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PACIFIC SCIENCE, Vol. XIX, July 1965 
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Fig. 2. Seismic reflection profiles north of Oahu. 
tion seismic measurements made mostly north 
of the Hawaiian Ridge. 
Little to no thickness of sediments is indi- 
cated in the shallow water over Penguin Banks 
southwest of Molokai. The area appears to be 
characterized by a high degree of bottom re- 
flectivity, and high reverberation level. This 
may have masked any thin veneer of sediment 
that might be present. On the island shelf 
north of Molokai and Maui and within the 
Molokai Channel, sporadic sediment accumula- 
tion occurs and varies from 100-160 m in 
thickness. This appears to be concentrated in 
pockets and channels along the shelf. For the 
most part, the bottom again exhibits a rela- 
tively high degree of reflectivity. 
Reefs are thought to be observed at the 
south edge of Penguin Banks southwest of Mo- 
lokai and at the edge of the shelf north of 
Maui. Southwest of Molokai the reef appears 
to be 230 m thick, with the top lying 500 m 
below sea level. North of Maui the reef appears 
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Fig. 3. Seismic reflection profiles northeast of Molokai. 
