ISOSEISMALS: DISTRIBUTION OF APPARENT INTENSITY. 305 
The mill stands on flat, alluvial ground 100 feet north of Alameda Creek. Along 
the banks of the latter a large number of cracks extend, roughly parallel with the stream. 
Considerable masses next to the stream-bed slumped toward the same, leaving gaping 
cracks 1 to 2 feet wide, and carrying with them small outlying buildings, notably the 
fire-engine house, which moved bodily, concrete foundation and all, 2 feet south toward 
the creek. A small railroad trestle southwest of the mill moved 4 inches south on both 
of its abutments, probably owing to slumping of loose ground on the north side of the 
creek. A 2-inch water-pipe, laid under the ground some 60 feet north of the creck and 
almost parallel with the same, shows indications of having been submitted first to ten- 
sion, causing rupture at one of the joints, then to sudden compression, causing it to be 
jammed together with violence. 
Cracks in the ground may be found as far as 250 feet from the creek. They were 
nearly all closed at the time of the visit (May 7), but were easily traced by the streaks 
of bluish-gray sand which has issued from them, together with considerable quantities 
of water. According to the Chinese cook of the superintendent, the cracks nearest to 
his dwelling opened and closed several times in succession during the quake; and large 
volumes of mud-laden water gushed from them, splashing up some 10 feet in the air at 
each closing. A large crack of this kind opened under the northwest corner of the dwell- 
ing, and the superintendent estimates that fully 500 gallons of water gushed from it, 
the flow continuing with decreasing volume for about an hour. The fence in front of 
the house shows that the ground there has been raised into a low hump. The sewer 
pipe leading west to the creek was detached from the house by a space of 22 inches. A 
chimney near the northeast corner of the house was thrown to the east with sufficient 
violence to throw the farthest bricks 35 feet east of the house. The top of the chimney 
was only 20 feet above the ground originally. 
In the roadway south of the mill, water oozed out in a number of places, without the 
production of visible cracks. The water pipes and hydrants in this vicinity were crusht 
in several places. 
At the Alvarado Water Works the brick buildings suffered considerable damage, the 
walls cracking in several places. Nothing could be learned regarding the behavior of 
the wells of this plant. The frame dwelling of the superintendent was damaged by the 
collapse of its underpinning. A similar fate befell the Alvarado Hotel. Both houses 
were being put in place at the date of the visit. At the school-house the water-tank fell 
owing to the collapse of its supports. 
Nearly all brick chimneys in the village fell, the directions varying. A few cracks 
opened across the streets, but these had been filled on the date of the visit. The con- 
sensus of opinion was that the shock had a north-south direction. 
Lick Observatory, Mount Hamilton. — From the reports of astronomers C. D. Perrine, 
R. G. Aitken, H. K. Palmer, K. Burns, A. M. Hobe, and G. A. Vogt the following obser- 
vations as to the character and intensity of the shock have been obtained. The prin- 
cipal disturbance was preceded by a tremulous motion variously estimated at from 
11 to 15 or 20 seconds. There seemed to be 2 maxima, the first being the stronger (?), 
according to H. K. P. There was a first secondary maximum about 5 seconds after the 
beginning, a maximum 11 seconds after the beginning, and another secondary maximum 
about 15 or 20 seconds after the beginning, according to K. B. 
A tremulous motion was felt after the principal disturbance. 
“Heavy vibrations were still felt 60 seconds after the first count. Motion was felt for 
nearly 2 minutes after the first count.” C.D.P. “The duration of this tremulous motion 
was about 30 seconds. Vibrations stopt in the house at the end of that time.’ K. B. 
“Duration between 30 and 35 seconds.” A. M. H. 
No vertical motion was perceived, nor was any recorded on the Ewing seismograph. 
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