Time Change of Transfer Functions at Kakioka Related to Earthquake Occurrences （ III ) -Periodic Changes of Transfer Functions and Other Related Phenomena-
Sano, Y.
Abstract
Some periodic changes of transfer functions at Kakioka have been examined by the Fourier analysis and the superposed epoch method with relation to those of neighbouring earthquake occurrences and the geomagnetic activity. The data analyzed are the same as used in the previous papers.
The most outstanding results in the present study is that both transfer functions for longer periods than 60 min and earthquake occurrences near Kakioka during the epoch from Mar. 1977 to Dec. 1978 show significant 27-day periodic changes, while the geomagnetic activity does a predominant 29-day one. Most of remarkable periodic changes of transfer functions seem to be closely related to those of earthquake occurrences, but a little to those of the geomagnetic activity.
However, the mean 27-day periodic change of transfer functions for the long periods is exceptionally larger than the other for the short periods and that expected from the effect of the corresponding change of earthquake occurrences. It will be strongly suggested that such a 27-day periodic change of transfer functions is possibly intensified by some origins other than the earthquake precursor effect and the geomagnetic activity dependence.
