The spectral analysis of waveforms from moderate and weak earthquakes in the Kurile-Kamchatka region allows one to rather reliably discriminate between foreshocks of forthcoming strong events and independent swarms of seismic shocks. Anomalously high frequencies of seismic radiation from foreshock sources are due to an anomalous rigidity of the seismogenic medium. Based on significant frequency anomalies determined from seismic records of foreshock sequences, the methods developed by the authors can be applied to recognize medium- and short-term seismological precursory effects.
major earthquakes, foreshocks, Kurile-Kamchatka Arc, analysis of waveforms.
1. Aptekman, Vulkanol. Seismol., no. 2, 1989.
2. Balakina, Fiz. Zemli, no. 12, 1995.
3. Boldyrev, Structure of Seismic Focal Zones, 1987.
4. Goryachev, Main Characteristics of the Tectonic Development of the Kurile-Kamchatka Zone, 1966.
5. Ishida, Bull. Seismol. Soc. Am., v. 70, 1980.
6. Kronotski Earthquake..., Kronotski Earthquake of December 5, 1997 in Kamchatka: Precursors, Peculiarities and Consequences, 1998.
7. Mogi, Prediction of Earthquakes, 1988.
8. Rodnikov, Eastern Pacific Island Arcs, 1979.
9. Rogozhin, Tectonics and Geodynamics: General and Regional Aspects Conf. Proc., vol. 2, 1998.
10. Rogozhin, Fiz. Zemli, no. 5, 2000.
11. Shikotan..., Shikotan Earthquake of October 45, 1994, Inf. Analit. Byull. FSSNPG, extra issue, 1994.
12. Shikotan..., Shikotan Earthquake of 1994, Inf. Analit. Byull. FSSNPG, special issue, edited by S. S. Aref'ev and N. V. Shebalin, 1995.
13. Tarakanov, The Velocity Structure of the Upper Mantle in the Asia-to-Pacific Transition Zone, 1997.
14. The Crust..., The Crust of Island Arcs and Far East Seas, 1972.
15. The Structure..., The Structure of Seismic Focal Zones, 1987.
16. The Structure..., The Structure of the Sea of Okhotsk Floor, 1981.
17. Udintsev, Geomorphology and Tectonics of the Pacific Ocean Floor, 1972.
18. Utsu, J. Phys. Earth, v. 28, 1980.
19. Zakharova, J. Earthquake Prediction Res., v. 6, no. 3, 1997.
20. Zakharova, J. Earthquake Prediction Res., v. 7, no. 2, 1998.
21. Zlobin, Seismological Constraints on the Structure of the Crust and Upper Mantle of the Kurile Island Arc, 1987.
