Evening star., 1923-05-13

~ CHEMISTS, with the co-opera-
tion Of United States officials.
are going to set off something
- like twenty tons Of surplus war
explosives about a half mile under
! make an earthquake, so that they
can study the effects.
This Is only one Of many ways in
which the vast store OF surplus ex-
plosives Is being used for the bene-
At of the public in agricultural and
reclamation work, and In scientific
experimentation.
After the war the tremendous
, amount of surplus explosives which
Uncle Sam found on his hands be-
came q cause OF worry. so much so
that shiploads were taken out to sea
and thrown overheard.
DR.. Charles e. Munroe. chief of the
explosives section of the National
Research Council. and explosives ex-
pert for the bureau of mines. has
been chief adviser Of the government
as to how the surplus explosives can
be used to the best advantage. 1t
occurred to him that it would be
very good idea to use as large a
quantity as could be allocated for
such an experiment to produce an
artificial earthquake, so that scien-
lists might get exact Information that
heretofore has been lacking.
Tho idea was discussed by DR..
Henry S. Washington, a geologist in
tho geographical laboratory of the
Carnegie Institution, after confer
ences with DR.. L. H. Adams. physicist
in the geophysical laboratory, before
a recent private gathering Of govern
ment scientists at the American Geo
physical Union, here in Washington.
It promptly won the enthusiastic sup
port Of the leading scientists DIR.
Arthur L. Day, director of the geo
physical laboratory; Rev. Francis A.
Tondorf. chief OF the Georgetown
| University chronological observatory,
and Col C. G. Storm, representing the
ordnance bureau OF the War Depart
ment, are among those cooperating
in tho experiment.
The only notable previous artificial
explosion which scientists had an op-
portunity to study as a simulated
earthquake was when Gen. H. L. Abb
bott on October 10. 1886. blew up
Flood Rock, He'll Gate. by an arti-
ficial explosion OF 2&o.ss9 pounds of
rock-a-rock and 48,637 pounds of
dynamite, No. /. Gen. Abbott took
advantage OF that opportunity to
measure the rate of transmission Of
the tremors started by the explosion.
He got q record OF four miles a sec
ond as the highest rate of speed, but
he had only very crude instruments.
The proposed experiment with sur
plus war explosives In an abandoned
mine differs very materially from this
He'll Gate study two score years ago,
because that was near the surface.
while the plan now is to go as far
underground as possible and to get
moro accurate results with mechani-
cally recording instruments, specially
built.
While the study that the scientists
will make Is extremely technical and
tho problems involved are intricate.
yet tho public can get some idea OF
Of what is sought.
Ono question IL with regard to what
is known AZ "the sone Of silence"
Whom an explosion occurs. as for ex-
ample during . battle. there will be
some places where It will be heard
ana then tho "sone Of silence will
intervene. and again there will be an
area where IL Is audible. Tho sci
entists do not know much about that
"xone Of silence" and want an oppor-
tunity to study It.
The great majority OF earth
quakes-at least s6 per cent-are
caused by . slipping at crack in the
earth. This crack IL known geo.
logically as q fault" ana an ilius-
tration IL tho ono that cuts through
San Francisco, known as the san
Andreas fault" Some times the sides
Of such a crack slip UP or down, or
again they may slip horizontally, as
occurred at San Francisco. Some
times there are both motions.
That explosion takes place over q
long slip. sometimes a mile, or maybe
twenty miles. So there is no one def
mite point Of the earthquake.
In studying an earthquake one Of
the most important questions which
the scientists concern themselves