The younger volcanic soils covering Shirasu layer (pumice or pyroclastic flow deposits) in southern Kyushu have a depth of about 5 meters. These volcanic ash soils are able to be divided into at least 10 or 11 types according to their diagnostic features, such as color, degree of pumice weathering, etc., and these soils can be classified into five layers in accordance to their own physical properties. This classification is also equal to the stratigraphic sequence which is decided due to their eruptive sources and succession of volcanic activities; and these layers are, in order of soil horizon, alluvial volcanic ash (black), younger loam (upper, middle and lower loam) and decomposed or secondary Shirasu. Each loam layer is composed of two deposits which are accumulated organic matter and weathered pumice; and these buried soils have shown similar properties variations in each layer, regardless of the location investigated.

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The Tsukabaru hill in the Shirasu soil zone is formed roughly by three soil facies above an impermeable bedrock; that is a volcanic loam soil on the surface, sand in the middle and Shirasu soil at the bottom. In detail, the loam soil on the surface can be classified into four layers, of which the top layer is formed by Kuroboku soil. The Shirasu soil contains small strips, small curved fragments and small bubbles of volcanic glass, and is classified as sandy clay loam. In addition it has less particle density, larger bulk density and less porosity than sand or Kuroboku soil. The unsaturated hydraulic conductivity of Shirasu soil is larger than that of sand in the whole suction range. However, it is less at high suction and more at low suction than Kuroboku soil. The water content of Shirasu soil in the whole suction range is larger than that of sand and less than that of Kuroboku soil, in regards to its moisture characteristic curve. Water in the hill, expect for water at a depth of 2 meters from the surface, is supposed to flow down, changing water. content of sand in middle toward ground water table build up in Shirasu soil layer, in which the water flows in the lateral direction, and springs out on the side of hill where it crosses an impermeable bedrock.

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Energy state and transport of soil water were investigated in conformity with circumferential weather conditions in unsaturated zone of the Tsukabaru Shirasu platform isolated both geographically and hydrologically from surroundings.
This report is intended for making clear the role of unsaturated zone in the hydrological sense.
Taking the soil water suction at 30cm depth (h₃₀) as an index of desorption at the whole surface layer, below 16mm rain water could not and over 64mm could penetrate over 200cm depth at any h₃₀ value before precipitation. 16 to 64mm could penetrate over 200cm depth when the layer was not so dry as h₃₀ exceeded over 200cm H₂O (Table 3).
As profiles which have particular h₃₀ values in different desorption processes show fair agreement with each other except for low h₃₀ values (Fig. 4), it is no problem to adopt h₃₀ value as a desorption index of the surface layer as reffered to above. Two desorption process types of the surface layer depending only on desorping duration, shown by the h₃₀ index, may be found after some arrangement of all desorption processes in the year (1977) (Fig. 5). Both are for winter (Nov. 15 to Mar. 15) and other seasons. Tabulation of desorption classified by the desorbing duration and precipitation before desorption shows frequencies and levels of desorption easiest to occur in this district (Table 4).
The boundary layer between upward and downward flow are changeable, but never exceeded over 100cm depth throughout the year. Therefore, soil water always flows downwards in layers below 100cm (Fig. 8).
1.4mm/day was computed for average yearly downward discharge from a bare surface layer through the Darcy, equation with a pseudohysteresis loop using retentivity and conductivity measuements. 1.3 to 3.0mm/day is also for average yearly downward discharge in the deep Shirasu layer near ground water table through the Darcy computation using retentivity measurements from the water content data sampled, from thinwall sampler boring fractions. Both results are fairly compatible with the computed result on ground water balance in this platform in the following paper.

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Movement of ground water and spring water in the Tsukabaru Shirasu terrace in Miyazaki Prefecture into which no influx is considered negligible from the outside the area is investigated in an attempt to understand the water circulation through the terrace. The followings are the summarized results
1. Ground water begins to rise from the shortest distance between the ground surface and water table during the water increasing period, and begins to fall from the thickest and highest part of the aquifer during the depletion period. Changes in the water table are classified into three groups according to depth and precipitation patterns (Figs. 3, 4 and 5, respectively):
a) Water table found between ground level and three meters, which quickly responds to dirnal rainfall patterns.
b) Found at depths of between 5 and 13 meters in response to monthly rainfall patterns.
c) Found at a depth of over 13 meters, which shows some small variations due to seasonal rainfall patterns.
2. Stored water in aquifer shows an insignificant change in quantity of between 1, 150 and 1, 200mm during the observed period (1976 November to 1979 July) due to the large 35% value in the specific yield of the Shirasu layer (Fig. 7).
3. Geographical distribution of springs has a certain principal tendency, but intensive locality appears simultaneously. This is because the ground water flow depending on superficial outline of nonpermeable layer (the Tertiary) submits intensity of spring efflux (Figs. 9 and 11).
4. Changes in spring efflux are subject to those of the water table behind the springs. So, the topographical features of the ground surface, which extend to the interior of the terrace, must be examined in detail, as well as the features of ground water as they stands, in order to establish clearly the movement of the spring water efflux (Figs. 2 and 10).

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Evaporation Y (mm/day) from Kuroboku soils where the second layer was Akahoya soil or Bora soil was measured using a soil tank (ground-water recharge type), and evaporation from the water surface was measured using an evaporation tank (large type).
Net radiation, X (ly/day), was measured at the same time. The relation between Y and X were obtained as follows:
In a period from the first 10 days of August until the same period of October,
Y=0.0114X+1.39: where soil layers were Kuroboku-Akahoya
(r=0.815)
Y=0.00812X-0.139: where soil layers were Kuroboku-Bora-Kuroniga
(r=0.776)
Y=0.0133X+0.0394: at the evaporation tank
(r=0.844)
Howewer, correlation was not very good from about the 10th of October until the latter part of November, due to air movement and temperature ranges (see Figs. 2-4).
The influence of the Bora soil layer on evaporation judged from the evaporation ratio was a reduction of evaporation to about 0.5-0.6 (see Table 1).
Changes of soil temperature with time showed a similar tendency. But, when the second layer was Bora soil, it was 1-2°C higher than when it was not Bora soil, and the time-lag at the highest temperature in each depth of soil was smaller than when the second layer was Akahoya soil (see Fig. 5).
Changes of total potential with time were larger when the second layer was Bora soil. However, there were small changes every 50cm down (see Fig. 6).
Values obtained by the foregoing method, using a soil tank (ground-water recharge type), on Kuroboku soil with a second layer of Akahoya soil were close to the values obtained when the heat balance method or PEBYT's method was used. But, they were larger when this method was used on Kuroboku soil with a second layer of Bora soil as shown in Table 2.

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This paper considers the composition of water in soil structure.
Some volcanic ash soil samples (Kuroboku, Akahoya, Kuroniga and Shirasu) in different stages of pF (pF=0, 1.0, 2.0, 2.5-3.0, 5.5) were investigated by means of an optical microscope and a scanning electron microscope. Those samples investigated with the scanning electron microscope were used as the freezing state.
The pF values of the soil water kept in a continuous pore were smaller than 2.0. The water covering the surface of soil particles had a pF value of about 3.0 or over.
The experiment clearly showed that the amount of soil water, caused by the energy from pF2.0 to 3.0, was less than the others, and this corresponded to the distribution of pores which were observed in a piece of the soil that was sliced off as a sample.

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The condition of surveyed area was described in previous paper (part 1), in which 38 different experimental sites (with different physical and chemical characteristics) were treated for soil desalinization and land reclamation survey. In part 2, data obtained concerning soil salinity were treated statistically.
The summary of the detailed studies is as follows;
(1) Most of the salts in the survey area were sulfates and chlorides of calcium, magnesium and sodium with a high degree of solubility which could be leached out easily.
(2) Low soil intake-rate, very shallow-shallow ground water-table, and/or the heaviness of the second soil layer or their combination effect were restricting factors for soil pH decreasing. But the presence of calcium and gypsum in the soil acted to prevent efficient increase in the alkalinity.
(3) Using the Shavour river's water for leaching, however, the soil texture was very heavy. But in the project, desalinization and reclamation of saline and saline-alkaline soils could be done successfully.
(4) Lowering the saline ground-water table by means of a drainage system and improvement. of soil intake-rate might be helpful to decrease the soil pH.
(5) Chemical amendment application and leaching may improve both physical and chemical characteristics of the soil if the ground-water table is controlled below 1.5 meters.
(6) The changes of salinity and alkalinity were different with depth of percolated water. In this case an optimum practical depth of leaching water should be found and applied.
These will be the indications of our next papers.

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The ultrasonic pulsating method is useful for inspecting the physical properties of mortar and concrete specimens.
In the first paper of this series, the authors estimated the change in properties regarding mortar and concrete specimens by using the characteristics of ultrasonic pulses propagated under uniaxial compressive loading.
Especially, the relation between the ultrasonic pulse velocity (V_p) and the progress of breakage (inelastic volumetric strain:Δε_ν) were discussed in detail.
The present paper deals with the attenuation of ultrasonic pulses propagated through mortar and concrete specimens, and the results are compared with those of another nondestructive testing experiment (A. E. method) and with the results obtained from the previous paper in this study.
The results obtained are as follows.
1) For the specimens undergoing deformation, the change in the amplitude ratio (A/A₀) was affected much more than that of the velocity ratio (V_p/V₀) with a change between the condition of ultimate stress and that of a complete breakdown.
2) In the same as the attenuation coefficients of the ultrasonic pulses propagated to a direction perpendicular to specimen's axis, the A. E. count rates increased with an increase in the inelastic volumetric strain (in the microfracturing zone).
3) In the comparison with the value of the propagation velocity within the cracking zone, it seems that the value of the attenuation coefficient, which was calculated from the propagation velocities and the amplitudes of the ultrasonic pulse, is a much more effective index for inspecting the mortar and concrete materials under uniaxial compressive loading.

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The purpose of this study is to determine quantitatively the dynamic deformation characteristics of soil structures with a slope such as fill dams. We performed dynamic triaxial tests on saturated Toyoura Sand applying initial shear stress, then we used the test results to determine shear modulus G and damping ratio D used in the equivalent linear method, taking account of the effects of initial shear stress.
As mentioned in the previous papar, plastic shear strain significantly increases, particularly in the fi rst 10 cycles of sinusoidal dynamic load, after applying initial shear stress. Thus, the starting and the end points on the hysteretic curve in each cycle do not coincide. In order to take account of the effect of more dissipated energy due to applying initial shear stress, we indicated the definition of the two parameters G and D according to the actual hysteretic curve.
As a result of considering the quantitative determination of G and D, we obtained the following conclusions: shear modulus ratio G/G_o (in which G_o is the shear modulus with a very small shear strain amplitude) can be determined by the function of [G/G_o] p'=1 which is the value of G/G_o at effective mean principal stress p'=1.0 kg/cm² and m'(γ_a) which is the power of p'; furthermore, damping ratio D can be determined by the quadratic function of G/G_o. It is seen from the comparison among the curves of the relationships [G/G_o] p'=1-γ_aa and D-G/G_o by the authors and those by the other investigators that the difference among those curves is rather small, but that the curve D-G/G_o by the authors gives greater values of D than the curves by the other investigators.
Next, it seems from the test results that the effects of initial shear stress clearly appear in the dynamic deformation characteristics with only a small number of cycles and the anisotropic structure of soil due to initial shear stress is gradually changed by repeated loading into a rather isotropic structure. So, we consider the variation of G and D with increase of the number of cycles. It is concluded that the change of soil structure influences considerably for D but a little for G. Finally we compare the curve of the relationship [G/G_o] p'=1-γ_a established by the authors with that by Shibata and Soelarno which was obtained in an isotropic stress condition using the same material and the same type of apparatus as used in this study. It is seen that [G/G_o] p'=-1 applied initial shear stress is smaller than that in the isotropic stress condition for γ_a when less than 10^-3, but that almost of them agree when larger than 10^-3. This may be due to the fact that the anisotropic structure of soil due to initial shear stress reduces G/G_o with a small shear strain amplitude, but that this effect disappears as the anisotropic stucture approaches a rather isotropic structure with a large shear strain amplitude.

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Land classification is one of the most fundamental methods for land-use classification, but it is not used very much in practical zoning.
In this paper, we explained the meaning and the limitation of land classification in zoning, and then designed the method of land-use classification on the land classification, and examined it by applying it to practical areas.
This method is as follows:
(1) A planning area is a village, and zones for land-use classification are for agricultural use in large scale, for agricultural use in small scale, and for non-agricultural use.
(2) First, the zone of land for agricultural use in large scale is determined by the amount of need, secondly the land classification of land for agricultural use in small scale is applied on the remaining land, and land at the lower rank is set up for non-agricultural use, and then the remaining land is set up in a zone of land for agricultural use on a small scale.

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