The sun. [volume] (New York [N.Y.]) 1833-1916, 1906-04-20
n EARTHQUAKE.

Inc STUDY OF earthquakes ID u CoHhPoio-
lively new science, but fortunately the
seismologists Of to-day will be ablet to learn
many definite and valuable facts concern
ing the San Francisco shocks that could
not have been ascertained thirty years ago.
Only half a century has elapsed since Mr..
Percy of France and Mr.. Robert Mallet OF
England began to collect and collate the
records Of earthquakes in various parts OF
the world, but the long lists thus obtained
after infinite pains were little more than
catalogues Of the woes endured by the
inhabitants OF a few earthquake countries,
and they led to no solid results hat could
help to make such phenomena, their origin
and modes Of action, better known to US,
1t Is only since 1887 that seismology has
taken its place as a science to be studied
by long and careful observations X any
other exact science. Its birthplace was
Japan, which is not surprising when we
consider the circumstances In many
countries earthquakes occur at such long
intervals and are as q rule. 80 local In
effect that no continuous observation 10
possible. In other large regions earth
quake shocks when they come are 30 VIC
lently disastrous as to render n work
except flight to a place of safety impossible.
In Japan, however, the situation is differ
emit. Japan has it's terrible earthquakes
marking their paths by ruin and DEATH
but they are few compared with the num-
Der Of harmless earthquakes. There are
many hundreds of slight shocks every year
doing little or no damage, and here the
student has ample and safe opportunity to
collect facts.
This opportunity was seen by Prof. John
Milne, who occupied the chair OF geology
In the University Of Toxic. He formed a
society Of natives and Europeans which in
a few years collected q mass OF facts with
regard to earthquakes that surpassed In
value all that the previous four centuries
| had placed at the service Of science.
Among the results was the perfecting OF
instruments for recording earth motion,
and there is no doubt that s~eismographs
all over the world have recorded the San
Francisco shocks. Science may now deter
mine, il the required data are obtained;
the %epicentrum, or, in other words, the
particular surface beneath which the sub
t~evanean jar that caused the earthquake
occurs. 1t may also determine approd-
mately the depth beneath the surface at
which the trouble begins. Thus the place
Of origin or the epicentral tract OF the
Charleston earthquake was In the region
Just west and southwest Of the city, about
twelve miles beneath the surface.
1t is probable that the place Of origin OF
our last disastrous earthquake will be ascer-
tanned. Unless the shocks were followed
by heavy earthquake sea waves along the
coast it is perhaps more probable that the
epicentrum was under the land surface
than under the sea floor.
According to the Washington report,
the earth waves produced by the shocks
reached the seismographs there in less
than four and one-half minutes after the
original occurrence at San Francisco. II
this report 10 accurate, the rate OF trans
mission was more than eleven miles In a
second, a remarkably rapid rate OF move
ment, though earthquake waves travel
with widely varying velocity. In the
Charleston earthquake the rate was about
1900 feet, or a little more than three miles,
in q second.
We know nothing as yet to indicate that
the disturbances radiating from this earth
quake began to compare with those from
the Charleston shocks. Seismographs were
few in number and very imperfect in 1888,
or we should have heard OF that earthquake
from stations all over the world. But the
shock was slightly felt in this city and was
appreciable to our senses to the west OF the
Mississippi River and in the southern part
of Ontario. The effects OF the San Fran
cisco earthquake of sufficient intensity to
be recognized without the aid Of seismo-
graphs appear to ave been confined to
the region extending a few hundred miles
around the city.
One or two scientific men seem to take
a gloomy view Of the future safety OF San
Francisco and the Pacific Coast. Such ex-
pressions are both untimely and unwar-
ranted. Biologists agree that there is
nothing cataclysmal about the upheaval or
subsidencs of parts Of the earth's rock
crust. The movements are very slow,
occurring through thousands Of years,
and when as a result OF these movements
the rocks in a small area are displaced by
faulting land this seems to be the cause
of the present earthquake) experience is
against the idea that a similar calamity OF
equal intensity will again affect the same
area for a very long period OF time, and
perhaps for many ages. Caracas, to be
sure, has suffered severely since the earth
quake that overthrow her in 1912, but that
CITY stands in an area Of unusually rapid
mountain formation, and her case is
exceptional.
We cannot discover or reckon with the
future phenomena of the forces Of nature;
but moral fibre and stamina have been
given to mar to help him to rise superior to
such great Affections as that from which
our grand city on the Pacific is now suffer-
ing. without delay San Francisco will
begin to repair her material losses and her
stout hearted people will bend every energy
to reestablish all their enterprises as soon
as possible.