[in Japanese]

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Brown soil was collected from the landslide area, Mie-mura, Nishikano-gun, Nagasaki Prefecture and was studied by X-ray, thermal, infrared absorption and electron microscope method.
It was determined to consist of, beside quartz, feldspar and gibbsite, such clay minerals as illite, Alvermiculite, random mixed-layer illite Al-vermiculite and kaoline.
It may be considered that these clay minerals were largely produced by the weathering of thin layer of biotite developed along the schistosity of spotted graphite sericite schist and promoted the landslide phenomenon along the schistosity of the above-rock.

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On the basis of “Distribution of Landslides in Japan” by Public Works Research Institute, Ministry of Construction, distribution of the number of landslides which exist in areas of 50km×50km is drawn up (Fig. 3).
As a result of comparision of this distribution with “Distribution of Normal Annual Amount of Precipitation” by Meteorological Agency, the following has clarified.
It is ascertained that the region of a great number of landslide has a great amount of precipitation and the region of a small amount of precipitation has a small number of landslide. But, it doern't always follow that the region of a small number of landslide has a small amount of precipitation and the region of great amount of precipitation has a great number of landslide.

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[in Japanese]

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Post la unua raporto pri la tersovigo en la regiono Morito, ni daurigis geologajn esplorojn en pluraj regionoj de tersovigo. Eltrovante klaregajn interrilatojn de tersovigo kaj geologia strukturo, speciale en la regiono Kugi, Higasiija-jamamura, Tokusima gubernujo, ni volas kondensi pri gi kiel sekvantaj linioj.
La tersovigo estas treege influata de fendigo lau aksa eveno, linia strukturo kaj dislokigo en la regiono Kugi.

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Observations have been made of microtremors in an area around the landslide which occurred on the northern slope of Mt. Iizuna in Kinasa-mura, Nagano-ken, April 1973. The spectral curves have a clear appearance with one dominant peak at a period of 0.2 to 0.3 sec. at the locations, where the landslide produces very little effect. While the amplitude spectra near the landslide region spread over a period range of 0.3 to 1.0 sec., and for this reason, it becomes difficult to evaluate accurrately the predominant period. The effect of viscosity may be considered in the superficial layer to account for such spectra. By comparison with the calculations of the amplitude due to multiple reflections of SH waves in two layered half space, the viscosity coefficient is deduced to be about 5×10⁶ to 10⁷ CGS near the landslide region This value corresponds to the Q value of about 1 to 2.
After about one and a half year from the occurrence of landslide, observations were carried out again near the landslide region. From these observations it was concluded that the amplitude spectra vary so that the predominant period appears clearly in the period range of 0.3 to 0.4 sec. Because of a decrease of water content in the superficial layer, the elastic properties may be considered to acquire a stable state perior to the occurrence of landslide.

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