~~
Stations 170.01, 170.02, and 170.03 were placed at that depth; those at Stations 170.04 and
170.05 on Rujoru were placed at a depth of about 17 {t in agreement with gauge depths adopted
for similar stations on Operation Ivy.
STA, 170.02
STA 170.03 —
STA 170.015
GROUND ZERO-7
i»
~
3
:
/ |
ree nannapfe
BIGIREN
ano nnrtane
anannannt
vee
5
Muerte
o” ENRIKKU
£
ENINMAN
Le"
Fig. 2.1—Site plan showing location of ground-motion stations fort
(Bikini Atoll).
2.3
aaa
| overation Castle
INSTRUMENTATION
End instruments and mounts were essentially the same as those used for Project 6.5 of
Operation Ivy. The cases in which the accelerometers were mounted were redesigned to ensure better waterproofing. Instrumentation for recording gauge output consisted of carrier
amplifiers and magnetic tape recorders backed up by photographic recorders and is described
in the instrumentation report for the Sandia Laboratory projects.!
,
Set ranges for the accelerometers were assigned on the basis of data from Operation Ivy.
Initial set ranges were increased shortly before calibration as a result of an increased estimate of yield. Fina] set ranges for vertical and radial components were 33 g for Station 170.01,
24 g for Station 170.03, and 9 g for Station 170.02. ‘Tangential component ranges were lower.
Calibration procedures and installation were essentially the same as those used during
Operation Ivy. The spin-table used for accelerometer calibration was revised to ensure
smoother operation.!
2.4
DATA ANALYSIS
0. $e
Eight of the nine acceleration channels fo —
gvoperated satisfactorily. The ninth
channel, responding to vertical acceleration at Station 170.01, became inoperative probably because of damage to the cables by water waves from one of the earlier shots. It was not feasible
to repair or replace the gauge since it was already in the ground. Consequently no vertical
acceleration data were recorded for “as close-in station.
The yield of' _
sshot\was about one-eighth the earlier estimate of 1 Mt and
about one-twelfth the estimated yield used for final calibration. The result of low-yield and
consequent high set_ranges was very low recorded signal amplitudes. A secondary result
of the low yield of
jshothwas cancellation of th
__ Shot and consequent
limitation of the ground-motion data to those from the earlier shot.
32