The chromium contents of 50 rock samples, belonging to the Cenozoic volcanic rocks in the western part of the San-in distrct in west Japan, were determined by atomic absorption method. The volcanic province of this district is divided into Abu, Mishima and Otsu areas by the distribution of volcanic rocks.
In Abu area the chromium contents of the alkaline rocks are 75-390 ppm and of the calc-alkaline rocks are 8-510 ppm, in Mishima area the alkaline rocks are 239-436 ppm, in Otsu area the tholeiitic rocks are 11-423 ppm and of the alkaline rocks are 120-508 ppm (high iron alkaline rocks are 120-185 ppm), resectively. From these data, the chromium contents of the volcanic rocks of the western part of the San-in district show the wide range of 8-510 ppm and the average value of 204 ppm.
The chromium contents of the most of the rock samples have the tendency of the decreasing in the progress of crystallization differentiation. Although, as an exception in the case of co-existence of olivine and pyroxene, it is likely that chromium may concentrate in pyroxene rather than in early crystallized olivine.
It is supposed that the alkaline rocks and calc-alkaline rocks are classified on the basis of the chromium contents of the olivine-bearing calc-alkaline rocks as an indicator.

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Thirty-six Quaternary volcanic rocks from the central and eastern Hokkaido, whose major elements were known, were newly analyzed on the minor elements, Cu, Sr, Ba, Ga, Y, Pb, V, Cr, Co and Ni. The relation between the minor and major element abundances of the above rocks were discussed. The general and characteristic features of the volcanoes and volcanic chains are summarized as follows;
1. The kutcharo, Atosanupuri and other post-caldera volcanoes of Kutcharo and Mashu have the same character as those of the Usu and Esan volcanoes of the south-western Hokkaido.
2. Also the Akan volcano has the same character as those of the above volcanoes, except Cu, Cr and Ni elements. This volcano is far richer in these elements than those of the others.
3. The Daisetsu and tokachi volcanoes have nearly the same character as that of the Niseko Volcano of the southwestern Hokkaido. The Daisetsu Volcano is characterized by the high V×1000/FeO+Fe₂O₃ ratio, which is one of the highest value in Hokkaido, and by the rich Cr and Ni contents. The Tokachi Volcano is far poorer in Cr and Ni than The Daisetsu Volcano.
4. The difference of minor element contents between the shiretoko-Akan and the Daisetsu-Tokachi volcanic chains is best represented in Ba and Pb contents. The latter is richer in Ba and Pb than those of the former.
In the Shiretoko-Akan volcanic chain, the rocks of the pigeonitic rock series are richer in V than those of the hypersthenic rock series, as seen in the volcanoes of that in the south-western Hokkaido. The rocks of the Daisetsu-Tokachi volcanic chain, which belong mostly to the hypersthenic rock series, are rich in V and plotted in the pigeonitic rock series field of the rocks from the former chain. In this point, the rocks of the hypersthenic rock series of the latter chain are different from those of the former.
The minor elements of the Tokachi welded tuff are often far from the general character of the Tokachi volcano, which suggests its different genesis.

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The Higashi-nomyo landslide, located in the Niigata prefecture, has occurred repeatedly and caused many severe disasters since the 18 century. The basement rocks of this slide are mainly composed of Tertiary mudstone covered by Quaternary pyroclastics. The surface topography of the area of about 2km², is divided into the upper part of large blocks configration disturbed by primary landslide and the lower part of gentle slope due to many secondary landslides. A greater amount of ground water in the pyroclastic masses of the primary landslide has been the source of water supply for the secondary landslides in the lower part.
The historical and present slides have been the secondary landslides from the large-scale ancient primary landslide mass. The primary landslide occurred before 50ka in the Late Pleistocene and the modern type secondary landslides continued to the present have begun from 6-3ka. A present activity is extending to a part of the of the ancient primary landslide mass.

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