Russian Journal of Earth Sciences
Vol. 3, No. 3, August 2001
Spectral characteristics of foreshocks preceding major earthquakes
of the Kurile-Kamchatka Arc and their application to the prediction of the main shock
time
L. S. Chepkunas, E. A. Rogozhin, and V. I. Benikova
Abstract
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.