Fault at Waimea, Oahu — Palmer 
87 
continue below sea level a short distance, 
and a wave-cut bench would extend seaward 
from the foot of the cliff. If after the cut¬ 
ting of the cliff the dome-shaped island were 
faulted, the cliff along the raised part would 
of course have its crest higher than the cliff 
crest on the lowered part, as is suggested in 
the lower sketch of Figure 3. If there were 
in addition a lowering of sea level or a rais¬ 
ing of the whole island, the wave-cut bench 
might be exposed and would be higher on 
the upthrown block than on the downthrown 
block. 
Fig. 3. Diagram to explain how a fault may 
change the height of sea cliffs. 
At some time in the past, waves cut con¬ 
spicuous cliffs along this part of the shore 
line of Oahu, just as waves have cut the 
present striking cliffs along the Hamakua 
Coast of the island of Hawaii. Later a lower¬ 
ing of sea level exposed the wave-cut bench, 
on which reefs had been built in the mean¬ 
time by corals and associated organisms. 
Streams carrying detritus from inland have 
built alluvial slopes on the emerged plat¬ 
form. As one drives along Kamehameha 
Highway, which is on the platform and in 
general fairly close to the shore, one can see 
that the wave-cut cliffs are decidedly higher 
northeast of Waimea Bay than southwest of 
the bay. This difference in heights of cliffs 
agrees with the hypothesis of a fault at Wai¬ 
mea Bay. 
CONCENTRATION OF PERENNIAL 
DRAINAGE 
Streams on a symmetrical volcanic dome 
tend to take courses that radiate from the 
central summit, somewhat like the spokes 
of a wheel, as is suggested by Figure 4, a 
Fig. 4. Diagrammatic map to explain the con¬ 
centration of drainage by a fault. 
diagrammatic map of the stream courses on 
half of a dome-shaped island. But if the 
island is faulted, some of the stream courses 
may be diverted, as is shown at the left in 
Figure 4. The fault is shown by a straight 
line with short perpendicular lines on the 
downthrown side. The fault is seen to divert 
the headwaters of four streams into one 
course, which is thereby given an unusually 
large volume of water and an increased 
ability to erode. This appears to be what has 
happened at Waimea Canyon, Kauai, where 
the stream has cut that remarkably deep 
canyon. The lowering of the stream bed, 
partly by downfaulting and partly by its own 
erosion, has brought it closer to the water 
table, so that the stream is more generously 
fed by underground water at all times, and 
receives some ground water even in the drier 
seasons. 
At the right in Figure 4 another fault is 
shown, but one about perpendicular to the 
shore line. Since the course of this fault is 
radial and essentially parallel to the radial 
