308 
PACIFIC SCIENCE, VoL XIX, July 1965 
names able, bravo, DELTA, and K-K; Figure 2, 
traverse GASHOUSE; and Figure 3, the shorter 
traverses in the caldera area to probe for shal- 
low structures. 
In the longer traverses of ABLE, bravo, 
DELTA, and K-K the explosives were set off 
under water at sea. The technique of fixed 
recording stations with moving shot points 
was used. For the K-K series the shooting 
crew operated from outboard motorboats be- 
cause the largest charge-size amounted to 40 
lb of tnt. For the able, bravo, and delta 
series, the 85-ft R/V "Neptune I” of the Uni- 
versity of Hawaii was used as a shooting plat- 
form because the charge-size used was large — 
either 200 lb or 500 lb of nitromon. For the 
K-K series the charges were detonated at the 
bottom of the bay, which on the average was 
40 ft deep. For the able, bravo, and DELTA 
series all shots were fired 75 ft below the water 
surface. 
In the GASHOUSE series (Fig. 2) a fixed shot 
in Kaneohe Bay on the north side of Oahu was 
used while the recording trucks moved in a 
southeast direction away from the shot point. 
In a number of short traverses to probe for 
the shallow structures of the caldera area, 
charges ranging from Vi -lb blocks of TNT to 
35 lb of nitromon were detonated in a drainage 
canal cutting across Kawainui Swamp which is 
located in the caldera area. For these short 
traverses the technique of fixed recording units 
and moving shot points was used. The shooting 
crew operated from shallow-draft rowboats. 
Some rapid analyses of data were done in the 
field to judge whether data being gathered were 
adequate. The bulk of the data, however, was 
processed at the Hawaii Institute of Geophysics 
after the field work had been completed. 
In data processing the seismograms were first 
examined and arrival times were picked by eye. 
After rough travel-time graphs were plotted 
KeagkL' 
KAILUA 
Refuge) 
?11qws Air Force lias- 
KILCRE'ER 
WAlMANALO 
Fig. 3. Location map of refraction traverse and recording stations near Kawainui Swamp. 
