lagoon floor.
The mean depth of the lagoon is 26.¢ fathoms, with depths between
e4 and 32 fathoms most common.
that the lagoon floor is
Bottom samples and underwater photographs show
chiefly covered with Foraminifera,
shells,
Halimeda
debris, coral and other miscellaneous fine debris.
In the Marshalls,
The slopes
the atolls rise out of water about 15,000 feet in depth.
of the atolls are steepest in the upper portions near the surface,
At Eniwetok the contour gradient reaches a rate of about 4,000 feet per mile.
Flgure 3 shows the ocean bottom contours in the vicinity of Eniwetok Atoll.
The original native population of Eniwetok Atoll was Micronesian and in 1930
consisted of 121 inhabitants who raised chiefly pigs, chickens and coconuts, and
caught the abundant fish available in the Eniwetok area,
In 1947 Eniwetok Atoll
was selected for an expansion of the permanent Pacific Proving Ground because of
its isolated position,
stable weather and the geography of 1lts land masses.
At
this time the Eniwetok people were moved to Ujelang, where nearly 200 natives
live today.
Since that time Eniwetok has been populated exclusively with Ameri-
eee
.
can personnel associated with atomic test operations.
The number of persons
present varies from tens of thousands during active operations to several hundreds during interim perlods.
The development of the atoll for test purposes
has consisted principally of the construction of permanent base camps on FRED
and ELMER Islets and of the utilization of the northern islets,
Runit to Bogallua,
extending from
for shot-site and technical instrumentation purposes.
3.
GENERAL WEATHER SETTING
Although detailed studies of the macroclimate of the Marshall Islands area
and of Eniwetok in particular are available in the literature (Appendix III), it
was thought desirable to include in this report a general description of the
weather setting of Eniwetok.
It is the purpose of this section to present a
general description that will be especially useful to those not familiar with
tropical meteorology.
Eniwetok is located on the south side of the Pacific high pressure belt, in
What is commonly called the north-east trade wind zone,
and to the north of the
ne
equatorial trough of low pressure,
Wind Structure.
eS
ee a
ne ae
Ee
Eniwetok is overlain with three nearly independent wind
ee
indication whatsoever of submerged terraces or cliffs on the deep portion of the