3i2 REPORT OF THE CALIFORNIA EARTHQUAKE COMMISSION. 
The pilot-boat Gracie S. was lying in 18 fathoms of water near the lightship off the 
San Francisco Bar. She was suddenly struck by a seaquake which caused her to quiver 
as if the chain were running out of the hawser pipe. When the pilot boarded the German 
Cosmos steamship Nyada, the captain reported that his vessel had been shaken as if 
she had struck on rocks. The pilot-boat Pathfinder was lying in the vicinity, in 20 
fathoms, and reported the same effect. 
The steam collier Wellington, inward bound, between Fort Point and Point Diablo, 
in 50 or 60 fathoms, reported that the vessel was struck as if she were upon rocks. (Per- 
sonal report of Captain Hayes, of the Board of Pilots.) 
The steamer Alliance, off Cape Mendocino, reported by Mr. H. H. Buhne, of Eureka: 
The captain said she was struck a hard blow, as if she had run on a rock at full speed; 
time, 5° 11". Mr. Buhne states that all ships in the harbor at Eureka felt the quake, 
but in South Bay it was heaviest. One vessel was hurled against the wharf time and 
again, throwing down piles of lumber and shingles. 
The schooner John A. Campbell felt the shock at sea, off Point Reyes. The following 
is a memorandum of the event by Capt. C. J. 8. Svenson: ‘Ship’s local apparent time 
April 18, 1906, 5" 15" a.m. Lat. 38° 00’ N. Long. 126° 06’ W.; 145 miles true west of 
Point Reyes. W eather fine; sky clear; wind fresh from north- northwest: sea moderate ; 
ship’s course southeast; speed 7 miles per hour. The shock felt as if the vessel struck 
lightly forward and then appeared to drag over soft ground, and when aft a slight tremor 
was felt; the whole lasting only a few seconds.” The depth of water in the vicinity of 
the ship’s position is 2,400 fathoms. 
The steamship National City was approximately in lat. 38° 24’ N. and long. 123° 57’ 
W,; 29 geographical miles distant from the nearest point on shore and about 31 miles 
from the fault-trace along the valley of the Gualala River. The vessel felt the shock 
t 5° 03" a. m., April 18, 1906, ship’s time. James Denny, the chief engineer, supplies 
the following comment: ‘The ship seemed to jump out of the water; the engines raced 
fearfully, as though the shaft or wheel had gone; then came a violent trembling fore 
and aft and sideways, like running at full speed against a wall of ice. The expression 
‘a wall of ice’ is derived from my experiences in the Arctic.’ In this vicinity the chart 
has several soundings, as follows: 911 fathoms over clay and mud at 11.5 miles on the 
line to Gualala Point; 1,586 fathoms over clay and ooze 8 miles north by compass; 
1,821 fathoms over clay and ooze 14 miles N. 54° W. by compass. 
The wharfinger at Santa Cruz reports that he heard a rumble before the shock, coming 
from the southeast, and saw the seismic wave traveling shoreward, causing a great rattling 
and crashing when it struck the town. Two distinct sets of vibration were felt, the latter 
being the harder. There was very little surf, the water looking like that in a tub when 
jarred. The wharf, extending southeast, s pocried to pitch lengthwise. A steamer between 
Santa Cruz and Monterey; alan one at Monterey wharf, ale the shock; it jarred them as 
if they had struck bottom. 
Shocks felt at sea subsequent to April 18, 1906. — The ship Alex Gibson, at 7" 05™ P.M. 
August 3, 1906, when in lat. 25° 35’ N., long. 110° 06’ W., experienced a tremendously 
heavy seaquake, lasting about 40 seconds and shaking the ship from stem to stern as 
if she were bumping over a ledge of rocks. It shook tools out of the racks in the ecar- 
penter shop; threw pots and pans down in the galley, cups and pitchers from hooks in 
the pantry, and all lamp glasses off the lamps. The crew came running aft not knowing 
what was the matter, and the captain thought the yards were coming down. The sea 
at the time was perfectly smooth, the wind light from the southwest, no land in sight, 
and all sail set in fine, clear weather. At 7" 10" p. m., ship’s time, another light shock 
was felt, of about 15 seconds duration; and from 8 to 12 midnight two more very light 
shocks were felt, but the time was not noted. The captain states that he had experienced 
