Evening star., 1932-01-13
CRACKS" IN EARTH,
TO Be EXPLORED
Dutch Scientist in Capital
Arranging for Expedition
to West Indies.

Discovery of great cracks" In the
earth, thousands of miles long, was an
nounced before the Washington Acad-
emy of Sciences last night by Prof. F.
A. vening Meinesz of the Geodetic
Commission of the Netherlands.
The Dutch explorer, who in the past
few years has travelled more than $4,000
miles in submarines to locate these
cracks" by gravity measurements un-
der sea, now Is in Washington arranging
for a joint expedition of the United
States Navy and Princeton University
to the West Indies where, he believes,
one of the great earth deformations ex-
tends. Use of Navy submarine has
been secured and the expedition will
leave some time this Winter.
1t is along these gravity cracks, DR..
Meinesz explained, that earthquakes
occur and mountains are upfolded.
They are the signs OF powerful forces
operating deep in the earth. DR..
Meinesz Is the inventor Of gravity
measuring apparatus which measures
the pull of this force on the ocean bot
tom, but which must be operated In
submarine below the disturbance zone
of the waves.
The Netherlands scientist is working
on the theory of isostacy, largely de-
veloped by scientists Of the Coast and
Geodetic Survey here, which holds that
the crust of the earth, about 20 miles
thick, floats on plastic surface and is
maintained in equilibrium. So long as
this condition is maintained the weight
of large areas of the surface should pe
the same, mountains being made OF
light material and valleys of heavy ma
terial. When they get out OF equlll-
brium earth disturbances, such as
earthquakes, result until the balance Is
restored.
Now, he explained, the pull Of gravity
should be the same all over the earth II
the balance were perfect. When IL
varies, either to increase or decrease
the equilibrium is upset. These Varla-
tions can be determined only oy ex-
tremely accurate measurements. Ontu
DR.. Meinesz perfected his apparatus,
nobody had succeeded in measuring the
gravity pull undersea.
theoretically, DR.. Meinesz explained,
the lowest readings should be onta1neo
over the great ocean depths, such as
the one off the coast of Porto Rico or
the we'll known Philippine deep.
Two years ago, in Navy submarine
and in cooperation with scientists OF
the Carnegie Institution Of Washington,
he made extensive measurements IN the
West Indies. Since then, in a Dutch
he has carried on more ex-
tensive work In the East Indies.
Low-Gravity Belt.
The curious feature of his results, he
said is that the greatest abnormalities
do not occur over the greatest sea
depths, although these show negative
readings, but along their borders. In
the East Indies he found narrow line
about 5000 miles long where all his
gave negative readings,
positive gravity abnormalities. All along
this low-gravity belt is an earthquake
center. The crack extends eastward and
finally disappears in the Pacific.
DR.. Meinesz found another crack ex-
tending near the Pacific Islands OF
Guam and Yap and the evidence Is
that still another passes north Of Haiti
and Porto Rico. Whether there Is any
connection between these low gravity
belts is unknown. To determine the
direction and extent of the Porto Rican
crack will be the chief object of this
Winters expedition. There is some evil
dence that it may cross Mexico into
the Pacific and extend along the deep
ocean west of California. Low gravity
readings have been obtained along the
Pacific Coast and may be associated
with worldwide phenomenon.
These cracks" DR.. Meinesz main
tained, have been split open by powerful
forces deep In the earth. Earthquakes
and mountain building, taking place
along the same lines, are minor symp-
toms Of the same forces at work.
Crust Buckles Inward.
The cracks mean that the earth's
crust Is buckling inward. This may re-
suit from the cooling and shrinking of
the interior, or be caused by the grad
ual drifting Of continents across the
surface of the globe, resulting in
changes of pressure at different points.
The great deeps of the ocean, he holds,
are sections of these cracks that have
not been covered with surface material.
The buckling itself takes place many
miles below the surface.
DR.. MeineSz' discovery may go far to
explain the prevalence of earthquakes
around the Pacific area and enable
scientists to predict where they are to
be looked for in the future They also
throw some light on the changing
countour of the earth.
The possible relation between the
East Indian creak and the great piled
up masses Of the Alps and Hima1ayas to
the north was indicated. But, DR.. |
Aketnesz said, the gravity measurements