No suitable method has yet been found for the study on the texture, the structure and the mineral composition of the deep weathered granites, which has been called the Masa. In this paper, it is reported that the writer has made the systematic study of the disintegrated and the weathered granites. Its method is the analysis of the relationship between the distance from the fault and the diameter of the particles, and also the analysis of the cumulative curve for the size distribution, the apparent specific gravity, the seismic sounding, the electric prospecting, the relief quantity. The area reseached by the writer covered nearly over the whole area of Rokko mountains, Hyogo Pref., Dogo Dist., Ehime Pref., Yashima, Kagawa Pref., Sanage Dist., Aichi Pref. and the other regions.

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A Study of ground water quality in Riyadh (capital of the Kingdom of Saudi Arabia) waters is presented. The chemical study indicates the presence of about 24 elements in these waters. Most of the metals and toxic elements have been found below the upper permissible limits suggested by various health organizations. The hydrogeological study indicates the source of these waters is two aquifers. The waters from these aquifers are found to be Ca-CI and Mg-SO4 type, and are believed to be of marine and meteoric origin. The waters from the Riyadh region are found to be suitable for drinking purposes.

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A transient dispersion-convection equation, which appears in the problems of heat and mass transport in flowing groundwater, is solved numerically by means of a finite element method coupled with the method of characteristics. Numerical errors such as numerical dispersion and oscillation, generally encountered in solving dispersion-convection equations numerically, can be eliminated by using the proposed method. Numerical solutions by the characteristic finite element method showed good agreement with analytical ones.

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[in Japanese]

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In the underground of Nobi plain, sedimentary layers exist more than 1,500 m tiick. In the lowest part of these layers, there is the ultra-deep underground water the temperature of which is about 50° C.
For the purpose of knowipg annual variation on the chemical compositions of these waters, nine wells were selected to investigate water chemically once a year from 1973 to 1977.
The chemical compositions of these waters are as follows, NaHCO₃ type of water was found in four wells, NaCI type in other four wells and NaC1-NaHOO₃ type in one well.
The annual variations observed on the chemical compositor's of these well waters were only less than 10% during five years for the former two types, while one well of the last type indicates rather large annual fluctuation. As for the last type well, Cl^- contents of water changed widely, ranging from 101 to 488 mg/l, and it corresponds to the change of the water type from NaHCO₃one to Nag one.
It is assumed that the underground water of NaHCO₃ type (122 mg l-I) occurs in the aquifer of upper hodzon in sediments, while that of NaCI type (341 mg C1^-/I) exists in the lower one.
The well in which large annual variation was observed, had the strainers at about 250 m length, and the water was seemed to be derived both upper and lower aquifers. It seems that the large annual variation is due to the variable contribution to the well water from two different aquifers.

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Preseismic and coseismic changes in groundwater level at the earthquake on February 20 and June 12,1978, both of which occurred off the coast of Miyagi prefecture, are studied. The study was conducted by the data recorded at wells installed for the protection of groundwater resources in Miyagi prefecture. The record of groundwater level change is so complicated due to superimposing of various kinds of noises, that processed trend lines instead are mainly analyzed. The trend of groundwater level for 30 days,10 days and 0.5-1 days preceding each earthquake showed normal pattern, without any signs of preseismic effects. The coseismic change in groundwater level is detected at all wells. The direction of the change did not coincide with stress distribution which is estimated from initial shock of seismic wave. The amplitude of level changes decreased with an increase of depth of strainers. This phenomenon is regarded as a result of sediment compaction by seismic vibration.

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[in Japanese]

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Using six years of data, the relationship between the depth of the river water and the water table depth of the shallow groundwater in paddy fields was studied and the following obtained;
1) The relationship between D (the depth of the water table of the shallow groundwater in paddy fields measured from the ground surface) and H (the water depth of the Aya River) could be expressed by a simple, linear equation as shown in Eq. (3).
2) The values of RDH show that the degree of the relationship between D and H varied with the values of Hg (the height of the well sites above sea level). A linear equation was constructed, as shown in Eq. (4), showing the relationship between RDH and Hg.
3) The degree of the relationship beween D and H also varied with L (the distance of the well from the Aya River). Eqs. (5) and (6) were constructed to show the relationship between RNDH and L. RNDH had the same value as RDH during the non-irrigation period.

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The customary method to analyse the proper discharge of well fails to value the well and aquifer loss. And, the customary method to analyse the well and aquifer loss fails to determine the proper discharge of the well. To overcome the difficulties mentioned a practical method for their simultaneous determination and a new conception for the technical term“ Proper Discharge” is proposed.

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Using the data showing the values of the correlation coefficient (R) of the monthly average water table depth (D) between the base well (DR-1) and each well, we made a study to see the characteristics having R and their frequency.
We found that the relationship between the frequency (f) in percent of R and R seemed to be expressed by an equation, Eq. (1), that was constructed by applying the Poisson distribution function.

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In order to show geophysically the fluctuation of the water table of shallow groundwater in paddy fields for most of a given area from a particular well (base well), the correlation coefficient (R) between the water table depth at the base well and the ones at any other well in the area was employed as shomn in Eq. (1).
ECC-curves were drawn and from these curves, the ECC-maps were constructed as shown in Figs.2 to 5.
From these maps, it was found that the fluctuation of the monthly average water table depth for most of the study area was strongly correlated with the ones at the base well.

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A study was made to estimate the values of aquifer increasing or decreasing two consecutive months and to find their characteristics by means of a time series analysis. The results that were obtained are as follows:
1) The values of aquifer increasing or decreasing during consecutive months, dV, were obtained by Eq. (1), and the results showed that the values of dVvaried from 158.95× 10⁴m³ to 186.49× 10⁴m³as listed in Table 1.
2) To see the variation of dVduring the period (March to February), the term of γ was defined by Eq. (2), and the results are shown in Figs. lA to 1D. To show mathematically variation of γ (the curves show the variation of γ ), Eqs. (3) and (4) were constructed by applying the FOURIER series. The theoretical values of γ, γ, were obtained by these equations as shown in Figs.1A ot 1D. As shown in these figures, the theoretical values coincided with the observed ones.
3) The values of the cumulative γ in the positive values, γ _t+, were obtained by Eq. (6) that was constructed by applying the GOMPERTZ curve. Also the cumulative values ofγ in the negative, values, R_t-, were obtained by using Eq. (7) that was constructed by applying the LOGISTIC curve. The theoretical values obtained by these equations (the open circles) coincided with the observed ones (the solid circles and the crosses) as shown in Figs.2A to 2D. References

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Using the FOURIER series, we obtained the theoretical equations, (3), (4) and (5) that showed the manthly average cyclic variation of the shallow groundwater temperature near the water table for a year. The values calculated by Eqs. (3), (4) and (5) were close to the observed ones as shown in Figs.2,3 and 4.

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Applying the theory of log-normal-probability distribution, we obtained the theoretical equation showing the relationship between alA and D as listed in Eq. (3), and we referred to this equation as the depth-area-curve equation. We also used Eq. (6), Eq. (7) and Eq. (8) to calculate the values of Dmode, Dmedian and Dmean, respectively. The values calculated by the theoretical equation were compared with the values observed. The results were as follows;
1) The deviation of the theoretical values of Dmode from the observed ones (that were calculated by Eq. (9)) was 41.5% at the maximum value and 1.6% at the minimum one.
2) The theoretical values of a/A at Dmode agreed closely in practice with the values observed.
3) For the values of Dmedian, the theoretical values agreed well with the values observed.
From these results, we concluded that we would be able to use the theoretical equations obtained here to estimate the depth-area curve or the relationship between the water-table depth and its corresponding area, Dmode. Dmedian and Dmean for a given region for a given period. References

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In the last paper“ Concerning the Coefficient of Storage” publised in this idutnitl Vol.14 (1968), the writer advocated a thinking Way of the decreasing of ground-water orage by pumpage aid, as the result, diminishing of coefficient of storage, which teas a kind of measure to evaluate the ground-water storage. But he described also in the paper that his advocation was no more than an idea and did not reach its conclusion.
Through the study thereafter, the writer noticed an inperiection in the thinking way or the treatment of the unit of pumpage periodt. Then he corrected them and discovered an easy graphycal solution, under the condition remaining transmissibility concerned unchangeable.

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