436 REPORT OF THE CALIFORNIA EARTHQUAKE COMMISSION. 
In general, the direction of throw of objects was north or south. rom several tanks 
the water slopt north and south. Nearly all the chimneys reported were thrown 
either north or south. Several frame houses were thrown south. One of these, 0.5 
mile south of the line of the fault, was thrown 4 feet and another on the line was violently 
thrown 6 feet. 
Several people report that rumblings preceded the shock, coming apparently from 
the south or southwest. Others saw a wave-like motion set up in the surface of the 
ground approaching from the south or southwest. 
THE EFFECT OF THE EARTHQUAKE IN SAN FRANCISCO. 
At San Francisco and nearby points the earthquake lasted for about 42 seconds. 
It was in general north and south. A second shock followed the first at 9" 23" a. M., 
and lasted for 5 seconds, with the same direction as the first. Until about 12" 15" p. m., 
light shocks continued to be felt about every 30 minutes; and inside of the 24 hours 
immediately following the initial shock, 12 minor shocks were felt. The first indication 
of the approach of the earthquake was a slight rumbling sound, coming apparently 
from the direction of the ocean. The sound was heard very distinctly in the lower part 
of the city, but the residents on the hills do not appear to have heard it. (San Francisco 
Times, Oct. 21.) The shock commenced in the form of slow, horizontal movements. 
The oscillations continued from 10 to 15 seconds, growing more rapid and more violent 
for 6 or 7 seconds, then partially ceasing for 3 or 4 seconds, then increasing in force and 
rapidity for 4 or 5 seconds, then suddenly ceasing. (Alta California, Oct. 22, 1868.) 
There were no abnormal barometrical changes at the time of the earthquake. No 
chronometer in Mr. Tennent’s office was disturbed or showed any change of rate. The 
pendulum clock in his office was not stopt. A transit instrument erected on Russian 
Hill, belonging to him, was not disturbed in the slightest degree. Two magnets, one in 
his office and one in charge of a friend, showed no loss of magnetic power. One was 
loaded to its full extent, and the slightest loss of power would have permitted the weight 
to fall. (Bulletin, Oct. 22, 1868.) 
The portion of the city which suffered most was that part of the business district, 
embracing about 200 acres, built on ‘made ground”; that is, the ground made by 
filling in the cove of Yerba Buena. (See plates 145 and 146.) The bottom of this cove 
was a soft mud varying from 10 to 80 feet in depth, and the material used to fill it was 
largely “dump” refuse, much of which is organic and hence perishable. Many of the 
buildings of that period were built flat on this filled mud, without piling, and before 
the land had had time to become firm. On this made land there was a very evident 
belt of maximum damage several hundred feet wide and running about northwest and 
southeast, commencing near the custom-house and ending at the Folsom Street wharf. 
One account of this belt goes so far as to trace 8 or 10 distinct lines of maximum dis- 
turbance, practically every building on these lines being more or less damaged, while 
none outside of these lines was seriously injured. 
In many places the made land settled. At the junction of Market and Front Streets, 
the ground sank for a foot or two, and there was evidence that the tide had risen in the 
adjoining lot at the same time, for a pond of water collected and remained until low tide. 
On Pine Street, near Battery, the cobbles on the south side of the street sank away from 
the curbstones to the depth of 1 foot in some places; and the asphalt sidewalk on the 
north side was twisted and torn out of all shape, and its connection with the curb-stone 
severed. (Alta California, Oct. 22, 1868.) 

1 Thos. Tennent, agent U.S. Coast Survey, in Alta California, on Oct. 22, 1868, reports it as lasting 
46 seconds and as being from southeast to northwest (nearly) in direction. 
