It is necessary to take into ac count the topographic and regional characteristics of high winds, when we are estimating the design wind speeds for buildings and structures. Furthermore, it is more desirable to use the estimated value of the maximum peak gust for these purpose. This report first describes a method to obtain the expected extreme value of mean wind speed per 10 minutes taking into consideration the topographic factors at a given places. For this mean wind-speed dada obtained in more than twenty years at 124 weather stations in Japan were used. An electronic computor was utilized for the calculations. Next, is described the results of the analysis of gust factors recorded by aerovanes at all the weather stations in Japan. The regional characteristics and the differences between the gust factors caused by a typhoon and by an extra-tropical cyclone were also decribed. According to this study, the expected values of the maximum peak gust which is available for design wind speeds can be obtained for any places in Japan.
It is studied by means of sca l e analysis what sets of equations are to be applied to quasi-geostrophic disturbances in low latitudes. The vorticity equation becomes the barotropic equation in a first-order approximation, and it is used to prognose a stream-function field and not a geopotential field. The divergence equation is primarily modified to the so-called balance equation for long waves and altered to the expression of the geostrophic relation for ultra-long waves. These formulae each turn out to be the diagnostic equation used to seek a geopotential field from a given stream-function field in a contrary relation to middle latitudes. It is moreover concluded for ultra-long waves that the magnitude of zonal wind takes the order of 10 m⋅sec-1, that of meridional wind must be, at most, of the order of 1 m⋅sec-1 and the continuity equation is used to determine the magnitude of meridional wind. The thermal equation loses the prognostic property for thermal change and represents the diagnostic equation used to estimate the magnitude of vertical motion even if including the time-change term in it The vertical mortion is primarily contributed by a non-adiabatic heating effect only. So we need generally to give the two kinds of data of a stream-function field and a non-adiabatic heating effect as initial data to solve the obtained set of equations.
In order to examine the MSK seismic intensity scale as to its suitability to a country like Japan,106 stations under JMA (Japan Meteorological Agency) observed perceptible earthquakes by the MSK and JMA scales in the same time during four years from 1967 to 1970. Questionaire cards were made for the report of the observation of phenomenal items to determine the MSK intensity whose final determination was done by the authors. The reported shocks were divided into two categories, small shock and large one. Then they were investigated statistically in comparison with the JMA one. It was made clear that the JMA scale is adequate to the lower grades of intensity (1-3 in JMA), but it is rather rough to apply to the higher grades, whereas MSK scale is suitable to the higher grades and not adequate to the lower ones. The formula to estimate the MSK intensity corresponding to the JMA one of lower grade as high as 3 is obtained as M=1.5J+1.5, where M is the MSK intensity and J the JMA one. In the case of a large earthquake the relation between the two scales is approximately given by M=1.5J+0.75 for MSK 5-8. Each scale has its merits and defects and it is advisable to employ both of them by JMA using the JMA scale for urgent report and the MSK one for minute investigation in field work in the case of a large earthquake.
A liquid-filled resilient cylinder is placed in a borehole and intimately coupled to the surrounding rock. When the strain in the rock changes, liquid is displaced, contracting or extending a thin-walled bellows, into a gas-filled volume, the pressure of which is substantially independent of the rock strain changes. The motion of this bellows is transmitted to a differential transformer as well as to a bimorph-type Piezo-electric crystal. The frequency response of the bimorph sensor is flat from 1 cps down to about a twenty minute period and at lower frequencies is strain rate sensitive. The output from the differential transformer is of course strain sensitive at all frequencies. The operational sensitivities are 2 × 10-9/mm for the differential transformer and 3 × 10-10/mm for the bimorph on the recorder (Figs.1 and 2). Three strainmeters have been installed in the Matsushiro region in central Honshu, Japan, which has a very high seismicity. Two of the instruments are only 300 meters apart, and the third one is 15 kilometers away from the pair. A number of examples of strain steps have been recorded by the 100 m quartz-bar extensometer in the Matsushiro Seismological Observatory. It appears that a number of the steps on the extensometer are probably spurious, for the new strainmeter showed no such steps or much smaller steps (Table 3). One of the fundamental features of th e strainmeter is its invulnerability to high accelerations which are likely to be encountered during local earthquakes. To test the performance, the strainmeter together with its surrounding rock was subjected to accelerations as high as a few hundred gals, using explosives. No spurious behaviour was detected.
Ozone number densities in the altitude range 22-62 km were determined by a rocket measurement of the absorption of solar ultraviolet radiation in three bands within the range 250-370 nm. This sonde was flown on January 23,1970 from Uchinoura. Because of parachute failure, profiles of air temperature and wind could not be obtained, though it had been planned to measure them simultaneously. The present result genera lly shows a good agreement with other experimental data. Our profile is also found to support the theoretical profiles for the moist atmosphere model rather than for the oxygen atmosphere model above 30 km. But our data were not in good agreement with balloonborne chemical ozonesonde data obtained the day before for altitudes between 30 and 22 km.
Earthquakes occurring in and near Japan have been located routinely in the Japan Meteorological Agency (JMA) using the travel time tables prepared by WADATI et al. (1933) and SAGISAKA et al. (1935). These tables were prapered on the basis of distributions of velocities for P and S waves which were determined by H. HONDA (1931), K. SAGISAKA et al. (1935) and others. The velocity distributions used in t he calculation of the tables were elaborately determined for accuracy of observations of P and S arrival times at that time, and until a recent the tables had been usedin JMA without inconvenience in the determination of parameters such as the origin and origin time of local earthquakes in and near Japan. By K. AKI (1965) were found a discrepancy as large as a few seconds between arrival times of P for focal depth 0 km in the table and the explosion seismic data in epicentral distances ranging from about 20 km to 200 km (Fig.2). The discrepancy will have in fluence on the determination of parameter of local events. And, as a matter of fact, the origin time of earthquakes determined by JMA is 1 to 2 seconds earlier than those calculated by K. AKI (1965), and the Research Group for Travel Time Curve in the Earthquake Research Institute of the University of Tokyo confirmed the phenomenon. Trouble sometimes occurs in the calculation of earthquake parameters by use of a computer in JMA, because the travel times given in the tables are liimted to 0-1500 km in distance and 0-500 km in depth. In order to determine earthquake parameters whose magnitude is down to 3, JMA is developing a new seismological network, and many data for local events are obtained by the new developing network. Under the circumstances, the above-mentioned discrepancy of the standard travel times and the explosion seismic data is problematic in determining the parameters of events by use of data obtained from stations close to the epicenter. In order to settle the above-mentioned problems, travel times of P and S waves for local earthquakes occurring in and near Japan were calculated by taking the explosion seismic data into consideration.