Prehistoric fault activities along the Atera fault, one of the most prominent active strike slip faults in central Japan, have been revealed from studies on faulted humic soil layers and river terraces. Many organic samples for radiocarbon datings were collected from the outcrop on the Atera fault at Rgo, Kashimo Village, Gifu Prefecture, in order to determine the periods of prehistoric earthquakes. Displacements of river terraces around Sakashita Town on the right bank of the Kiso river, have been measured in order to deduce the amounts of coseisimic displacements.
Prehistoric earthquakes deduced from fault activities have been repeatedly taken place along the fault at the periods of before 10, 300 y. B. P., 7, 900 y. B. P., 5, 500 y. B. P, and 1, 850 y. B. P., Recurrence intervals between succeeding two earthquakes are not equal but differ from each other judging from the amounts of displacements associated with each earthquake. The average vertical slip rate has been calculated as 0.71 m/10³ yrs. from the amounts of coseismic displacements obtained from faulted river terraces and the receurrence intervals of earthquakes. The average lateral slip rate is calculated as 3.55 m/10³ yrs., since it is known that the left lateral displacement is about 5 times larger than the vertical one (Sugimura and Matsuda, 1965). Along the Atera fault a great earthquake is presumed to occur within a thousand years in future, based on “Time-predictable recurrence model for large earthquakes” (Shimazaki and Nakata 1980).

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Land readjustment projects have had a great influence on providing urban areas with subdivisions in Japan as they are said to be a mother of town planning. In a suburban area, these projects have been used as a method of preventing urban sprawl. Put the projects are not always supported by those who live where the projects are planned. The major reasons of this are these two: one is that the people have to bear the expenses for operating the project and offer some of their land for public facilities such as parks, schools and roads, and the other is that houses are built close to the farmland, making the farming conditions worse rapidly.
In this paper, the writer summarizes land readjustment projects in the Tokyo Metropolitan Area, and focuses on changes of land tenure, destruction of agriclture, and environmental problems consequent to the projects, through the case study of the Hone Land Adjustment Project which was planned for the south end district, facing Tokyo Bay, in Edogawa-ku, Tokyo. And through the study, the following tendencies can be recognized.
1. Projects promoted by an individual or an association account for the largest percentage in case and area of all the land adjustment projects in Tokyo which are based on the Land Readjustment Project Act. Cases of the Projects are often found in the Tama district (especially in the Tama Hilly district) after 1970, thought they were found in the special ward area (especially in Adachi-ku, Katsushika-ku, Itabashi-ku, and Edogawa-ku) before then (Fig. 1). The area of roads accounts for the largest area in all the public facilities constructed by these land readjustment.
2. Hone, once a marsh, was reclaimed in the middle of Edo Period by the inhabitants of Urayasu adjacent to Hone, Chiba Prefecture. The inhabitants of Hone cultivated layer and grew vegetables, and they sold these products to wholesellers in Tokyo. But in 1960's, land subsidence had been occurring continually, and the cumulative subsidence (from 1960 to 1973) amounted 1.703 m, so the farmland became a marsh again (Fig. 3). Moreover in 1963, the reclamation of Tokyo Bay deprived the Hone inhabitants of the right of layer cultivation. These two facts made it difficult for the inhabitants to earn their living only by agriculture and fishing.
3. The enterprises and real estate agents bought these marshes as a speculation (Fig. 4).
4. As urbanization was going on with the construction of the Tozai Subway Line, the Hone Land Readjustment Project was planned in 1968. Most of the leaders of the project were chosen from people who had some land in Hone, but who lived outside Hone. They owned the land as a speculation.
5, In the process that farmers in Hone were leaving agriculture the project was planned, and all the farmers were determined to leave agriculture through the project.
6. The area of roads which were included in the Tokyo Metroporitan Town Planning is larger in all the area of the roads built by the project. After the completion of the project, small houses are being built densely in Hone (Fig. 5).
7. Some industries and individuals who bought these marshes filled up the marshes with various industrial wastes. Especially sexivalent chrome among them caused soil pollution and it affected the operation of the project (Figs. 3 and 5). Soil pollution caused the price of the land temporarily to fall. Unless the method of handling the soil with such industrial wastes is made clear, it would be difficult to solve the problem of soil pollution in Hone.
The high price of land potentialized by the project can be realized when it is sold, so the people who owned the land as a speculation got the most benefit of the project. The Hone Land Readjustment Project changed the suburban agricultural area to a residential section. This residential community is far from a well-established one.

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The objective of the present paper is to make clear soil water characteristics of Kanto Loam by presenting data obtained in laboratory. The experimental apparatus originally developed by Richards was used to measure the pressure head and the hydraulic conductivity for two undisturbed test samples collected from Tachikawa and Musashino loam formations at Yatabe near Tsukuba Academic New Town. The results obtained are summarized as follows:
1. The hysteresis effect between the pressure head and the water content is clearly shown for Kanto Loam.
2. Maximum water content for the sorption curve is smaller than that of the desorption curve because a part of pore space is filled with entrapped air. The values of critical saturation for two test samples are 0.93 and 0.95.
3. The water-entry value is nearly equal to a half of the air-entry value.
4. The unsaturated hydraulic conductivity depends on the pressure head and the water content.

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Uphill-facing scarplets are often distributed on the high mountain slopes of Japan. They have been called “double ridges”, or “linear depression”, the origin of which has been disputed among geomorphologists. In this paper the author investigated their topographical characteristics such as mode of occuerrence, height, distribution and cross sections of rides on which they appear. He also refers to their origin applying a two-dimensional finite-element calculation of the self gravitational stress to a model mountain, on the slopes of which the scarplets are often distributed.
The results can be summarized as follows.
1. The scarplets are mostly recognized in high mountain areas with high relief caused by the rapid uplift during the Quarternary (Fig. 2).
2. Most of them appear on the mountain slopes higher than 2, 000m a. s. l., but some are recognized on the slopes lower than 1, 000m a. s. l. in case of the slopes with high relief (figs. 3, 5 and 6).
3. They are mainly formed on ridges deeply dissected by V-shaped valleys (e. g. the Kurobe) (Fig. 7), cross sections of which consist of two parts; very steep lower slopes formd by deepening and gentle upper slopes or flat surfaces around ridges. Therefore, the sections generally show convex outlines as a whole (Figs. 8 and 9). Scarplets are usually located just above breaks between steep and gentle slopes.
4. Brittle fractures caused by the self load of mountain will be expected to occur around ridges of mountain (Figs. 11 and 12) by the analysis applying the finite-element method. Therefore, uphill-facing scarplets may be originated from the subsidence of ridges caused by local faulting.

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