巻号一覧
27 巻 (1974)
- 4 号 p. 285-
- 3 号 p. 185-
- 2 号 p. 95-
- 1 号 p. 1-
前身誌
27 巻, 3 号
選択された号の論文の11件中1～11を表示しています
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関谷 溥1974 年 27 巻 3 号 p. 185-196
発行日: 1974/09/30
公開日: 2010/03/11
ジャーナル フリーThe rumble of houses occurred at Hashida area in Kagoshima prefecture, Takawashi area in Gifu prefecture and Makado area in Shizuoka prefecture, from June through July, 1972. These phenomena had occurred at Hukumitsu area in Toyama prefecture, at the foot of Hakusan national park, from 27 December 1958 through April 1959. According to a field investigation, the type of these shocks was continuous one just like vibrations of motors. The felt area was restricted within narrow limit of 1 or 2km, near a check dam at a river gorge. But no recordings of these phenomena at Hashida, were found on the seismogram (V=10μkine/mm).
The author investigated the mechanism of these pheomena. These shocks started to occur, just after when the check dam at the river overflowed with water by heavy rainfall or melting snow. As a result, it was found that the abnormal shocks occurred with air vibration by a water curtain which fell from the dam, and the energy was about 105 erg per second. Thus, the prediction of shocks which occur on a fixed check dam is feasible to some degree. But, the author believes that a special attention should be paid for eliminating the causes of the phenomena in designing new check dams.抄録全体を表示PDF形式でダウンロード (2992K) -
藤井 陽一郎1974 年 27 巻 3 号 p. 197-214
発行日: 1974/09/30
公開日: 2010/03/11
ジャーナル フリーBased on some examples of the vertical crustal movenent accompanied with earthquakes, the detailed phases of a cycle of seismic crustal movement are formulated as follows,
α: steady state movement
β1: state of dilatancy
β2: unstable movement following β1 phase
γ1: pre-seismic slip
γ2: co-seismic slip
γ3: post-seismic slip
δ: transient state movement.
The crust is deformed lineary with time under tectonic stress field (α phase). After the accumulation of strain, the multiplication of cracks starts (β1 phase). The unstable and pulsative movement follows to the β1 phase (β2 phase). The β1 and β2 phases might correspond to the stress concentration around the future slip plane. Just before the earthquake, the pre-seismic slow slip may be caused on the fault plane (γ1 phase). At the time of earthquake, rapid slip on the fault plane emits the elastic waves(γ2 phase). Following the earthquake movement of β and γ phases, the transient phase may be caused under tectonic stress (δ phase).
Analysing the selected eight examples of precursoy crustal movement, duration period of β1 and β2 phases, that is, the period from the start of anomalous crustal movement to the occurence of earthquake, are estimated. There exists a relation between the estimated duration period t and the magnitude of earthquakes M:
logt(year)=0.52M-2.80.
On the other hand, the equated radius r of anomalous crustal movement is expressed as
logr(km)=0.51M-2.27(Dambara, 1966).
Then, the duration period of anomalous crustal movement and the radius of anomalous area seems to be in linear relation, r=3.4km/year·t.
This fact can be interpreted as follows. As anomalous crustal movement appears, the dilatancy starts from nucleus points or lines in the area and grows out with the constant velocity of several kilometers per year. The existence of this kind of propagation can be assumed from the equation of diffusion in the theory of porous medium. Finally the dilatancy will fill up some volume, which may correspond to the earthquake volume. The author discussed in other paper the horizontal propagation of precursory movement in case of the Niigata earthquake of 1964, and found that the velocity of expansion is 2-3km/year in its beginning and 10km/year in the last. This observed velocity shows a good coincidence with the derived value mentioned above.抄録全体を表示PDF形式でダウンロード (1245K) -
大脇 潮1974 年 27 巻 3 号 p. 215-224
発行日: 1974/09/30
公開日: 2010/03/11
ジャーナル フリーThe map of expected maximum acceleration in Japan was published in 1951 by Kawasumi based on 342 data during 1350 years. Muramatu computed in 1966 the expected maximum veloctiy using 106 data during 97 years. These two, however, are not so well coincident with each other. The discrepancy may be partly due to the difference in time duration of data. The older the data, the less precise the quality in number and homogeneity of distribution.
In this paper the similar study on expected intensity is made based on the homogeneous and high quality data by JMA during 1926 and 1965. The average intensities at 552 mesh points are calulated. The result for whole 40 years (L) has a good correlation with that for every 10 years (A, B, C, D).
The correlation between the present result and those based on longer period data is also found, although the correlation is not so high as the case of L, A, B, C and D. These results indicate that the expected intensity based on the short time data is fairly useful, if the data are homogeneous and of high quality.抄録全体を表示PDF形式でダウンロード (794K) -
西南日本における High-Q Zone の存在伊神 輝, 伊藤 潔1974 年 27 巻 3 号 p. 225-238
発行日: 1974/09/30
公開日: 2010/03/11
ジャーナル フリーSeismograms comprise a wide variety of oscillations. Although there are many factors which give rise to this variety, we payed attention to only the effect of ray paths on seismograms. The seismograms recorded at the Inuyama Seismological Observatory (INU: 137°01′42″.8E, 35°20′58″.8F, Alt. 132m) were analysed.
The seismic waves traveled from southwest Japan to INU were less attenuated than those from another regions in and near Japan. In view of this fact, we ascertained the existence of a high-Q zone in southwest Japan. This high-Q zone was conceived by the detectability of the event at INU, too. This high-Q zone may be attributed to the stence of the Philippine Sea plate. It has been also inferred from the analyses of mechanisms of the great earthquakes that the Philippine Sea plate is downthrusting beneath the Nankai trough. From the detectability, we found another important fact suggesting that, in the south part of Chubu district, there is a zone of a very-low-Q value, which is located at a depth shallower than that of the Philippine Sea plate.抄録全体を表示PDF形式でダウンロード (5097K) -
田中 寅夫1974 年 27 巻 3 号 p. 239-245
発行日: 1974/09/30
公開日: 2010/03/11
ジャーナル フリーTheoretical tilts and strains that would be expected at Oura, Wakayama from the Chilean tsunami of May 24, 1960 have been calculated according to the KUO's theory of a multilayered medium and the Green's functions given by FARRELL, using the tidegauge records at the coasts of the Kii Channel, Osaka Bay and others. The E18°S-W18°N component of the calculated tilts agrees well with the observed ground tilt, which shows that this component is successfully explained as the loading deformation of the Gutenberg-Bullen A model earth. The other component of tilts and two components of the calculated strains show remarkable discrepancies against the observed results, the circumstances of which are very similar to the case of the earth tidal phenomena at Oura. The discrepancies may be due to topographical situations of the station and/or some local origins such as the stress concentration around the observing vault.抄録全体を表示PDF形式でダウンロード (2281K) -
大井田 徹, 伊藤 潔1974 年 27 巻 3 号 p. 246-261
発行日: 1974/09/30
公開日: 2010/03/11
ジャーナル フリーFocal mechanism solutions have been determined for 113 shallow earthquakes which occurred from 1968 to 1971 in the east part of Kinki district and Chubu district, Central Honshu, Japan. These mechanisms have been obtained from the first motion of P waves recorded by the stations of Japan Meteorological Agency (J. M. A.) and microearthquake observation stations. Mechanisms have been determined for the earthquakes with magnitude as small as 2.5.
Although the local variation of pressure direction becomes larger, the smaller the earthquakes become, almost of the pressure directions obtained in this study agree well with those of the major shocks analyzed by many seismologists. But there exists a remarkable contrast of the pressure directions in the southwest of Chubu district (Mikawa district and Ise Bay), where pressure lay east-west in the crust but south-north in the upper most mantle. Similar results were obtained in the Kii straight and the south part of Shikoku by SHIONO (1970) and SAWAMURA and KIMURA (1971), respectively. These facts can be interpreted by assuming the pressure which lay perpendicular to the Nankai Trough and the subsedence of the Philippine Sea plate.抄録全体を表示PDF形式でダウンロード (8409K) -
岡野 健之助, 梅田 康弘1974 年 27 巻 3 号 p. 262-269
発行日: 1974/09/30
公開日: 2010/03/11
ジャーナル フリーAn underground observation vault was established at Abuyama Seismological Observatory in 1971. The crustal deformation has been observed for about two years by silicatube extensometers, horizontal pendulum and water-tube tiltmeters installed at this vault. It is noted from this observation that the ground has extended in the EW direction and contracted in the NS direction. This direction of ground deformation is contrary to that inferred from the mechanism of earthquakes occurring in the vicinity of the observatory. The ground deformation observed may result from the direction of the strike of NS-N20°E around the vault.抄録全体を表示PDF形式でダウンロード (698K) -
笠原 順三1974 年 27 巻 3 号 p. 270-272
発行日: 1974/09/30
公開日: 2010/03/11
ジャーナル フリーPDF形式でダウンロード (314K) -
竹内 均1974 年 27 巻 3 号 p. 273
発行日: 1974/09/30
公開日: 2010/03/11
ジャーナル フリーPDF形式でダウンロード (143K) -
竹内 均1974 年 27 巻 3 号 p. 274
発行日: 1974/09/30
公開日: 2010/03/11
ジャーナル フリーPDF形式でダウンロード (154K) -
―1972年10月6日伊豆半島南西沖地震―石橋 克彦1974 年 27 巻 3 号 p. 275-278
発行日: 1974/09/30
公開日: 2010/03/11
ジャーナル フリーPDF形式でダウンロード (415K)
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