Today's advanced Japanese economy has been formed basically by the exploitation of minerals and the development of the heavy-chemical industries which use minerals as rowmaterials and energy, since the Meiji period. However, on the regional level, there are few cases where both mining and manufacturing developed in the same region. Generally, while the mining industry was located in secluded places in the mountains, the heavy-chemical industries were established in coastal areas. In contrast with the remarkable development of the heavy-chemical industries through the free trade since 1963, the mining industry faced the worst crisis in its history. In 1955, the number of mining laborers in Japan totaled about 413, 000, but it drastically decreased to 58, 000 (14 percent of the former figure) in 1980. In the mining cities all over the country, the collapse of a regional society has become a serious problem after the decline of the mining industry. A chief countermeasure through which a collapsed regional society will find a way out is industrialization.
This study is an attempt to consider the change of the mining laborers by using the case of the declining mining industry in the Hitachi mining-manufacturing region. I further would like to clarify some factors which prescribe the re-employment of the laborers.
Hitachi City is located 130 km north of Tokyo. Since Hitachi Mine was initiated as a modern industry in 1905, two enterprises, Nippon Mining Company and Hitachi Company Ltd., developed. The population of Hitachi City is now about 205, 000. As Hitachi Mine declined since 1962, the mining workers decreased from 4 017 down to 500.
The results of this study are as follows:
1. The mining laborers can be divided into the administrative-technical group and the operative group. Although the administrative-technical group was to be the core force to resuscitate Nippon Mining Company and the regional society, they were transferred to subsidiary companies before the retreat of the company. The operative group comprised by mining and industrial workers stayed behind.
2. Within the operative group, the young workers quickly changed their occupations or transferred to subsidiary companies. The middle-aged workers stayed at the company till the mine close down or transferred to subsidiary companies. And the older workers retired before reaching the age limit. In other words, whereas the young work force was fluid, the older one was rigid.
3. The change of the mining laborers was typified by the employment of the manufacturing industry, especially of Hitachi Company Ltd. and its affiliated companies. Children of the mining laborers took employment at Hitachi Company Ltd. and its affiliated companies after the completion of schooling. The young mining workers became employed mainly by the affiliated companies and the middle-aged or older workers obtained employment at the subcontract, small-scale factories. In sum, the younger the mining laborers were, the easier the change into the manufacturing labor force of Hitachi Company Ltd. was. As the ages of laborers became older, they switched more easily to the subcontract, small-scale factories.
4. The types of the manufacturing industry into which the middle-aged or older workers moved are mainly the electrical machinery industry of the subcontract factories of Hitachi Company Ltd. and the material working industry similar to the mining industry. One factor which prescribes these occupational changes is that the manual labor with simple machines in these industries resembles the mining operations so familiar to them.
5. Besides the manufacturing industry, the mining workers took employment in various industries. However, what these industries have in common is the fact that their operation types resemble those of the mining industry.

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Marine terraces formed during the last interglacial maximum of 125 KA and following high stands of sea level at 100 KA, 80 KA and 60 KA, are recognized at many localities throughout the world (Miyoshi, 1983). In Japan one or two marine terraces (Terrace I and Terrace II in descending order for this study) are found at altitudes lower than the last interglacial maximum terrace (S terrace). No radiometric dating for these terraces, excluding Kikai Island (Konishi et al., 1974) and South Kanto (Machida, 1975) has been made.
The purpose of this paper is to estimate the age of Terrace I and Terrace II in Japan, by using regression equation gradients (Ota et al., 1968). The gradients are calculated by plotting heights of the S terrace against younger shorelines, assuming that the rate of uplift has been uniform since 125 KA. Fifteen areas are selected in this study (Fig. 1 and Table 1), where previous work indicates that Terrace I and/or Terrace II are well developed and heights of former shoreline have been measured.
In order to test the method described above, the relationship is examined between the heights of 125 KA terrace and those of younger terraces at New Guinea (Veeh and Chappell, 1974; Bloom et al., 1974), Barbados (Broecker et al., 1968; Mesolella et al., 1969) and New Hebrides (Gaven et al., 1980; Jouannic et al., 1980) where radiometric dating data are available (Figs. 6 and 7). It is clear that the relationship between 125 KA (in abscissa) and 100 KA, 80KA and 60 KA terraces (in ordinate) is a positive, linear correlation. The gradients of the regression equations are 0. 82, 0.63 and 0.44 respectively (Fig. 7), being a function of the age ratio between the older and younger terraces. It can therefore be concluded that the assumption of uniform uplift in these three areas since 125 KA is valid.
Figure 8 shows the relationship of S terrace heights and Terrace I and Terrace II heights by using the above method for five areas in Japan where a large number of height data are available. The gradients of regression equations for Terrace I range from 0.6 to 0.7, and those of Terrace II are 0.47 and 0.50. The gradient of regression equation for Terrace I is 0.69 and that of Terrace II is 0.47 in the fifteen areas in Japan (Fig. 9). These values agree well with the gradients of 80 KA terrace (0.63) and 60 KA terrace (0.44) from New Guinea, Barbados and New Hebrides. It is probable that Terraces I and II were formed at 80 KA and 60 KA respectively, when sea level was relatively high due to the glacial eustasy. Terraces I and II can thus be correlated with the Obaradai and Misaki surfaces (Machida, 1975) in South Kanto. The marine terrace sequence in Japan is thus 125 KA (S), 80 KA (I) and 60 KA (II) terraces in descending order. The marine terraces formed at 100 KA, which is correlated with Hikihashi surface of South Kanto, are not recognized in this study.
Terrace I is well developed, its marine sediments bury bedrocks with irregular relief and its facies suggest transgression. In contrast with this, Terrace II is only locally developed, its marine sediments are thinner and cover an erosional bedrock surface (Fig. 10). It is a commom tendency in many areas of the world that the 80 KA marine terrace is well developed and its sediments suggest transgression (Miyoshi, 1983). Some sea level curves (Fig. 2) show that paleo sea level after the last interglacial maximum was relatively high at 80 KA, in contrast to a lower maximum at 60 KA. This trend is consistent with the marine terrace sequence in Japan.

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River water temperature has been studied from various view points such as biological or ecological. Even in hydrology, river water tern perature has been treated only as a factor of water quality, and there are few investigations about changes in river water temperature with precipitation-runoff process besides snow-melting.
In this paper, changes in river water temperature during a rainfall-runoff event were studied in the small vegetated watershed which is located about 20 km northeast of Mt. Fuji and has a drainage area of 0.12km². Under a heavy rainfall of typhoon on Aug. 19-22, 1981, river water temperature was measured together with air temperature, soil tempera-ture, groundwater temperature, groundwater level, discharge, rainfall and surface runoff. As a result, it was observed that river water temperature rose suddenly about 0.2_??_0.5°C when surface runoff occurred and hydrograph reached its peak. On the other hand, the peak of groundwater level lagged behind rises of river water temperature. Groundwater tempera-ture and soil temperature kept constant. There were no remarkable changes in air tempera-ture during that time. Therefore, the cause of this phenomenon was attributed to a direct runoff accompanying thermal transfer.
Two simulation models of changes in river water temperature with rainfall were present-ed. One model takes heat balance and mixing of water body into consideration, and the other model is based on a tank model. The former model represented that if direct runoff component occupies about 10% of total runoff, river water temperature rises about 0.2_??_0.5°C. Hydrograph separation by using specific conductance showed that direct runoff was nearly equal to 10% of total runoff at the peak of hydrograph. The latter model also proved that rises of river water temperature occur due to direct runoff.

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