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PACIFIC SCIENCE, Vol. XVII, July 1963 
local deflection by the islands. It was probably 
typical of the trade-wind period of the year. 
May through September, when the winds blow 
from the northeasterly quadrant 80-9596 of the 
time. From October through April the trade 
winds still blow from the same general direction 
most (65-80%) of the time (Blumenstock, 
1961). The wave pattern was more complex 
than anticipated, with three trains of 7-sec waves 
and several trains of about 1-sec period. Most of 
the wave energy was in two trains coming from 
the east and southeast, evidently produced by 
the trade winds, and agreeing well with the 
general observation of predominant waves from 
the east in the Hawaiian region. Shore types of 
the islands appear to be closely related to degree 
of exposure to these waves. Rocky shores are 
generally in the most exposed sectors, sandy 
shores are in the immediate lee of prominent 
headlands, and muddy shores are in the most 
protected sectors. Recent changes of sandy shores 
may be due to possible long-term changes in 
the trade winds, with attendant changes in the 
waves produced by them. 
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Blumenstock, D. I. 1961. Climate of Hawaii. 
U.S. Dept, of Commerce, Weather Bur. Cli- 
matography U.S. 60-51:1-20. 
Bowditch, N. 1943. American practical navi- 
gator. U.S. Navy Hydrogr. Off. 9:1-387. 
Dietz, R. S., and E. C. LaFond. 1950. Natural 
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Emery, K. O. 1958. Wave patterns off southern 
California. J. Mar. Res. 17:133-140. 
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Hawaiian Islands. Pacif. Sci. 10:382-402. 
, J. I. Tracey, Jr., and H. S. Ladd. 1954. 
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Geol. Survey Prof. Pap. 2 60- A: 1-265. 
Ewing, G. 1950. Slicks, surface films and in- 
ternal waves. J. Mar. Res. 9: 161-187. 
LaFond, E. C. 1959. Slicks and temperature 
structure in the sea. U.S. Navy Electronics 
Lab., San Diego Res. Rept. 937: 1-35. 
Munk, W. H. 1947. A critical wind speed for 
air-sea boundary processes. J. Mar. Res. 6: 
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Shepard, F. P., G. A. Macdonald, and D. C. 
Cox. 1950. The tsunami of April 1, 1956. 
Bull. Scripps Inst. Oceanogr. 5:391-528. 
Wentworth, G K. 1949. Directional shift of 
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