Abstract
Fundamental characteristics of seiches observed around Japan became clear in the previous paper. Seasonal variations of frequencies of seiches at most stations in the whole country are very similar except some stations situated in Hokkaido, Okinawa and inland sea areas. On the other hand, secular variations vary according to stations. Characteristics of two neighboring stations do not necessarily resemble. On the contrary, those of two remote stations are sometimes similar.
In this paper, all stations are classified into three groups using the probability density function of frequencies of seiches and the similarity coefficient of seasonal variations. The similarity of the seasonal variations has close relation to the shape (the maximum value) of the probability density function.
As for stations whose annual changes are much larger than neighboring ones, the tendencies of secular variations do not show good agreements with those of other stations.
It is suggested that the mean magnitude of seiches for many years is not necessarily a stable index for some stations.
