THE MORNING OREGONIAN, MONDAY, JUNE 25, 1906.
CALIFORNIA QUAKE DUE TO EARTH CRACKS
Breaking of Rock-Masses, Along Fault Lines, Made
Concussion That Shook Down San Francisco.
s
HEN a heavily laden wagon rolls
along a street. It sets up a minia
ture earthquake, that rattlea win
dows of near-by houses.
vneu a solid rock mans within, the
earth breaks under dislocations of ' the
earth's .crust, the snap and Jar make an
earthquake that shakes down cities.
in the case of the wagon the crust ot
the earth merely trembles within a small
area, became the Jar Is feeble. But In
the case or Uhe other the crust Is shaken
with a violence that wrecks buildings
and sends a o.irver throughout the world,
as recorded by scientific Instruments In
far-orr lands.
Breaking' of Rock Masses.
The earth Is wrinkling continuously Into
mountains and valleys. This movement
put an enormous strain on. the rock
masses beneath the surface. Sometimes
they bend and sO-etch wlthoux breaking,
but orten they split and tear apart. The
lip and Blind produce & concussion
called eartrtquake. Though the slip may
be only a few Inches, It is often disastrous
to the surrounding country and the undu
lations may extent hundreds tf miles.
This Is the kind of Jolt that shook San
Francisco. It Is the kind Chat' makes
the frequent shocks in Japan. To It are
traced the most destructive earthquakes
that have occurred not to volcanoes, tor
some of the severest quakes have taken
place distant from volcanea and the worst
of them have had no connection with
lava explosions. However, quakes are
commonest in mountain regions.
What Makes Earth-Wrinkles?
What causes the earth to wrinkle? This
question Is one of dispute among sclen
Ists. Some attribute It to shrinkage of
the earth's cooling mass. Just as a drying
apple shrinks and its skin wrinkles. The
crust of the earth Is but as a thin skin
only about 30 miles thick, while the globe
inside Is almost H000 miles through.
Another explanation Is that the heating
and expansion of rocks cause the
pressure that makes the fracture.
Still another Is that the erosion of the
earth's surface by water andjalr. and the
carrying away of enormous quantities of
finely powdered- rock-masses by rivers,
shift the weight of the crust on the
globe, removing a load from one region,
which therefore may tend to rise, ana,
taking it to anotbjer, which may be
caused to sink. This causes pressures at
weak spots and a collapse or yielding to
relieve the strain. According to this the
ory the breaks occur almost always near
the ocean, due to vastly Increased pres
sure of sand and silt on the ocean's floor.
The tlrst and the third explanations are
advanced by prominent geologists for the
Ban "rancisco, or rather the California
quake, for the disturbance was felt In
many large areas of the state, and that
ctty Buffered most on account of its vul
nerability. Earth-Cracks Are Weak Spots.
Where a break has once occurred there
after la a weak spot, and at that place
strains on the region round about are
likely to be relieved by new shlftlngs.
The breaks In the earth's strata are
called "faults." They are gaps, or lines
or cleavage In the layers of rock, that
make up the world's surface.
Are there faults In California? Yes,
many of them. California has had many
earthquakes In the century that white
men have studied the region. The moun
tain wrinkling of the Coast Kange Is
proved by geologists to be recent and still
In progress. The mountain uplift makes
many fractures, and most of them fol
low weak fault lines. The underground
Jars are transmitted to the eoil of the
adjacent country, becoming less violent.
the further away from the break.
Big Fault Near San Francisco.
One of these breaks Is south of Ban
Francisco, five miles west of Stanford
University, called the Portola fault. The
great shock ot April IS, 1906. was due to
a new fracture along this old fault, which
can be traced 40 mil, more or less, says
Dr. David Starr Jordan, by disturbances
In the surface soli. The known length
of this fault Is nearly zoo miles, reaching
more than 100 miles north of San Fran
cisco.
Other faults may have been Involved
also. The long parallel valleys of the
state are believed to have been caused In
part by old-time faults. "One great fault
that seems to have been involved In the
San Kranclsco earthquake," says Profes
sor J. C. Branner, head of the department
of geology, Stanford University, in the
Pacific Monthly for June "follows down
the entire length of the Santa Clara
A'alley. from about the headwaters of the
San Benito, south of Holllster, past San
Jose, through the Bay of San Francisco,
up the valley past Santa Rosa, Ukiah,
Wllletg and down the Kel Klver to JSu
reka. In Humboldt County, 350 miles.
Since the earthquake, this fault line has
not been examined thoroughly, but many
cracks have opened along Its axis, near
the south end of the Bay of San Kran
clsco, between Mllpltas and Alvtso. At
this place, not only were large cracks
opened In the soil, but for a couple of
days water ran out through the cracks,
bringing up sand and forming small cones
about them."
Crack 150 Miles Dong.
Another fault the one believed to have
been most involved In the break of April
18, and in the many successive shocks
since Is the one first mentioned. Along
the
California Coast, extending from
Garcia River, 100 miles north ot San
Francia?o, to Santa Cruz Mountains, 50
miles south ot that city, making a break
line over 150 ' miles In length. Where
this line dips into the ocean, muddy
water hag been observed by navigators.
Passing Ban Francisco, this line is under
the ocean, and running south, it enters
the shore again at Mussel Rock, seven
and one-half miles south of the Cliff
House. It appears that the land on the
oceanslde of the -break shifted northward,
or that on the inlandside, where San
Francisco stands, the land moved south
ward, or that both these movements took
place on the two sides of the break.
The conclusion to be drawn from geo
logical and seismical observations Is that
earthquakes In California have been of
frequent occurrence and that they will
continue. The many faults visible in the
surface of the earth are evidences of the
many Jars to which California has been
subjected.
"The fact, however," says Professor
Branner, "that there are so many and
such recent faults In this region, leads us
to expect that there can be no very de
structive shocks, simply because great
strains cannot accumulate In rocks so
much broken. There will be small shocks
but it is Improbable that there will ever
be anv more violent than that of April
18. 1906."
Coast Range a New Ridge.
The process of mountain formation is
going on continuously. New crests are
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rising out of the sea and other portions
of the earth are sinking. The Coast
Range, in California, Oregon and Wash
ington, Is one of the young mountain
chains that have been "squeezed" up out
of the sea by pressure on the earth's
crust, resulting In "folding" or "rump
ling" of that crust Into mountain ridges.
The earth's crust is composed of layers
or strata of rock, that were deposited,
mostly by the sea more than one
half the surface of the earth being
of rocks that were laid down by the sea,
as is pointed out by Ralph 8. Tarr, pro
fessor of geology, Cornell University.
These layers are displaced from their
even, level form, and often tilted and
folded by the "wrinkling" already de
scribed, and while some of them, under
tne enormous pressures to which they are
subjected, yield without fracture, often
times they break with a concussion that
makes an earthquake.
Mountains are of slow, not sudden
growth. This is the rule, though there
are exceptions. While they are irrowini.
plants and animals and men dwell upon
them, scarcely aware of their rise, 'xue
Japanese Islands and the East Indies are
examples of mountains still in this mov
lng process, and In those regions earth
quakes are common. The breaks that oc
cur in the strata open fissures in uie
earth s crust, which release the molten
masses beneath, resulting in volcanoes.
Volcanoes Duo to Faults.
Such lava spouts are common in moun
ituns, ior tne reason that mountain
growth produces fault breaks or Assures.
These fissures, if near the ocean, often nd-
mlt sea water Into the hot Interior of the
earth. Then follows a battle between the
expansive energy of the pent-up steam
and the retentive resistance of the sur
rounding strata, ending in an explosion
like those of Vesuvius and Pelee. This is
the most violent kind of volcanic erup
tion. The most notable eruption on record was
that of Krakatoa, In 1883. in the Straits
of Sunda, between the Islands of Java
and Sumatia, when halt the Island was
Diown into the air. A prodigious mass
of ash and dust was hurled upward ap
parently reaching elevations as hlirh
15 miles above the sea. where th flnei-
portions floated about in the UDDer air
currents, passing entirely around the
earth and causing brilliant sunsets in
both Europe and America. To a distance
of 150 miles from the eruption the day
was darkened. Some of the ash fall
ing back on the island buried the pur-
face to such a depth that a new vegeta
tion has been obliged to develop. Vast
quantities of ash fell also on the sea
and floated about In such masses that
for weeks navigation near the volmnn
was difficult. The eruption also nro-
duced a great earthquake wave, that
rushed on the neighboring coast, flooding
it to a neignt iw reet above the ordinary
sea level, causing an appalling loss of
life. The wave extended as fax as the
coasts of America. Africa and Australia,
having passed over a distance of more
than 5000 miles.
Volcanoes Not Quake-Makers.
Mighty as was this eruption, earth-
shaking was not felt even close to the
Island, though thunderlngs were heard
across two oceans. In 1S88, when Ban
daisan. a mountain in Central Japan,
suddenly blew oft its head and. shoulders,
the earth tremors hardly extended 60
miles. Drawing conclusions from these
facts, John Milne, a celebrated English
scientist, says:
"As earthquake producers volcanoes do
not add one per cent to the seismic his
tory of our globe. From time to time
they produce crops of tiny tremors, and
that is all. To a certain extent both
may be regarded as having a common
parentage, but beyond the fact that an
earthquake occasionally shakes a Volcano
into activity, their direct relationship is
slight."
Thus it is not to bewupposed that vol
canoes and earthquakes stand in the re
lation to each other, of cause and effect,
but that they represent different expres
sions of- the same subterranean force.
This force Is usually believed to be contraction-
of the earth, whose pressure
either causes the rising of liquid rock
near enough the surface to be expelled
by steam through the fissures made by
the breaking of the strata, or melts the
Tocks In the roots of mountains, through
the liquefying force of the pressure, and
the molten lava coming In contact with
water. Is forced to the surface and blown
out by steam.
One Cause Produces Both.
Therefore we see that one agency pro
duces volcanic eruptions heat while an
other produces earthquakes faults and
that while the origin of the two may be
the Bam there la m liltly, connection 1
4 " T -v , -1.- '
between the activity of a volcano, say
of Vesuvius, and a quake of the earth
In another part of the world, say In
California, though a quake might stir a
volcano to action. What causes the rise
of mountains and the sinking of other
areas and what produces the lava and the
steam? These are unanswerable ques
tions. But we are digressing from the real
subject of earthquakes.
The Pacific Coast of America is the
latest addition to the continent, and
the Coast Range, whose growth Is be
lieved to be the cause of the faulting
about San Francisco, is the youngest
of mountain ridges. Time was when
that portion of America west of the
Allegheny Mountains was beneath the
ocean. At that time the Appalachians
or the Atlantic coast were as great
a chain, perhaps, as the Rockies, to
day. This was "long before the flood,"
as pointed out by H. S. Lyman, in his
History of Oregon and long before the
ages ot ice and indeed far back toward
the Archaean times.
Grow tli of American Continent.
Slowly this part of the present con
tinent rose from the ocean, forming
mountain chains, between .which ex
tended gulfs from the sea or Inland
seas. The Rockies lifted themselves
up, then the Sierra Nevadas and the
Cascades. The Willamette Vallev fn
Oregon was a sound, whose waters sur
rounded the hills that are now seen to
rise like islands from the Plain. The
basin of the Columbia River was an in
land sea, whose remnant Is Great Salt
Lake and the Blue Mountains were an
island, overlooking an expanse 'which
has now been raised to a continental
plateau. The pressure of the earth's
shrinkage, throwing up the Cascade
Mountains higher and higher, opened
fissures through the fault breaks, up
wnicn wenea molten 4ava, seeking re
lief from the inside . pressure, and
building up the cones of Mount Hood,
Mount Jefferson and Three Sisters in
Oregon; Mount Adams, Mount Rainier,
Mount St. Helens and Mount Baker.
In Washington, and Mount Shasta and
other numerous peaks in California.
But there was an earlier time, when
even the Appalachian range was an
ocean bed; the strata of that ancient
range, though worn down by the de
nuding agencies of air and water,
show that they were deposited by the
ocean and were uplifted by the buck
ling of the earth's crust.
Strata Deposited by the Sea.
For a long time before the Appala
chian and the Rockies and the Cas
cades and the Coast Ranges began to
rise there waa a preliminary settling
of the sea bottom, during which thick
deposits of sediment were accumu
lated on the ocean floor. These moun
tains therefore were made out of thick
beds of sediment, which were depos
ited mostly if not entirely near the
shore lines during a period of long
continued subsidence. Such was the
condition preliminary to the rise of
the Appalachians, these mountains be
ing formed out of sediments which in
some places -became 30.00D or 40,000
feet thick. As these beds were folded
up by the earth's pressure, there was
a crushing of the materials, faulting
and outpourings of molten masses.
In California the Sierra Nevada, and In
Oregon and Washington the Cascades
once formed the western boundary of the
North American Continent. The Pacific
Ocean washed against the foot of that
range. Just as it now washes against the
foot of the Coast Range, Where Cali
fornia now is, marine sediments accumu
lated to a thickness of 30,000 feet. Just
before the arrival of existing forms of
life on the world, these sediments, yield
ing to lateral pressure, were crushed up
ward. The Coast Range slowly rose from
the ocean and California came into ex
istence. Such is the explanation made by
the English scientist, John Milne, who
says further:
California a New Land.
"Geologically, It ie an extremely new
country; Us faulted rocks show that it
has experienced many severe shakings,
whilst its history tells, us that it is in a
state of seismic unrest, particularly in its
central region. Like Japan, the Alps and
the Himalayas, the Coast Range is still
growing, and as it increases, fracturing
of 'rocky strata must take place. As an
evidence of Its growth, it may be men
tioned that the precise levels made from
San Francisco toward Los Angeles a few
years ago differ from eight inches to a
foot with those made last season. Not
only is there a bending upward, but from
San Francisco northward the strike of
the Range changes, and horizontal de
formation may also play Its? part In the
production of seismic stress.
"If the water of the Pacific could be re
moved, we should see a coast rang not
merely 1200 feet In height, but a steeply
sloping ridge of 13,000 feet. The basal
frontier of slopes, with the steepness
these figures Indicate, are recognized dls-
1. Breaks in street pavement and ruined water mains on Valencia street.
The bulldinc on the left hu sunk to the second- Door.
2. Cracks and displacement on a fault line near Stanford University.
3. The Coast Ranee, at the toot of wtilch San Francisco Is situated, consists
of closely compressed and contracted strata, which have broken under excessive
strain with a shock that caused the recent great earthquake. The places of the
breaks are known to geologists aa fault and are cracks In the earth's crust. The
strata represent eediments which collected on the sea floor until they were 30,000
feet, more or less. In thickness. Eventually they yielded to horizontal pressure,
supposedly from weight of the sea floor or from contraction of the earth, and were
buckled up In their present position to make one of the laat additions to the
American Continent, the Coast Range. This range, like most mountain rldces,
represents a line of weakness In the earth's crust, and the recent great earth
quake indicates that the process of mountain formation on the western side of
North America has not ended. It waa still buckling up, when it suddenly
yielded, April 18, 1806, and the crash which followed save rise to the earth
quake. 4. Cracked pavement at Eighteenth and Howard streets. ' (The foregoing pic
tures are from the Pacific Monthly.)
The large map, accompanying the above pictures. Is marked by black lines
along the "faults" where the earthquake started from fracture of internal rock
masses.
At least three main cracks or "faults" In the earth's crust are believed- to
have been Involved In the California earthquake, being places where the break
ing of subterranean rock masses, under the "wrinkling" of the earth and the
buckling up of the Coast Range, made Jars which were transmitted to San Fran
cisco and other places.
One of these, believed to be the largest and the cause of previous quakes
In San Francisco, Is that which has been traced along the Coast from Garcia
River, 100 miles north of San Francisco, past that city on the ocean side to the
Santa Crux Mountains, 60 miles south ot the Bay City.
Another is that running through the Santa Crus Mountains, between San
Jose, inland, and Santa Cruz, on the ocean.
The third runs the entire length ot Santa Clam. Valley, from San Benito
River, south of Holllngsworth. past San Francisco, through the Bay of San
Francisco, northward past Santa Rosa. Ukiah Wlllets and down Bel River to
Eureka, on the ocean, a distance of 350 miles.
trlets of seismic activity. Soundings also I
indicate that along this suboceanic fron
tier submerged valleys of considerable
depth are to be found. Such a valley ex
ists near Monterey, off the mouth of the
Salinas River, extending westward toward
the bed of the Pacific.
"From Salinas on April 27 we hear that
chocks were felt every day since the
shock of April 18. The Salinas River had
Bunk 10 or 13 feet along its course for
miles. Nearly all the bribes have been
condemned ana will have to be rebuilt.
From this and other records, it may be
Inferred that the Salinas Vallev
and invisible, was as much a center of
disturbance as was San Francisco."
Many Quakes In California.
Many quakes have been felt in Cali
fornia in the century that white men
have been closely familiar with.
This is not the case with the Ore
gon and Washington portions of the Pa
cific Coast, which have the Cascade and
Coast ranges to match the Sierra Nevada
and Coast ranges of California. In Ore
gon and Washington it cannot be said
that a slight tremor has never been felt
in the earth's crust, but there have been
no earthquakes here in the 75 years that
white men have been living in these
states.
The first earthquake recorded in Califor
nia was In October 11, 1800, followed In
1803 by a second shock, and again In 1806
by a third one. The years IRIS, 1830 and
1857 each were marked by severe seismic
disturbances. In 186S there waa a very
heavy shock around San Francisco Bay.
Others followed in 1S71. 1898, 1889, and
finally the disastrous one of last April.
Evidences of the rise and depression of
regions of the earth's surface are many.
The Middle Western portion of the United
States has been sinking for many years.
On the New England shore there are
many places where forest trees and peat
bogs are under the ocean tide. The coast
of Maine carries evidence of land sub
mergence; so do the Hudson River, the
St. Lawrence, Delaware and Chesapeake
Bays and San Francisco harbor. The coast
of New Jersey Is known to be sinking at
the average rate of two feet a century.
Two years ago Chicago was startled with
the announcement that the site of the city
is subsiding.
Signs of Increasing Elevation.
, In many parts of the world there are
abundant evidences also of growing eleva
tions along shore lines. The great earth
quake in Japan in 1891 caused the ground
to rise on one side of a fault which was
traceable over a distance of many miles.
The shore of Peru was raised three or
four feet by an earthquake in 1832. and a
part of the shore of Chile was raised four
or five feet in 1835. Along the western
coast of South America "there is evidence
of a much greater elevation in recent
times. An example of this movement Is
cited by Professor Tarr, ir his work on
geology, as follows:
"The evidence of the movement of the
land that has been most frequently de
scribed. Is that of the Temple of Jupiter
Serapis, near Naples, In Italy. This was
built near sea level, and three of its col
umns are now standing, while the floor of
the temple is beneath the water. At a
height of 12 feet above their base these
columns begin to show the borings of a
shell, the lithodomus, which bores In the
stones on the shores of the Mediterranean.
The borings on these columns continue
through a distance of nine feet. They
could have been made only while the col
umns were standing In water, and the rea
son for their absence In the lower 12 feet
is that the lower 12 feet were cased In
mud. So built on dry land, these columns
sank 21 feet 'or more and then were raised
again to nearly this height. Even while
the Romans used the temple the land waa
sinking and a new floor had to be laid
above the water level."
To return again to-the California earth
quake. Dr. Jordan on California Quake.
As has been said, San Francisco stands
on the inland side of the great fault that
runs along the coast. On the ocean side
of that city the fault dips under the sea.
On the authority of Dr. Jordan, we learn
that the Sierra Morena, which forms the
backbone of the peninsula of San Fran
cisco, has suffered a displacement. The
fault on the ocean side of the range
has slipped northward, he says, three to
six feet, with change of level on either
side. It is from readjustments along this
line that San Francisco earthquakes
usually originate, and the frequent lesser
shock since April 18 come from further
settlings along the line of this fault.
Evidence of displacement is seen In the
shearing oft of water mains. Unfortunate
ly for the city, the mains were laid out
so as to cross the fault near the northern
end of the structural valley at an angle of
about 45 degrees. When the earthquake
came nothing could save them. No mat
ter what their construction might have
been, the very great shifting which oc
curred would have produced the same re
sult. They were cut as though by a huge
knife.
The maximum slide was approximately
six feet. All pipes and pipe lines were
shaved off. Where fences crossed the fault
the sections on either Bide are displaced
many feet. The whole of the western
fragment seems to have been moved for
ward toward the north-northwest.
Ruins Xear the Fault.
Everything on or near the line of this
fault suffered severely. Stanford Univer
sity was near It and Is almost a ruin. Sa
linus City, nearly in its path, is laid
waste. The large sugar plant below Sa
linas, built by Mr. Spreckles, has buckled
up, and the huge steel beams shortened up
a foot or two. San Francisco lay some
what to the north and east of the fault
and suffered very severely In places. Here,
In some localities, the Jelly-like shaking
was most marked, and wherever In the
city was soft soil, or fllled-in land, there
great damage resulted.
On the other hand, the experience has
demonstrated that even very large build
ings may be built upon such soil, If the
foundations are constructed with the na
ture of the soil and the liability to earth
quakes ever In mind. For example, the
ferry building Is built on piles sunk In the
mud of the bay, yet the floor of the build
ing Is perfectly level, and the building
Itself in all essentials is undamaged. But
the foundations of the ferry building were
put in to stay. There are 73 groups of 60
piles 80 feet long, driven down into the
hard blue clay. On top of these groups of
piles concrete arches were built, and on
these arches rests the Ferry building, a
structure of steel and cement. When the
earthquake came luls building, practically
a solid mass from foundation to top, vi
brated as a unit, and, except for the split
ting off of some of the stone casing, Is
undamaged.
Many changes and land shifts have been
noted in addition to those observed along
the fault, but the general opinion of those
who have studied the problem seems to
be that all such lesser movements, as for
Instance, the sliding of secondary faults
wnlch branch from the San Bruno, are re
sultants and not causes. In places such
secondary faults, which meet the main at
an acute angle, give the appearance of
having been thrust wedgelike north into
the land above. Here the knowledge gained
by Proiessor Branner In years past will be
of the greatest value, as the measure
ments and surveys now being carried on
by him will tend to clear up many of these
now obscure points, particularly when
taken In conjunction with the work of the
Coast Survey in re-establishing the exact
location of what are called points.
Displacement at Big Break.
Professor Branner describes the fault
as follows, in the Pacific Monthly:
The northern end of this line of
fracture has not yet been gone over
by the writer, but from Mussel Rock
toward the southeast It has been ex
amined in detail to near Lorn a Prieta,
in the Santa Cruz Mountains, Every
where along the southern part of this
lino the rocks have been broken,
shifted and squeezed past each other.
Being an ancient fracture, the rocks
upon and everywhere near the break
are so ground up that it is seldom
that large blocks are to be seen near
the fault. In most places the soli is
deep and yielding, so that any move
ment along the fault is partly taken
up by the drag or yielding of the soil
and loose materials that conceal the
fault. These details are important,
because they suggest that the total
displacement along a fault plane Is
not likely to be clearly and fully
shown by the displacement in the soil
or elsewhere on the surface of the
ground, and they also account for the
fact that the displacement visible at
(Concluded on Page 9.)