Eruptions of Kilauea—POWERS 
is 6 inches thick at B.M. 3,633 where the belt 
road climbs onto the edge of the Keamoku 
flow 2 miles west of the crater. At F in Figure 
1, east of Cone Peak, the section shows oxida¬ 
tion of the upper members and consists of 4 
inches of dust to fine sand, 1 inch of pisolitic 
dust, 2 inches of laminated dust on coarse sand, 
and 1 inch of medium-sized lithic sand. 
The time intervening between the thirteenth 
and the sixteenth eruptions was long enough 
for a vegetative cover to develop on the south¬ 
east rim. The fact that oxidation is deeper (in 
the leeward sections) on the deposits of the 
fifteenth eruption than on either the thirteenth 
or fourteenth suggests that the greater part of 
the time interval occurred between the fifteenth 
and sixteenth eruptions. 
The deposits of pumice, mixed with a few 
lithic fragments, of the sixteenth eruption are 
concentrated to thicknesses of 21 inches on the 
south rim near Keanakakoi. At the edge of 
the humid area (S.E. Rim 3,775 in Table 2) 
4 inches of this pumice are topped with a good 
humus layer. Elsewhere the surface shows much 
erosion and oxidation of wind-blown surface 
material and carries abundant drift pumice and 
Pele’s hair. 
The remnant rim deposits of the seventeenth 
eruption range in thickness from 6 inches on 
the northeast rim to 41 inches on the south¬ 
west rim (Fig. 2E) and are sufficiently well 
preserved to suggest an appraisal of the explo¬ 
sive phases of the eruption. After an assumed 
preliminary stage which left no record on the 
rim, the first (recorded) phase was the most 
violent phreatic explosion of the eruption and 
was followed by a pause in which rains cleared 
the air of dust. This is suggested by the basal 
layer which is found as follows: 3 inches of 
lithic fragments ranging from coarse sand up 
to 3-inch diameter (a few blocks exceeding a 
cubic foot in volume) capped by a top film 
of fine sand and dust on the northeast rim; 24 
inches of lithic fragments ranging from a quar¬ 
ter inch up to 6 inches (a few blocks of as much 
as 4 cubic feet in volume) capped by 1 inch of 
287 
pisolitic dust on the southwest rim; and inter¬ 
mediate thicknesses of similar materials on the 
southeast and northwest rims. The second phase 
included at least four explosions following one 
another so closely that the air was not cleared 
of fine dust between them. The deposit on the 
northeast rim consists of four layers of coarse 
to fine lithic sand totaling about 3 inches, and 
on the southwest rim consists of four layers of 
lithic lapilli (up to Vz inch in diameter) grad¬ 
ing into coarse lithic sand totaling about 15 
inches in thickness. The third phase included 
one explosion followed by rains localized on 
the leeward side of the crater. This last explo¬ 
sion deposited a thin layer of lithic sand grad¬ 
ing into about an inch of non-pisolitic dust on 
the windward rim and 6 inches of lithic lapilli 
and coarse lithic sand capped by 4 inches of 
pisolitic dust on the leeward rim. 
No humus formed on these deposits on the 
windward rim, but the surface features indi¬ 
cate wind work, crustation, and oxidation char¬ 
acteristic of exposure for an interval at least of 
some years’ duration. Pumice, Pele’s hair, and 
Pele’s tears scattered on the surface indicate 
lava fountaining during the interval. 
The deposits from the eighteenth eruption 
range in thickness from 2 inches on the wind¬ 
ward rim to 20 inches on the leeward rim. A 
possible separation of the explosions is again 
suggested by the details of the section on the 
southwest rim. At the start of the eruption, 
four relatively small phreatic explosions de¬ 
posited a total of 10 inches on the southwest 
rim made up of four layers of coarse lithic sand, 
each capped by lithic dust, and a total of 2 
inches of pisolitic lithic dust on the windward 
rim. Two more phreatic explosions deposited, 
respectively, a 4-inch and a 2-inch layer of 
coarse to fine lithic sand on the leeward rim 
and a 1-inch layer of pisolitic dust mixed with 
coarse lithic sand on the windward rim. Per¬ 
haps both of these phases occurred during trade- 
wind rains. The last explosion deposited an un¬ 
sorted aggregate of lithic fragments in a matrix 
of tan pisolitic dust all around the rim, ranging 
