the assuzed atwosphere wodel.
The acoustic Tay emanating originally at 5o.5
degrees from Yeak burst point Lands wery close to French Frigate Shoals ani is
in fair agreement with the Te-degree incidence angle observed.
But application of modified Sachs scaling for shock stre=zth,
using
source estimated from Jobnston Island GZ blast data,
together with asbient pressure altitudes, gives shock speeds along
the rsy path.
Integration of shock speed along this path gives an arrival t
for comparison cry».
41 yield range in Table
6.6
Arrival times calculated for the
are 752 and &7 seconds.
These calculated arrival
times are all smaller than those observed, but the error is not nearly as great
as acoustic trawel time vould preduce.
Observed arrival would requ
rent source strength.
shock strengths along a path to FFS.
Two factors could cause smaller
First, a portion of the shock energy was
lost by rediation since it was observed to be of still glowing intensity as it
passed ower FFS.
Additionally, refractive convergence which ducted rays into
FFS, as shown in Fig. 6.6, is accompanied by a relatively silent region above
the turnover point, and a considerable upward diffraction of energy could bave
taken place.
In summary, calculated arrival tives
The Teak shock wave was photograpbed from Bawaii at irregular intervals up
to 2 mimtes after zero time 76
From these pictures approximate positions and
shock speeds have been calculated as shown,in Fig. 6.7. In addition, the field__
of shock speeds calculated by modified Sachs scaling for a
yield, together with ambient atmospheric pressures and temperatures, are saown.
ly”