Los Angeles herald., 1906-07-22
VISIBLE EVIDENCES OF THE EARTHQUAKE
Herman Fault" San Francisco Which
Caused Great Disaster
Front

I by heavy fault which formed Spring
! valley and the system of ponds and
lakes that furnish The San Francisco
water supply. Along the valley run
three well-defned faults. the San An
dreas and San Bruno, which pass to
sea at different angles, and a third
which diverges in the direction Of Santa
Rosa, and accounts for the enormous
destruction in that city.
The origin of Spring valley thus un-
lderstood, a little additional data enables
us to guess what happened on the
morning of April 1S. Geologists divide
earthquakes into two classes, volcanic
and tectonlc. Tho former occur at COM
paratively shallow depths. diffuse their
vibra tions from a definite center, have
a short radius Of influence and are not
followed by after quakes. They may
I'm fact, be closely initiated by the ex-
plosion of large quantities of dynamite
at the bottom Of deep mines. Tectonic
qua kes, on the other hand, occur at
greater depths and are caused by the
breaking of strata along a line. Their
waves are sent from this line, whatever
it's length, and they are always followed
by after quakes. To this class belongs
the great Japanese earthquake before
mentioned, which killed 1000 people,
stroyed 100000 houses. II was caused
by movement along a fissure which APP
peared on the surface as fault sew
enty miles in length, and after an eX-
haustive study, Professor John Milne
concludes that they are more frequent
i'm districts that exhibit evidences of
elevation or subsidence, such as our
own Pacific coast.
This understood let the reader place
hn 1Y,,c nf ha nd
left representing the Pacific ocean and
strip of coast line; the right, the re-
mainder of California. For years. per-
haps centuries, the rock strata beneath
have been exposed to increasing strain
by enormous and unknown forces 1t
may be caused by the shrinkage of the
earth's envelope on a cooling center
once molten as some say; by vast
masses of sediment that have been car
ried out by the coast rivers, millions on
millions of tons, and have been depos-
tied on the ocean floor till the weight
breaks down the strata, as maintained
by others. Be this as 1t may the
limit of elasticity had been reached
at Sis on the morning of April Is.
Here at that hour, at the head of
Spring valley, the air is warm and
meadowlarks are singing, Mr.. Fay,
foreman of the Sneith ranch is bring
ing up the cows that will not supply
San Francisco's breakfast, Unknown
to himself he is riding along the fault,
but beyond the eerie stillness-dubbed
earthquake weather" by Californlans
there is nothing to indicate that,
miles below, vast subterranean forces
are poised on hair trigger.
Now shoot the left hand forward and
the right back. With a roar, a rumble,
a crash, grinding of rocks. the cry of a
world in pain, the strata break along
the old fault. Zip! it slips eight feet,
laterally, along it's % miles of land line
and nobody knows how many more of
ocean bed The Pacific slides north
eight feet; California comes eight feet
south. When the evidence is all in,
Professor Lawson of the geologists of
the state commission will doubtless tell
us which; but their verdict makes no
difference upon the personal problem
of Mr.. Fay on the Sneith ranch
To understand what happened to him,
just upend book on the table and
snatch the table cloth eight feet. The
legs were snapped from beneath the
horse, and when, bruised and shaken,
Mr.. Fay rose, he was thrown again to
the ground. Lying there, he saw that
his cows were all down, some rolling,
others whirling spasmodically in their
attempts to get up. UP at the mouse,
Mrs. Fay was thrown from the stove,
where she was cooking breakfast. out
through the open doorway Fancy!
what if that fault had gone through
San Francisco? Though she is In ashes,
the unfortunate city may be thankful
that it had passed six miles outside her
borders. Had it cloven her center. the
foundations borders.
Not far from the Sneith ranch came
on the first break in the Spring Valley
Water company's twenty-inch main,
the pipe that supplied most of San
Francisco's water. Broken here and
pushed apart till it's sides overlap 1t
was fiattened farther on, telescoped or
wrenched apart according to the angle
at which it crossed the fault. Imagine
the power required to telescope one
length of buried iron pipe upon an
other of the same gauge! Yet this oc-
Cured at a hundred points. For a mile
it was pulled apart at every joint; be-
ginning with half-inch apertures. the
breaks grew wider and wider between
every length, until the maximum Of
y-eight inches was attained. Cross
ing the San AndreaS dam, mammoth
structure the fault moved one end