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Volume 4, Issue 2
Displaying 1-9 of 9 articles from this issue
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Setumi MIYAMURA, Masaru TSUJIURA1951 Volume 4 Issue 2 Pages 48-50
Published: December 30, 1951
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSPor transdoni samtempe ekzaktajn tempo-signalojn de unu norma horlogo al apartaj sismaj observejoj, kaj fari parolan komunikadon inter la observejoj, precipe en la okazo de post-tertrema observado, ni projektas uzi altfrekvencan telefonadon tra la funkciantaj privataj fadenoj de elektraj kompanioj. (Frekvenco de portanta ondo estas 100-200kHz.)
La lastaj eksperimentoj tra cickau 27km nuda telefon-fadeno de Kvanto Elektro-livera Kompanio inter Hanabata kaj Tudanuma, ambau cirkau-urboj de Tokio, montris, ke ni povas akiri konstantan transdonon de tempo-signaloj kaj klaran parolkomunikon per niaj aparatoj, sen malhelpi samtempe la funkcion de ordinala parol-telefonado.
Plie, ni diskutas pri profitoj de nia metodo kontrau la metodo, ke oni ricevas normajn minuto-sekundajn signalojn per JJY (4MHz) sendepende ce ciu observejo, kaj konkludas, ke la nuna metodo per fadena telefonado estas almenau nuntempe pli praktika of la lasta.View full abstractDownload PDF (440K) -
Shosaku HOMMA1951 Volume 4 Issue 2 Pages 51-56
Published: December 30, 1951
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSApplying his general theory on the-initial value problem of the elasticity treated in spherical polar coordinates, the present author calculated the waves under a distribution of initial displacement.
Let the initial displacement be in two spheres r=a and r′=a being apart 2s with each other (cf. Fig. 2) in such a way that, its direction is parallel to the axis of x, but in opposite sense in the two spheres, and its magnitude is 1-(r/a) or 1-(r′/a). The displacement-components (u, v, w) of the generated wave at a large distance from the source referred to new coordinates (R, Θ, Φ) are given by where V and B are the velocities of P and S waves respectively and each term of the right hand sides should be understood to be null when |R-Vt-s·cosΘ/a|, etc, are larger than unity.
For some values of s/a and Θ, the quantities in braces are illustrated in Fig. 3 with the corresponding initial distributions of the displacement.
The above results may be applied to the waves when some forces having the tendency to produce a fault are suddenly impressed on a part of the earth's crust.View full abstractDownload PDF (426K) -
Naota KOBAYASHI1951 Volume 4 Issue 2 Pages 57-62
Published: December 30, 1951
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSIn the ordinary air damper used in a seismograph, the clearance between the moving piston and the outside cylinder is very narrow, causing no small difficulties for its adjustment. If the damper can be used with oil instead of air, a large damping can be obtained even with comparatively large clearance between the piston and the outside cylinder. In order to see whether or not, this attempt is practical, a series of experiment has been made.
To a pendulum which carries an oil filled piston damper, periodic forces were given and the response of the pendulum was measured.
It was found that the damper works quite satisfactorily, both in regard to the amplitude and phase relation.View full abstractDownload PDF (442K) -
Takuzo HIRONO, Soichi HISAMOTO1951 Volume 4 Issue 2 Pages 63-67
Published: December 30, 1951
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSUsually, the method of drawing front lines of traveling tsunami waves on a map uses the so-called Huygens' principle, that is, assuming the velocity of tsunami to be √gh, where g, the gravity acceleration, h, the sea depth, and drawing sufficiently many circles of radius √gh·t (t: a suitable short time interval) with their centers at as much points distributed adequately on a front line, we have the envelope of these circles as the next front line to be taken by the wave after t from the preceding.
But due to the inevitable discrepancy of an employed map from a spherical surface, the position of any front line thus drawn must diverge much from that drawn on a sphere, especially when the tranaoceanic wave is considered (See Table 1).
Nevertheless, the effect of this destortion of map can be eliminated comparatively easily if we adopt a stereographic map and draw individual circle with radius r=sin√gh·t/(sinφ+cos√gh·t) whose center deviates to the marginal direction of map from the original pasition on a front line by d={cosφ/(cos√gh·t+sinφ)}-{cosφ/(1+sinφ)}, where φ is the latitude and √gh·t is measured by radian, while the map is assumed to represent a sphere of radius 1. By this method the wave front of tsunami due to the Sanriku Earthquake of 1933 is drawn successfully (See Table 1). Differences between the observed and the calculated travel times remain within 2%.
Moreover, since a stereographic projection is a conformal representation of a spherical surface, an energy contained between two adjacent orthogonal trajectories is conserved and this enable us to calculate the energy distribution of tsunami wave throughout the coasts around the ocean.View full abstractDownload PDF (455K) -
Kenzo SASSA, Kumizi IIDA1951 Volume 4 Issue 2 Pages 68-70
Published: December 30, 1951
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSIn December 1950, we have mesured the gravity values at about 80 stations in the vicinity of Kyoto with North American gravimeter. The non-corrected results of the measurements are shown in table.View full abstractDownload PDF (251K) -
Tokio ICHINOHE1951 Volume 4 Issue 2 Pages 71-75
Published: December 30, 1951
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSAs results of arranging the gravity values inserted before by Sassa and Iida, a few facts were ascertained:-
1. Bouguer anomalies are shown in table and Fig. 1.
2. Secular variations at four stations are shown in Fig. 2.
3. Tidal variation has been observed (see Fig. 3), and the value of G≡1-(3/2)k+h was determined.View full abstractDownload PDF (372K) -
Ch. TSUBOI, Y. TOMODA1951 Volume 4 Issue 2 Pages 76
Published: December 30, 1951
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSDownload PDF (69K) -
F. KISHINOUE, R. IKEGAMI, H. YOSHIOKA1951 Volume 4 Issue 2 Pages 77
Published: December 30, 1951
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSDownload PDF (94K) -
J. SUZUKI, N. DEN1951 Volume 4 Issue 2 Pages 78
Published: December 30, 1951
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSDownload PDF (79K)
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