectonophysics138, 255–268.Google Scholar
  12. Mogi, K. (1987b),Presursory seismic activity before the 1944 Tonankai (Japan) earthquake—Focusing on the downward migration of seismic activity. Tectonophysics139, 205–221.Google Scholar
  13. Mogi, K. (1987c),The relation between the duration of long-term precursors and the magnitude of the subsequent earthquake. Tectonophysics142, 163–172.Google Scholar
  14. Ohtake, M. (1980),Earthquake prediction based on the seismic gap with special reference to the 1978 Oaxaca, Mexico earthquake. Report of the National Research Center for Disaster Prevention23, 65–110 (in Japanese).Google Scholar
  15. Raleigh, C. B., Benett, G., Craig, H., Hanks, T., Molnar, P., Nur, A., Savage, J., Scholz, C., Turner, R., andWu, F. (1977),Prediction of the Haicheng earthquake. EOS Trans. Amer. Geophys. Un.58, 236–272.Google Scholar
  16. Rikitake, T. (1975),Earthquake precursors, Bull. Seismol. Soc. Am.65, 1133–1162.Google Scholar
  17. Rikitake, T. (1979),Classification of earthquake precursors. Tectonophysics54, 293–309.Google Scholar
  18. Sato, H. (1977),Some precursors prior to recent great earthquakes along the Nankai trough. J. Phys. Earth25, Suppl., S115-S121.Google Scholar
  19. Scholz, C. H., Sykes, L. R. andAggarwal, Y. P. (1973),Earthquake prediction: A physical basis. Science181, 803–809.Google Scholar
  20. Tsubokawa, I. (1969),On relation between duration of crustal movement and magnitude of earthquake expected. J. Geod. Soc. Japan15, 75–88 (in Japanese).Google Scholar
  21. Utsu, T. (1968),Seismic activity in Hokkaido and its vicinity. Geophys. Bull. Hokkaido Univ.20, 51–75 (in Japanese).Google Scholar
  22. Whitcomb, J. H., Garmany, J. D. andAnderson, D. L. (1973),Earthquake prediction: variation of seismic velocities before the San Fernando Earthquake. Science180, 632–635.Google Scholar
  23. Yamazaki, F. andOoida, T. (1985),Configuration of subducted Philippine Sea Plate beneath the Chubu District, central Japan. J. Seismol. Soc. Japan38, 193–201 (in Japanese).Google Scholar

Copyright information

© Birkhäuser Verlag 1988

Authors and Affiliations

  • Kiyoo Mogi
    • 1
  1. 1.Earthquake Research InstituteUniversity of TokyoTokyoJapan

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