Tsunami of April 1, 1946 — Macdonald et al. 
rise, with amplitude of about one third that 
of the ensuing trough. 
HEIGHTS REACHED BY THE WAVES 
ON HAWAIIAN SHORES 
Measurements of high-water marks have 
been made around the shores of all five 
major islands of the Hawaiian group. The 
measured heights are shown on Fig. 3 to 7. 
All heights are stated in feet above lower 
low water. At each point sea level was esti¬ 
mated, the height of the high-water mark 
above that level was measured by means of 
hand level or steel tape, and the measure¬ 
27 
ment reduced by means of tide tables to 
height above lower low water. Some inac¬ 
curacy undoubtedly has entered in the esti¬ 
mation of mean sea level, but it is believed 
that the heights are probably accurate to 
within 1 foot. The levels measured include: 
points indicated by eyewitnesses as the upper 
limit of the water, lines of flotsam or swash 
marks, the upper limits of soil and vegeta¬ 
tion scouring, levels of consistent scratching 
and barking on trees, and the upper level of 
staining on the walls of buildings. 
The measured heights of high-water 
marks range from 53 feet at Pololu Valley 
Fig. 3. Map of the island of Kauai, showing heights reached by the water during the tsunami of 
April 1, 1946. Heights are in feet above lower low water. 
