The New York herald., 1922-12-03
Earthquakes and Their Causes
Science Has Learned Good Deal About Them but
Has Not Discovered Means Of Forecasting Them

by sudden faulting, others by slow and
gentle movements. Biologists have in
ferred that the North American Great
Lakes. whose beds extend many feet
below sea level. were formed by slow,
warping displacements.
A clearer case Is the New Madrid
displacement This case involved q
series Of earthquakes covering the period
from December, 1911. far into 1872.
The region involved extended from
southeastern Missouri into Arkansas
The testimony Of witnesses shows that
tAs tops Of black walnut and other bot
tom land trees were covered by the
water which gathered within the de-
pressions. The lakes and ponds within
the sunien area wore greatly enlarged
and new lakes were created. To THE
day the area is known rs the sunk re-
gion. The quakes and tremors were
due to sudden earth movements.
Many displacements have occurred IN
localities where the rock layer IL COW
ered by tho sea. Such movements have
created the tremendous waves popularity
known as tidal waves. The Lisbon
earthquake of 1855 was an Instance.
The shattering OF the walls Of buildings
drove tho frightened people to the quay
and the seashore, where they might
escape falling walls. Then huge wave
rolled in from the sea and enyulfed
them At tho docks the Tagua River
rose forty feeeabovc its ordinary level.
Tidal waves are common enough along
the Pacific coast OF South America. In
t0n In
tho region around africa. then q lively
port of 10000 population In Per't and
now q small and almost shipless port.
Tho United States warship wateree.
then at anchor In the port. was carried
high ON the crest of the wave and
dropped gently IN q stream bed several
miles inshore.
. The recent shocks along the Chilean
coast have again brought UP the Quss-
tion OF extraterrestrlal causes o&
earthquakes and also a discussion Of
the possibility Of forecasting them. At
least one thsory. that of the electrical
origin Of quakes. may be dismissed as
ingenious and interesting but without
evidence to substantiate 1t.
A small class OF theorists who at
tribute many Of the things which vex
humanity to planetary influences assert
that planetary positions account for tho
occurrence Of earthquakes. Certain 1t
is that the conjunction Of several plan
cts exert theoretical strain. but their
combined attraction Is not sufficient to
produce a measurable tide In the ocean:
it Is negligible compared with that OF
An continuation ~ SavAral
planets produces enough gravimetric
force to create an ocean tide the tide Is
too inconslderable to be measured.
When we consider the possible force
Of the moon the question is more prom
ising. The attractive force OF the moon
Is sufficient to mass volume OF water
several thousand miles in width, ex-
tending theoretically from pole to pole.
The tide in question has midooean
depth OF about three feet. There are
two of these tides. and in turning upon
its axis tho earth slips under each one
in q period a little moro than twelve
hours II, express in figures the weight
Of the water thrown upon . given area
would have but little meaning. Tho
Observations OF Alexis Percy show
pretty positively that earthquakes are
rather more frequent when the moon 10
on the meridian than when 1t Is on the
horizon. therefore the influence OF the
tide. Percy has shown also that earth
quakes are rather more frequent whom
the moon In nearest the earth and when
the earth is nearest the sun.
This does not mean that the moons
attraction and the massing Of the tides
cause earthquakes: It does indicate,
however. that the attraction Of the sun
and the moon may have a measurable
effect In fixing the time at which they
occur. That Is, when an earth strain
not quite sufifcient to break the rock
layer occurs the position OF the sun and
the moon may advance or 1t may rctard
the time OF occurrence.
Perhaps the time will come when
earthquakes may be forecast as weather
forecasts are made; but the time is not
now. The sonic depth finder recently
put into use as very practical appa-
,ratus for measuring sea depths will GER
tainly give new and better methods for
finding the focal point Of earthquakes
which originating below the sea bottom
cause the destructive tidal waves, but II
Will not help in the matter OF forecast
ing earthquakes.
The researches OF Milne and Maliet
AFFORD little or no help in this respect.
The testimony of Dr.. Omori OF the
Japan Earthquake Commission IL worth
noting: "Future studies connected with
the movements OF the earth's crust may
advance our knowledge In forecastint
great earthquakes. which often are pre-
ceded by what may be called FORE
shocks" And this is the most hopeful
opinion which has been expressed up
70 the present time.