Time Changes of Transfer Functions at Kakioka Related to Earthquake Occurrences ( II )
Sano, Y.
Abstract
In this paper, earthquake precursor changes of transfer functions at Kakioka are statistical1y re-examined in detail on the basis of a more reasonable selection of earthquakes than in the previous paper.
From the present re-examinations, the earthquake precursor changes in transfer functions are more clearly confirmed than in the previous study, especially in short-period components such as 10, 20, 30, 60 minutes. Furthermore, the present results are also confirmed in general features from the same analyses for other transfer function data by the method of power spectral analysis which is different from the present one of the Fourier transform analysis and the least square method.
As another new feature in time change of transfer functions, certain kinds of periodic changes with a periodicity of about 27-79 days are suggested in longer-period components than 60 minutes.
