巻号一覧
23 巻 (1970)
- 4 号 p. 253-
- 3 号 p. 191-
- 2 号 p. 99-
- 1 号 p. 1-
前身誌
23 巻, 4 号
選択された号の論文の9件中1～9を表示しています
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塩野 清治1970 年 23 巻 4 号 p. 253-263
発行日: 1970/12/28
公開日: 2010/03/11
ジャーナル フリーOn the bases of the fault plane solutions that have been obtained in the first paper, a statistical study has been made on the state of stresses that generated those earthquakes and the types of faultings both for the shallower earthquakes (H<20km) and the deeper earthquakes (H≥20km) in Wakayama region.
The average direction of P axes (the maximum pressure axes) for the shallower earthquakes was oriented horizontally along N 122.9°E direction. It has been inferred that the shallower earthquakes in Wakayama-Arida region showed components of thrust faultings and the stress state in this region might be σ1>σ2≈σ3 and that the shallower earthquakes in Hidaka region were characterized by strike slip faultings.
Because number of the fault plane solutions of the deeper earthquakes was 23, we could not discuss in detail the stress state in the upper mantle of this region. But the solutions of 23 earthquakes have suggested that the T axes (the maximum tesion axes) might change their orientations from E-W to NE-SW according to the shift of their location from the Kii channel to the central part of the Kii peninsula and that the P axes might be in the N-S direction in the Kii channel and be in the same direction as that of the P axes of the shallower earthquakes in the central part of the Kii peninsula.抄録全体を表示PDF形式でダウンロード (939K) -
野越 三雄, 五十嵐 享1970 年 23 巻 4 号 p. 264-280
発行日: 1970/12/28
公開日: 2010/03/11
ジャーナル フリーFundamental natures of microtremors have already been discussed by many investigators. The grouth mechanism of microtremor is not yet known. In this paper, the propagation characteristics of microtremor was investigated. The experimental field is Hakodate City in Hokkaido.
The propagation of microtremor was confirmed from the tripartite observation, and by the orbital motions, directions and velocities of microtremors, it was found that these waves were Rayleigh type wave, Love type wave and a combination of both. Phase velocity observed at the place where confirmed the propagation of microtremors agreed partly with the dispersion curves of fundamental mode of Rayleigh and Love wave. A ditch with a depth of 1m was made at the place confirmed the propagation of microtremor. However, it didn't affect the vertical component of microtremor. Nextly, microtremors were observed on the moat with a depth of 3m at Goryokaku in Hakodate City, by means of tripartite and 3-component observation.
From results of observation, it was found that the attenuation of the frequency characteristics of microtremors with vertical component between two places across the moat were more rapid with higher frequency and microtremors on the isolated island around the moat were only composed of Love type waves. The attenuation of energy ratio for k(wave number)×d(depth of the moat or slit) in case of the moat was well in accordance with results of model experiments which made in order to show the attenuation of Rayleigh wave for a slit. From a point of view of the propagation characteristics of microtremors, the vertical component of microtremors may be almost composed of Rayleigh wave.抄録全体を表示PDF形式でダウンロード (1286K) -
野越 三雄, 五十嵐 享1970 年 23 巻 4 号 p. 281-303
発行日: 1970/12/28
公開日: 2010/03/11
ジャーナル フリーThe amplitude characteristics as the fundamental natures of microtremors was discussed at the present paper. The experimental field is Hakodate City in Hokkaido.
The random physical phenomena of microtremors were treated as the stationary random process. In order to express the amplitude characteristics of microtremors, power spectral density functions were therefore computed. The statistical check of the amplitudes microtremors was used by means of χ2-test.
Theoretical amplitude characteristics from the underground structure is the frequency of the minimum group velocity of L0- and M11-wave and the amplitude ratio by the theory of multiple reflection. They were compared with the predominant frequencies of power spectral density functions of microtremors.
From the point of view to remark only the predominant frequency at the amplitude characteristics of microtremor, we may conclude from these comparisons that the horizontal component of microtremors can be treated as the amplitude characteristics of the amplitude ratio from S-wave structure or the fundamental mode of Love wave at the places where the boundary of the subsoil and basement is district. However, the amplitude characteristics of the vertical component of microtermor never agrees with the amplitude ratio from P-wave structure, and it agrees or not with the amplitude characteristics of the fundamental mode of Rayleigh wave.
Furthermore, the spectra of waveform by explosion seismic observation was compared with the amplitude characteristics from the theory of multiple reflection, the minimum group velocity of surface wave and the power spectra of microtremor.抄録全体を表示PDF形式でダウンロード (1546K) -
菊地 正幸, 竹内 均1970 年 23 巻 4 号 p. 304-312
発行日: 1970/12/28
公開日: 2010/03/11
ジャーナル フリーFollowing the way developed by KOSTROV (1966), we discuss the problem of longitudinal shear crack propagation. A formal solution for an arbitrarily given shear stress drop p(x, t along the crack was obtained previously (TAKEUCHI and KIKUCHI, 1970). In the present paper, making use of this solution, we worked out the case of p(x, t)=const=τ0, i. e., the constant shear stress drop. According to our numerical computations, the fracture velocity increases with the time to its final value VS, shear wave velocity in the medium, when Lτ02/μT≥2.0, where L, τ0, μ and T are initial length of the crack, shear stress drop, rigidity and surface energy, respectively. This condition may be compared with the Griflith condition Lτ02/μT≥2.55 in the corresponding statical problem. It is known by the analysis of seismic surface waves that in the Chilean earthquake in 1960, a fracture of total length of about 1000km propagated with nearly S-wave velocity. We can apply our results in the present paper to this earthquake and estimate the maximum value of T and the minimum value of L. The results, together with the similar results, are shown in Table 2 and 3.抄録全体を表示PDF形式でダウンロード (557K) -
竹内 均, 小林 直太, 園部 雅之1970 年 23 巻 4 号 p. 313-320
発行日: 1970/12/28
公開日: 2010/03/11
ジャーナル フリーMaking use of composite materials composed of the epoxy-resins as matrix and small iron balls or powders as inclusion, we measured the bulk density and the bulk S wave velocity, and then calculated the bulk rigidity of them. We then compared the experimental results with the ESHELBY'S theory on the bulk elastic constants of composite materials. The agreements between them are quite satisfactory.抄録全体を表示PDF形式でダウンロード (2098K) -
伊神 輝, 飯田 汲事1970 年 23 巻 4 号 p. 321-331
発行日: 1970/12/28
公開日: 2010/03/11
ジャーナル フリーThe time variation of earthquake volume was investigated from the spatial distribution of aftershocks of both Tohnankai earthquake (1944) and Mikawa earthquake (1945). As these two great earthquakes occurred during the period of the World War II, there were not sufficient data which were published, but the available data concerning the aftershock activity were obtained by virtue of Nagoya Meteorological Observatory. Owing to these collected data the magnitude of all aftershocks were calculated by using the duration of preliminary tremors and the duration of oscillations. Thus the time variations of both released seismic wave-energy and energy-density were obtained.
It was found that the released wave-energy density varied from 1×104erg/cm3 at the time soon after the main shock to 4×103erg/cm3 at the time after one year passed in the case of Tohnankai earthquake and from 6×103 erg/cm3 to 1×103erg/cm3 in the case of Mikawa earthquake.抄録全体を表示PDF形式でダウンロード (740K) -
嶋 悦三, 柳沢 馬住, 工藤 一嘉1970 年 23 巻 4 号 p. 332-334
発行日: 1970/12/28
公開日: 2010/03/11
ジャーナル フリーPDF形式でダウンロード (1885K) -
竹内 均1970 年 23 巻 4 号 p. 334-335
発行日: 1970/12/28
公開日: 2010/03/11
ジャーナル フリーPDF形式でダウンロード (226K) -
神田 茂1970 年 23 巻 4 号 p. 335-336
発行日: 1970/12/28
公開日: 2010/03/11
ジャーナル フリーPDF形式でダウンロード (135K)
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