§8 _ REPORT OF THE CALIFORNIA EARTHQUAKE COMMISSION. 
The instruments used were: 
(1) Stiattesi horizontal pendulum, east component; mechanical registration on smoked 
paper. 
Ty, 17.6 seconds; V, 25; J, 1,900 meters; M, 208 kg.; L, 1.75 meters. 
(2) Vicentini mieroseismograph, east component; mechanical registration on smoked 
paper. 
First 
PRELIMI- 
NARY 
TREMORS. 
SECOND 
PRELIMI- 
NARY 
TREMORS. 
REGULAR 
WAVES. 
PRINCIPAL 
PART. 

m. é. 
min. 
Ty, 3.4 seconds; V, 155; J, 450 meters; M, 312 kg.; L, 2.88 meters. 
PERIOD. 
EartH’s 
AMPLI- 
TUDE, 
mm. 
(1) East component | 24 54.6 to 11.0 

54.7 to 11.0 
mis: 
54 39 
42 11 
(2) East component | 24 

Average .. .| 24 
Intervals smd Le 








Duration, 5.5 hours. The time of the regular waves is taken a little later than the 
time marked on the seismogram; it is evident that what is here taken for the beginning 
of the principal part is that of the regular waves on the Krakau, the Pavia, and the 
Vienna seismograms; it is accordingly so considered in the determination of velocity of 
propagation. 
PAVIA, ITALY. 
R. Osservatorio Geofisico. Dr. P. Gamba, director. 
Lat. 45° 11’ N.; long. 9° 10’ E.; altitude, 81.7 meters; distance, 86.20° or 9,583 km.; 
chord, 8,707 km.; direction, N. 32° E. 
Foundation, Quarternary alluvium, about 200 meters thick. 
Seismograms, sheet No. 7. 
The instrument used was an Agamennone vertical pendulum, two horizontal compo- 
nents; mechanical registration with ink on paper. 
(1) Northeast component: 7'5, 6 seconds; V, 20; J, 180 meters; e, 1.14; r, 0.88 mm.; 
M, 200 kg.; L, 8.96 meters. 
(2) Southeast component: Ty, 6 seconds; V, 20; J, 180 meters; ¢, 1.52; r, 1.05 mm.; 
M, 200 kg.; L, 8.96 meters. 


SECOND 
PRELIMI- 
NARY 
TREMORS. 
First 
PRELIMI- 
NARY 
TREMORS. 
REGULAR PRINCIPAL 
WAVES. Part. 



™ ™ 8. ™m, &. 
. 8. . 
(1) Northeast component} 25 06] 35 06] 54 00 
(2) Southeast component] 24 46 
Average... « 4) 247567) 35 3.06 
Interval : 12 28) 22s 
m. 8&8. m. &. 
59 20t008 40 
02 30t008 30 
00 55? 
48 27? 



54 00 
41 32 






Duration, 2+ hours. The second group begins more sharply in the northeast than in 
the northwest component, 7.e., at right angles to the direction of propagation. The long 
waves are also better marked on this component and the principal part begins earlier and 
lasts longer, tho it has a slightly greater maximum on the other component. This is 
probably not a question of period, as both components have the same; but the less well- 
defined record of the southeast component is probably in part due to the greater friction ; 
its value of r is more than twice that of the other component. 
