DETERMINATION OF SEISMIC ANISOTROPY OF METAMORPHIC ROCKS IN NATURAL CONDITIONS

Anisotropy of seismic wave velocities in schists is measured in natural conditions. The detected values of the anisotropy (P wave) are found to be 10-20%. The results are discussed in comparison with the supersonic method for the rock specimens

In Situ Determination of Variation of Poisson's Ratio in Granite Accompanied by Weathering Effect and its Significance in Engineering Projects

At first, the practical method for the generation of S wave was examined in the adit. A small explosion in a drill hole was mainly used as its wave source. The small explosion can be approximately considered as the single force referring to the effect on the generation of S wave. Secondly, real measurements were carried out in order to determine the ratio (α) of P wave velocity (V_p) to S wave velocity (V_s) in granite. It was approximately expressed by the following formula. α= - 0.49V_p + 4.34 where V_p 〔km/sec〕 is the value which varies by the weathering effect. It is suggested by this result that the well-known discrepancy between dynamic Young's modulus and static Young's modulus, in situ, can be explained by neglecting Poisson's ratio variation in the estimation of dynamic Young's modulus, and partly by insufficient evaluation of the velocity lowering in the adit wall

CALIBRATION OF HIGHER FREQUENCY CHARACTERISTICS OF GEOPHONE

In this paper the author developed the new method to calibrate the geophone characteristics in the higher frequency range, where exact measurement can not be assured by all most all methods developed in usual lower frequency range. When the longitudinal wave propagates along one dimensional bar, we can evaluate its particle velocity by detecting its strain. Using this principle, we detect the vibration velocity of the geophone body (to be, tested) attached to the end of the bar. The merit of this method is that we can check the setting condition of the geophone by evaluating the reflection coefficient of the wave at the geophone end. By this method the author could calibrate the frequency characteristics of geophones up to 3000 or 4000 cps

Sハオヨビコレニカンレンスルショモンダイニツイテノヤガイジッケンテキケンキュウ

京都大学0048新制・論文博士理学博士乙第1954号論理博第380号新制||理||155(附属図書館)3194UT51-47-B471(主査)教授 小沢 泉夫, 教授 吉川 宗治, 教授 三木 晴男学位規則第5条第2項該当Kyoto UniversityDA

FIELD-EXPERIMENTAL STUDY OF SHEAR WAVE AND THE RELATED PROBLEMS

The author has been engaged in field-experimental studies of S waves since 1957. In this paper, he discusses fundamental aspects of the S wave from field-experimental point of view, giving systematic form to his previous works. In an earlier part of this paper, problems of detection and generation of S waves are discussed, and they are connected to the methods of S wave logging in the later part. Significance of tube wave velocity and resistivity logging are emphasized as an indirect method of S wave logging. Results of experiments suggest that both are favourable for the purpose of S wave logging. From the resistivity logs void ratios are deduced, and the relation between S wave velocity and void ratio are compared with Hardin's relations obtained by laboratory experiments. Both agree in the main essentials. Velocity variation of weathered granite, obtained in field experiment, is dicussed in connection with sample tests by other authors. Empirical relations between P and S wave velocities are presented to the system covering granular soil and siliceous rock. In the final section, significance and methods of S wave logging are discussed in connection with earthquake engineering