OBSERVATORIES AND THE DATA OBTAINED. 77 
Duration, 3.1 hours. The period during the strong motion is closely that of the pendu- 
lum and in the absence of strong damping and exact knowledge of the damping ratio, 
the movement of the earth can not be estimated. The letters on the seismogram refer 
to the following times: a, 13° 24™ 24°; b, 34™ 13°; c, 42™ 26°; d, 47™ 56%: e, 53™ 515: 
ee ong 25" As. hf, lbs 01" 46%: 440" 11". 7) 16" 33" 08". 
KOBE, JAPAN. 
Meteorological Observatory. C. Nakagawa, director. 
Lat. 34° 41’ N.; long. 136° 10’ E.; altitude, 53.3 meters; distance, 77.54° or 8,619 
km.; chord, 7,976 km.; direction, N. 55° W. 
Foundation, Paleozoic rocks. 
Seismograms, sheet No. 5. 
The instrument used was an Omori horizontal pendulum, north component ; mechanical 
- registration on smoked paper. Ty, 35 seconds; V, 10; J, 3,000 meters; M, 5kg.; L, 
75 cm. 









(a) First Preutmi-|(b) SECOND Pretimi- | REGULAR 
NARY TREMORS. NARY TREMORS. WAVES. Max AMPLITUDE, | PERIOD. 
Mm. 8. Men 8: 5s Fs mm. sec. 
North component . 24 23 34 19 52 56 15 23 
Interval . Ube Meats Pal fap 







Duration, 3 hours. Altho the long waves appear quite definitely to begin at (c), the 
time seems somewhat late. There are two well-marked but separated waves in this part 
of the motion with a period of 31 seconds and a very large amplitude, possibly in part 
due to harmony of periods. The amplitude of the earth during the principal part can not 
be determined as the motion lasted only a short time and the damping is small. 
The letters on the seismogram refer to the following times: a, 135 24™ 238; b, 34™ 198; 
egg ed a soe 6. 5055" * fF 14 06™ 06's 9, 12" 32%.’ hy’ 22208 4. HTB 
7, 16°26" 13% 
KEW, ENGLAND. 
National Physical Laboratory. Dr. Charles Chree, in charge of seismograph. 
Lat. 51° 28’ N.; long. 0° 19’ W.; altitude,6 meters; distance, 77.63° or 8,630 km. ; 
chord, 7,986 km.; direction, N. 32° HK. 
Foundation, deep alluvial gravel; Mesozoic limestone 1,150 feet below the surface. 
Seismograms, sheet No. 1. 
The instrument used was a Milne horizontal pendulum, east component; photographic 
registration. 7,18 to19 seconds; V,6.1; J, 520 meters; ¢, 1.114; 7,0.0mm.; angular 
displacement, 1 mm. = 0.55”; M, 255 gm.; L, 15.6 cm. 
First PRELIMINARY SECOND PRELIMINARY REGULAR Max 
TREMORS, TREMORS. Waves. AMPLITUDE 
min, min, min. min. mm. 
East component . . 25.7 34.0 50.0 57.0 to 02.0 17+ 
Interval "scan 13.2 21.5 37.5 




Duration, 3.8 hours. The time of the first preliminary tremors has not been used in 
the determination of velocity of propagation; it is fully a minute later than at all other 
stations which do not differ considerably from Kew in distance from the focus; and the 
beginning of the movement on the seismogram is too indefinite to permit a satisfactory 
determination of its time. 
