wave forms, indicating that the shock had picked up
at several Underwater Sound Transmission Experimental Facilities (USTEF) stations in the Pacific and
at similar research stations in the Atlantic. The
water. For these two shots, the gage group was lo~
cated near the edge of the water
The force plate and density gage seemed to be
studies were designed to lead to a better understanding
guitable for field use, but study was needed on their
of the underwater sound propagation and to determine
responseto dust.
the accuracy of device yield figures that might be ex-
“Instrumentation for Projects 1.2a, 1.3, and 1.7”
(WT-907), Sandia Corporation; R. H. Thompson,
Shots 2, 4, 5, and 6 were monitored by detecting
stations located on the California coast and at Bermuda. No clear-cut signals were recorded which
could be attributed to sources at either Bikini or Eniwetok. It was concluded that the positions of the shots,
inside the lagoon and on the atoll rim, precluded the
coupling of energy into the SOFAR channel in the frequency channel to which the instruments were sensi-
tracted from the measurements.
project Officer.
The primary objective of this project was to make
support measurements of pressures, shock winds,
and ground accelerations from large scale detonations
for Projects 1.2a, 1.2, and 1.7. A secondary objective was to field-test several new gages.
‘he primary measurements were made with
Wiancko and Sandia pressure transducers, differential-pressure yg-tubes, and accelerometers. Other
tive.
Project 1.6 ‘Water Wave Measurements” (WT-916),
Scripps Institution of Oceanography; R. R. Revelle
inetrumentation used included drag q-tubes, forec-
and John D. Isaacs, Project Officers.
plate stagnation-pressure gages, density gages, temperature gages, and displacement gages.
Of the records taken on 112 data channels, 99 gave
complete infurmation: 6 gave information up to arrival of the shock wave; and seven gave no information. Preliminary evaluation of new instrumentation
indicated that: (1) the density gage needed better
The objective was to study water surface waves
generated within the lagoon by a large-yield surface
detonation. The measurements of wave height were
obtained from underwater gages designed to record
the hydrostatic pressure vibrations produced by the
passing wave. In addition, surveys of inundation
levels on land areas were made.
In contrast to the Ivy-Mike results, Castle data indicated that the recorded waves did emanate from the
central region of the detonation. The time of arrival
of the first crest of the direct water wave showed a
waterprooiing, (2) the force plate operated satisfactorily, (3) the temperature gage was still too delicate
for field use, (4) the gage q-tube was easy to caliorate but needed waterproofing to protect the cantilever f-omn vusting and to protect the E-coil, and (5)
propagation velocity fitting the relation V = (gh)!/?,
the differential oressure gage was easy to calibrate
but needed waterproofing.
where bh is an average depth of 170 feet assumed for
the Bikini lagoon. Refraction and reflection against
the reef or shoreline can significantly reduce or amplify the destructive capabilities of water waves at
termination. Where focusing effects and the reflectionrefraction potential of the adjacent lagoon topography
Project 1.4 “Underwater Pressure Measurements”
(WT-908),Office of Naval Research; W. J. Thaler,
Project Officer.
This project was designed to measure the under~
water pressure-time field produced by large-yleld
surface bursts. Pressure-time measurements end
pall-crusher-gage measurements were obtained for
Shots 2, 4, 5, and 6; ball-crusher-gage measure~
ments were obtained for Shot 1. The gages were located as close aa 6,000 feet from ground zero.
Some difficulty with instrumentation was experienced during the operational phase; as a result, a
lesser amount of reliable data were vbtained than
originally anticipated. The major result of the re-
was a minimum, the heaviest inundation and potential
damage occurred with the first crest. These results
were obtained uncer particular conditions of geometry,
in a region of relatively shallow depth; such damage
criteria are applicable to conditions that depart only
slightly from those under which the data were obtained.
Project 1.7 “Ground-Motion Studies on Operations
Ivy and Castle” (WT-9002), Sandia Corporation; W. R.
Perrett, Project Officer.
corded data indicated that the maximum, or peak,
This project was designed to obtain measurements
of three components of ground acceleration on Shots 3
underwater pressures are of the same magnitude as
the air~blast peak overpressures at the same range.
It was concluded, therefore, that a nuclear weapon
detonated on the surface of a relatively shallow water
layer, under conditions as experienced on the Castle
shot, produces underwater pressures which are probably of small military significance.
Project 1.5 “Acoustic Pressure Signals in Water
(SOFAR)” (WT-909), Office cf Naval Research; J. W.
Smith, Project Officer.
The objectives were to make special observations
and Echo. These measurements were to be closer in
to ground zero than those obtained on Ivy~Mike and
hence augment and extend those measu -ements previously obtained. Unfortunately, the yield of Shot 3
was only about a tenth of that expected and Shot Echo
was cancelled.
As a result of the low actual yield of Shot 3, set
ranges for the gages were too high, recording a verylow signal amplitude. With such a low signal-to-noise
ratio, the identification of phase arrival, frequencies,
107