巻号一覧
3 巻 (1950 - 1951)
- 2 号 p. 44-
- 1 号 p. 7-
前身誌
3 巻, 1 号
選択された号の論文の6件中1～6を表示しています
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鈴木 次郎1950 年 3 巻 1 号 p. 7-10
発行日: 1950/11/30
公開日: 2010/06/30
ジャーナル フリーThe Problem has long been discussed whether S waves are propagated through the earth's core. For contributing to the solution of the above problem and estimating the allowable upper limit of rigidity of the earth's core as well, some considerations and computations by the aid of a simplified model have been made.
Results are:
(1) waves'reported as S′ so far, being reconsidered from the results of computations of travel-time and amplitude, cannot be interpreted as S′.
(2) The rigidity of the earth's core cannot be greater than 109 c. g. s.抄録全体を表示PDF形式でダウンロード (208K) -
淺田 敏, 鈴木 次郎, 友田 好文1950 年 3 巻 1 号 p. 11-15
発行日: 1950/11/30
公開日: 2010/06/30
ジャーナル フリー1) Gutenberg and Richter studied frequencies and magnitudes of earthquakes and obtained the following relation establishing a relationship between magnitude and energy released annually by earthquake waves (NE),
logNE=18.7+0.9M. (1)
This relation shows that “NE” becomes greater as M becmes bigger. And they concluded that smaller shocks almost never were sufficiently frequent to approximate the energy, released in larger shocks. This conclusion is, of course, not wrong, so far as the Richter's Magnitude-scale is concerned. But if E is adopted instead of M, the above formula is transformed into the following one,
logNE=cont.-0.5logE. (2)
This shows that the energy released annually by larger shocks is smaller than that by minor shocks. This seeming contradiction between (1) and (2) is due to how the magnitude is measured, by M or by E.
2) Kawasumi's results on energies and frequencies of earthquakes derived from the data of earthquakes in and near Japan fairly agree with those by Gutenberg and Richter.
3) The Ishimoto-lida's formula, n(a)da=ka-mda, can be changed into a formula, logN=cost.-bM, under some suitable assumptions. If m is 1.9, the value of b is 0.9.
4) The energy of the smallest micro-earthquakes observed by the present authors is of the order of 1010 erg. which is about 1/100 of that of the minimum earthquake observed by Richter and Nordquist. The Ishimoto-Iida's formula holds good even for such small earthquakes.抄録全体を表示PDF形式でダウンロード (261K) -
久保寺 章1950 年 3 巻 1 号 p. 16-21
発行日: 1950/11/30
公開日: 2010/06/30
ジャーナル フリーThe writer studied the surface-waves (Rayleigh-type) generated by artificial earthquakes, especially in regard to the attenuation of amplitudes with the increase in focal distances and calculated the attenuation coefficient from the data obtained by himself.
Next, the data were compared with his modified Sezawa's theory and the viscosities of the weak surface layers were calculated.
Finally, the writer discussed the relation between earthquake damage and mechanical properties of the weak surface layers.抄録全体を表示PDF形式でダウンロード (257K) -
吉山 良一1950 年 3 巻 1 号 p. 22-26
発行日: 1950/11/30
公開日: 2010/06/30
ジャーナル フリー1. The seismograms of the Nanakaido Earthquake were of very complicated appearance-Accordingly, the determination of Pn, P*, P and S were made in many different ways. Taking these interpretations into consideration, the author studied how wide the epicentral area had extended and how the earthquake had occurred.
2. Seismometrical results of the Nankaido Earthquake and one of its after-shocks having occurred Apr. 18, 1948 were compared with each other. Some considerations were also made as to their epicenters.
3. The amplitudes of initial motion of the above two earthquakes were studied. It was revealed that the two earthquakes had occurred in much the similar way.
4. A question was presented what should be meant by an earthquake.抄録全体を表示PDF形式でダウンロード (310K) -
高木 聖1950 年 3 巻 1 号 p. 27-31
発行日: 1950/11/30
公開日: 2010/06/30
ジャーナル フリーAlthough it has been already 27 years since the Great Kwanto Earthquake, yet no decisive conclusion has been obtained as to the mode of distribution of initial motions due to that earthquake. After recollecting several theories on the problem, the author comes to the conclusion that the distribution of initial motions is likely to be well interpreted by means of the so-called conical type rather than by the quadrant type. The vertical angle of the cone is 120° and its axis inclines 8° to the East from the vertical line.
Furthermore, the epicenter of the earthquake was found to be near Mt. Tanzawa with a depth of 45 kilometers.抄録全体を表示PDF形式でダウンロード (304K) -
北澤 五郎1950 年 3 巻 1 号 p. 32-35
発行日: 1950/11/30
公開日: 2010/06/30
ジャーナル フリーThe writer introduced the coefficient γ=1/Σδh in order to indicate the degree of solidity of the ground in his previous paper.
In that paper, the coefficient γ was compared with the percentage of totally collapsed wooden houses in case of the Great Kwanto Earthquake. In the present paper, γ is compared with damage to reinforced concrete buildings caused by the same earthquake.
Degree of damage and coefficient γ are related linearly referred both to wooden and reinforced concrete structures. Hitherto, the distribution of seismic intensities of an earthquake in different localities has been figured out by investigating the damage to structures. Therefore, the result obtained in this way is strongly influenced by the strength of structures. The coefficient γ on the other hand depends upon the geological structure alone, and the determination of seismic intensity based upon γ would be more reasonable and exact.抄録全体を表示PDF形式でダウンロード (168K)
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