ISOSEISMALS: DISTRIBUTION OF APPARENT INTENSITY. 321 
EAST OF THE SIERRA NEVADA. 
Data CoLLEcTED BY Gro. D. LoupERBACK. 
General note. —In the towns along the east base of the Sierra Nevada and within 25 or 
30 miles of the base, the shock was distinctly felt, movable objects were seen to swing 
and heard to bump or rattle, and a very small number of persons were awakened. 
Farther east the most notable feature of the reports is that wherever the effects of the 
earthquake were made evident, the physical signs, such as the swinging of suspended 
objects, etc., were described almost to the exclusion of direct physiological effects. This 
is apparently at variance with the principles upon which the Rossi-Forel scale is founded, 
as the first 3 grades of intensity, beginning with the lowest, are based on feeling; the 
visible disturbance of objects not beginning until grade IV is reached. This may be 
due entirely or chiefly to the following conditions: Settlements are few and far between 
and many contain a very small number of inhabitants. When the earthquake occurred, 
the great majority were asleep, and the few who were up were moving about at active 
work and were in general not of a sensitive type. It is therefore probably impossible 
to get satisfactory and correct statistics indicating the distribution of the zones of inten- 
sity of the first 3 grades; and the sensible effects of the earthquake probably extended 
much farther east than reported. 
Perhaps the most important of the physical signs reported is the disturbance of smooth 
water surfaces. In five instances, at three different localities, ditch tenders or irrigators 
noticed an agitation of quiet water surfaces and that the water lightly splasht against 
the sides as if from low waves, or as in a vessel of water when it is slightly tilted. As 
the morning was clear and entirely without wind, it imprest them as peculiar, and the 
matter was reported when they went to breakfast. The suggestion of one that some- 
thing peculiar had happened, and of another that it was an earthquake, was each in its 
place the incitement of sallies of wit at the expense of the reporters. When news of 
the California earthquake reached these places several hours afterward, the time was 
found to agree as closely as determinable with the phenomena of the morning. In each 
of these cases, however, it was reported that no shock was felt. It is suggested that 
with moderately long waves such surfaces may prove very sensitive indicators of inten- 
sities down to the lowest degree on the scale. 
The farthest point east at which earthquake effects were reported was Winnemucea, 
about 340 miles from the fault. A careful search was made for persons who had felt or 
seen indications of the shock. Only one apparently authentic case was found, and that 
was of a nurse who had retired a little after 5 o’clock, after a night’s work at the County 
Hospital. She was lying quietly in bed and felt no disturbance whatever; but noticed 
a hanging lamp swing gently back and forth. Careful inquiry at newspaper offices, 
the telephone office, the post-office, and of the railroad agent, the weather bureau ob- 
server, and many individuals in different parts of the town, failed to discover another 
observation. ‘This is rather remarkable, because Winnemucca is a town of considerably 
over 1,000 inhabitants. It is believed that the one definite report obtained is correct; 
and, as corroborative testimony, may be added the reports from two other localities 
almost as far east as Winnemucca, in which similar phenomena were described (in one 
the disturbance of a water surface, in the other a swinging lamp), with the further simi- 
larity that no shock was felt. 
The elongation of the intensity zones in a northwest-southeast direction is marked. 
The strongest effects east of the Sierra Nevada were felt with practically the same in- 
tensity from at least Sierra Valley to Lone Pine (about 250 miles along the range), while 
50 miles east of the Sierra the intensity had materially lessened, and 100 miles east 
pe 
