Relation between chemical and physical weathering of andesite has been studied on rock pieces of various stages of weathering. Chemical analysis on the same rocks measured physical properties was performed by atomic absorption spectroscopy method. Results obtained in this study are summarized as follows: 1) As a whole, considerable correlation is recognized among chemical weathering index of SiO2/(Al2O3+H2O+) mole-ratio and physical properties, as indicated by Fig. 5 and Fig. 7. 2) Chemical analysis for estimation of chemical weathering indices require the delicacy and skill, and does not expected to be so accurate as physical properties because of inhomogeneity of rocks. 3) If the chemical analysis is limited to weathered rocks which can be prepared a specimen for the compression test, distribution of values of the chemical weathering index is of narrow range, in comparison with its accuracy, than that of physical properties.
Image processing and automatic analysis are the latest trends in geological interpretation of aerial photograph, with the development of remote sensing technique. But the results are not always satisfied, because the quantitative relations connecting the imagery to geology have been left unsolved, which give the computer some numerical standards of judgement. The use of drainage pattern, one of the most important factors obtained from imagery, should be acceptable at first in order to systematizing these standards. Some drainage areas of different lithofacies were selected here, and stream-order was distinguished and put down on the topographic map in each area. And each area was divided into small area (about 250×250m in section). Then some stream varialbes such as number, length, area and inclination of stream were measured in the same stream-order in each section on the map, and each lithofacies could be represented numerically as the multidimensional center of grabity with statistical values as mean vector of stream variables. Discriminant analysis with nonlinear discriminant function in the basis of Maharanobis' generalized distance was used here to distinguish some lithofacies. As the result, each lithofacies selected here was statistically discriminated by combining some stream variables of the same order, and more over some differences estimated to be affected by weathering and geological structure were recognized in case of similar facies. Then we could have some prospect to systematize the geological interpretation with the quantitative relation between geology and drainage pattern by accumulating these kind of data and adding the investigation for genetic relation of them
This report describes the result of geological survey and the initial in situ stress measurement in the Shintakase-gawa Underground Poworhouse. As the result, it has been found that the tectonic stress inferred from the cojugate fault, has been in close agreement with the initial in situ stress measured by the overcoring method.
In the landslide area of Sendai district, Miyagi Prefecture, the Pleistocene formation of the Aobayama stage covers the underlying Pliocene and Miocene deposits; and unconformity is observed in the formations of this area. The degree of unconformity in the landslide area is determined by the greatness of the geologic movements. We examined the compressibility of many specimens of sedimentary rocks gathered from the neighborhood of the unconformable part which forms the boundary between the overlying and the underlying strata in the formations of this area. A classification scheme illustrates three grades and two types of compressibility which have resulted from chemical and mechanical weathering. From this, a study was made of the influence of crustal movement upon landslides; besides, the volume of sedimentes was esimated, basing the estimation upon preconsolidation pressure. In conclusion, the mechanism of the present landslide is strongly controlled by the crustal movement which was formed in geologic eras, and a remarkable relation is observed between unconformity and crustal movement which is indicated by fault and folding.