Evening star., 1950-07-05
Greatest oceun Depth
Put at 81, ,440 Feet
Area Off Philippines Coast
Lowest Point on PIunet

HS0 MI huhpPttSS SVOSA
Lowest Point on PIunet
By Thomas R. Henry
The oceans greatest known depth is
34.440 feet.
This Is the Cape johnson Deep In the
Mindanao Trench OF the east coast Of
the Philippines. It Is apparently the
lowest point on the planet, exceeding
by more than q mile below sea level the
highest point, the summit Of Mount
Everest above sea level.
Such Is the conclusion reported to the
American Geophysical Union by DR.. II.
II. Hess Of Princeton University and M.
w. Buel. jr., Of the Navy photographic
Off1ce. DR.. Hess was commanding officer
Of the U. s. 8. Cape johnson when the
sounding was made.
There, Of course. may be still greater
depths not yet discovered.
Emden Sounding.
The accepted record up to now has
been somewhat greater, 35,400, based on
soundings made about % years ago by
the German cruiser Emden. This was In
the same general neighborhood, the So
called Emden Deep. about 40 miles south
Ol Tile cape johnson deep.
Examination Of the records, DR.. Hess
and Mr.. Buel say. throws great doubt on
the Emden sounding. It was made when
depth finding apparatus was quite primi-
tive and corrections for speed Of sound
in various temperatures and salinity of
water poorly systematized. The Cape
johnson measurements were made In
1945 when the human element was en-
tirely eliminated from depth soundings
and the latest tables of the British Ad-
miralty have been applied in making
corrections. The electronic soundings
showed a maximum depth of only 81 $3.50
feet.
Still difference Of nearly q mile
remains very great. It can be accounted
for, DR.. Hess and Mr.. Buel believe, by an
error difficult to detect-sound waves
echoed at an angle from the walls Of
the deep rather than directly from the
bottom. This possibility was eliminated
in the Cape johnson measurements.
Complicated Calculations.
1t is highly probable that the so-called
Mindanao Trench contains the deepest
water on earth. The Cape johnson with
DR.. Hess as commander surveyed the
whole area quite thoroughly, but the
34,440-foot depth was the greatest they
could obtain. Discovery of this lowest
point on earth was not announced at
the time since complicated calculations
were necessary to determine the validity
Of the Emden claims.
The whole Mindanao Trench, DR.. Hess
reports. has gently undulating bottom
surface. probably made up largely of soft
mud due to sinking of sediments from
the sea surface. Soft mud returns few
echoes, and these are difficult to inter-
pref. DR.. Hess and Mr.. Buel believe the
Emden commander was entirely honest
in making his claims.
The second deepest spot in the sea, the
report says, probably is the Ramapo
Deep. OFF the coast Of Japan. The depth
is 34,038 feet. The sounding was made
by the UjS.S Ramapo about Is years ago.
The measurements were made with stop
watch timing, subject to great errors,
and all have been subjected to intensive
analysis.
All that can be said for them with
any confidence, the report says, is that
they leave the Ramapo Deep, the second
greatest in the sea. It formerly was con-
sidered second only to the Emden Deep.
f&5I55 + &
Parallels Of latitude are from 20 to 80
per cent more elastic than meridians of
longitude.
In other words the earth is a lot more
"stretchable" east and west than north
and SOUTH
This has been reported to the Amer
ican Geophysical Union by DR.. Eiichi
Nishimura Of the Geophysical Institute
OF Kyoto University after probably the
most extensive studies yet made of "earth
tides More than 100000 pairs of star
observations were used in making the
calculations.
The phenomenon Of earth tides are
well known to geophysicists. The light
upper crust of the earth is under the
gravitational attraction of sun and moon
and hence displays constant tidal move.
ments. These are so small, however, that
they can be detected only with delicate
instruments and individuals never are
conscious of them.
Crust Fairly Elastic.
The extent of these tides depends on
the rigidity Of the crust, as well as the
temporary configuration of sun and
moon. DR.. Eiichi's observations show
that the crust is fairly elastic in an east
west direction. It is able to undergo
considerable distortions and snap back
into its old shape again, following either
tidal pulls or depressions due to heavy
weights.
At present no valid explanation can
be offered for the difference in the north
south direction, but the star observations
leave little doubt of the validity of the
phenomenon. They. however, are based
largely on Japanese stations.
DR.. Eiichi appeals for longer series
OF observations in other parts of the
world These need not necessarily be
tied in with the Japanese program which
was in process long before the war.
Questions and Answers