All mountainslides occured in the area of Okuzure seashore in the past 6.5 years are listed on tab. 1. Each of coefficient K for dry and R for precipitate is defined in formulas (1) and (3). The changes of K and R, which are probably closely related to cause mountainslides, are shown figs. 4-12. In comparison with the list of mountainslides in tab. 1 and the changes of K and R, the mountainslidesof this area are classified into four types: a dry type and three wet types; three of wet types are furtherdevided into W-A, W-B and W-C as shown in tab. 3. It is a characteristic of the dry type that a mountainslide does not occur in the culmination of R, but occursin the following decreasing state. In the wet type a mountainslide occurs in the increasing state R; in thiscase a clear ominous peak is seen before the culmination. The dry type, W-A and W-B types have very high possibilities to cause mountainslides, but in W-C typethe possibility is low.