There are few differences in the characteristics of topography and precipitation between the Arakawa and the Tainai River basins in Hokuriku District. The area of the Arakawa River Basin is 8 times as large as that of the Tainai River Basin. A more extensive fan should be formed for the Arakawa River. But the Tainai River has a typical fan, while the Arakawa River has a small and irregular one in the lower part.
To clarify the cause of the difference mentioned above, the authors examined 1) the geometry of the topography of the drainage basin, 2) the effects of the gorges and intermontane depressions on production and transportation of sediments, and 3) the geomorphology of the alluvial plain.
1) We first made a grid square map on the whole drainage basin in order to process the geomorphological data by computer. We found that the area of the small relief energy is distributed not only at the Oguni Intermontane Depression but also at the upper reaches of the depression. High relief energy is distributed only near the summit of the mountain range. This shows that the cycle of erosion of the upper part of the Arakawa River Basin has reached early old stage. And the Arakawa Canyon shows the mature stage. In the case of the Tainai River, almost all of the mountainous region shows high relief energy and the cycle of the erosion of the area belongs to mature stage.
We drew a restorted topographical map of the basins by using grid square data and computer programs, and measured the volume of erosion in each cell. It was founded that the total volume of the erosion of the Arakawa River Basin is about 5.9 times that of the Tainai River and the average depth of erosion of the Tainai River Basin is about 1.3 times that of the Arakawa River. Based on the above-mentioned results, the explanation of the difference in fan development between the two rivers is insufficient.
Then we examined the longitudinal profiles of the rivers, river bed sediments, and features of the flooding in August 28, 1967. There is a knick point in the Arakawa Canyon. The knick point is situated at the junction of the two graded courses. This shows that a considerable portion of the sediments transported from the upper reaches is deposited in the upper reach of the knick point, and only finer sediments flow down through the knick point. We clarified this phenomenon by analyzing the river bed sediments.
By examining the map showing the state of flooding, we can understand that the sediments originating in branches which run into the Oguni Intermontane Depression were mainly deposited at the low plain, and sediment transport along the Arakawa River (a trunk river) was minor. On the other hand, sediments can be transported to the downstream reach of the Tainai River, partly because the gradient is steep, and partly because the Kurokawa Intermontane Depression is small and any conspicuous knick points are not formed along the Tainai River course.

View full abstract

From long-term variations of weather hazards of Japan, Maejima and Tagami (1986) found the “Cold Age” from 15th to 19th century. During this period Japan had frequently suffered from severe famine due to cool summer weather. This paper attempts to reconstruct the summer weathers in the 1750's, including the notorious famine of 1755, the Horeki famine.
From the weather records as proxy data in 11 historical diaries the weather calendar diagrams for 1751-1760 were prepared. By means of synoptic view of weather distribution in those diagrams, the characteristics of the seasonal march of pressure pattern were estimated for each summer. Then, using the weather pattern, a method was introduced to estimate the temperature and the frequency of pressure pattern.
The formula to estimate the monthly mean temperature, by using present instrumental data, is follows:
y=c₁x₁+c₂x₂+…+c₁₅x₁₅+c₁₆x₁₆
where independent variables x₁, x₂, …x₁₅, x₁₆ denote sixteen types of weather pattern, and dependent variable y denote monthly mean temperature in a given location. Using the data for latest 30 years, coefficients c₁, c₂, …c₁₅, c₁₆ were calculated to estimate y with minimum error sum. Thus, we calculate the monthly mean temperature in the historical past by using the frequency of historical weather pattern.
Then, from the relationship between pressure pattern and weather pattern in the instrumental period, historical pressure pattern was inferred.
The results obtained are summarized as follows:
(1) In 1750's the summer weather was different from year to year. In July 1755, a notorious famine year, northern Japan suffered from cool air flow from the northeast, and it was rainy, because of the stagnation of stationary front, in central and southern Japan. On the contrary, in August 1755 it was rainy only in the northern part of northern Japan, while it was hot and dry in central and southern Japan.
(2) The temperature for July 1755 was 3°C lower than the present normal (1951-80) at Morioka and Ishinomaki in the eastern part of northern Japan. Standard deviation of error sum of estimation was 0.7°C (Morioka) and 0.6°C (Ishinomaki). In August 1755 the temperature at Morioka and Ishinomaki was not low.
(3) In July 1755 the frequency of summer monsoon pressure pattern was low, while the frequency of stationary type of front running along the Pacific coast was high. In August 1755, the frequency of summer monsoon pressure pattern was low, while the frequency of stationary type of front running over nothern Japan was high.

View full abstract

[in Japanese]

View full abstract

In recent years, there are several studies of the vertical differentiation of urban functions in Japanese cities. A few problems, however, still remain to be done in the methods in these studies. The auther attempted to refine these methodologies and to apply the refined method for the data obtained in Nagasaki City.
The study area is delimited reffering to the distribution of the land value. The derived area includes not only the CBD but also the whole built-up area of Nagasaki City. We investigated the buildings, which have six or more stories and have multi-functions. The total number of such buildings in the study area was 185.
In this study, we applied two types of minimun units to analyse the spatial patterns of the distribution of buildings. One of them is the grid system, in which each cell has about 300 meters by 500 meters area. The other one is the zoning system derived comparing the maximum land value. In this zoning system, whole area is divided to six zones, in terms of the levels of land value.
The results of the study are as follows:
1) The vertical differntiation of urban functions is patterned in a hemispheric form, as K. Suzuki (1979) has pointed out. This trend is more clearly shown in the results using six zoning systems comparing the results using grid system. Therefore, the vertical differentiation is most tacifly by the land value.
2) The distribution of urban function is similar to the one reported by Suzuki in higher land value area. That is, many urban core functions such as R1 (retail), R2 (amusement), S1 (personal services), S2 (servises for enterprises), O (office) and F (finance) exist at the lower floors; both urban core functions and outer area functions such as P (parking), I (residence) and X (others) exist at the upper floors. In lower land value areas, both urban core functions and outer area functions occupy the lower floors, only I (residence) occupies the upper floors. But in the lower floors of highest land value area, functional distribution is different from Suzuki's conclusion that is, there is only R1 (retail) function.

View full abstract

This paper describes forms and formative periods of beach ridge ranges on three Holocene coastal plains in the southeastern part of northeastern Japan.
In the first place, numbers and morphological features of beach-ridge ranges have been examined through aerial photographic interpretation, fieldwork and topographic profiles produced from 1:2, 500 national large scale maps. Secondly, based on ¹⁴C ages of backmarsh deposits behind each beach-ridge range and nearshore deposits including shell fossils, formative period of each beach-ridge range was estimated. These facts mentioned above were used in correlation of beach-ridge ranges on the coastal plains.
Results are summarized as follows.
1) Beach-ridge ranges on these coastal plains are divided into three on the basis of morphological evidence and formative periods, although some differences are recognizable among the three coastal plains. From comparison of geomorphological and geologic settings, it is inferred that these differences result from effect of wave action and morphological variation in basement overlain by alluvium.
2) Each beach-ridge range, in order from inland most, started forming before 4, 000y. B. P., at 3, 000y. B. P. and 1, 700-1, 600y. B. P., respectively.

View full abstract