The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1885-1921, 1906-09-07


largement the pit-erater increases in
size That which we observe with the
smaller pit-crater may be noticed in
operation around the circumference of
the great basin of Mokua weoweo. Here
and there huge slips have taken
place and thousands OF tons OF rock
have been precipitated into the basin
and IL is in these localities that a Ill
rect descent may be made into the
deepest part OF the basin by Chamber
ing down over the taius thus formed.
Deep assures traverse the ground on
the mountains summit. running paraI-
lei with the margin of the great basin.
and often only a few yards from its
edge Such may be frequently observ-
ed around its borders, and they mark
the site Of future subsidences on a
large scale. One such slip took place
on August Is. 1897 or, rather. Sc
ries Of slips occurred during the day.
the locality being on northeast border
OF basin. Each slip was followed by q
dense brown smoke. produced evidently
from the dust. ana there was finally
left a big gap in the wall of the basin.
On subsequently visiting the locality
I found the gap TO be 500 or 500 feet
wide and that previously an extensive
slip had taken place just south OF il.
As is wei observed by Captain Dut-
ton, the cliffs are so rifted with cracks
that they appear liable TO fall in at
every moment, and he notices the evil
dence OF numerous s1ps. such as I have
above mentioned. All these great
pits" he remarks-and he is here also
abiding 10 the craters of Kilauea-
give indications Of progressive en-
largement by the successive cleavage
and dropping in of large spalls faulted
from the faces OF the encircIing cliffs .
/ Is thus apparent that Captain Dut-
ton would consider that the great
crateral basin on the summit Of Mauna
Loa was at one time considera bly,
smaller than il is at present; and since
my conclusions as 70 the enlargement
of the basin by the falling in of the
sides receive support from a geoIogist
of such experience. I do not hesitate
TO utilize them in the further develop
nent OF my view that in the great
basin OF Mokuaweoweo We have the
result of the coaIescence Of a line of
pit-craters followed by the lateral en-
largement OF the cavity produced. a
process that is now illustrated in its
earliest stage by South Mokuaweoweo
But curious point now presents it
self The effect of such a process OF
progressive enlargement by the drop
ping in of large portions of the walls
Of the vent would be to block IN lis
crater with its own debris. The door
of MokUaw eoweo, on the contrary. dis
plays a clear expanse Of solid lava. and
the effects of the slips are seen
only at its sides However, during
periods Of eruption the floor Of lava
reliquefies to a greater or less extant.
and the talus OF debris that has been
precipitated into the crater is in course
Of time remelted IN the lake Of molten
lava This huge cavity may be iIzen-
ed now 10 malignant ulcer that Is
ever increasing It's area and is IN
checked D. a..y process OF repair. Pro
vided the volcanic forces do not be-
come extinct, it viii ultimately be re-
duced TO the condition now presented
by the summit OF Mauna Kea: and lftef
the subterranean fires have barEt
themselves out. the future geol0gist
viii wander over its surface searching
vainIy for a crateral cavity in the il
Irregularities Of its degraded surface.
(c) THE AREAS MARKED BY THE
CONTINUOUS DISCHARGE OF HOT
VAPORS THAT EXTEND NORTH
EAST AND SOUTHWEST FROM
THE GREAT BASIN OF MOKUA-
WEOWEO--In these areas the alter
alton OF the lava surface and the con-
slant discharge OF water vapor and
other fumes from cracks and assures
indicate the recrudescence of volcanic
heat outside the limits Of the great
basin. As is remarked below, however,
the relatively low temperature lndi-
Gated by thermometers placed in the
assures gives no Indication of the fierce
heat that once prevailed at the sur
face. Whilst in some places. as the
result Of continued vapor-action, the
Iava-rock Is much deconposed. in
others II has q revitrified appearance
and is very brittle. an effect indicative
Of a temperature far higher than that
prevailing II the assures from which
the vapors are Tow discharged. In a
similar fashion is 10 be explained the
occasional revitriication of the borders
of these cracks and assures; whilst
red sflieeous incrustation that at times
lines the sides of assures. giving vent
10 water-vapor at temperature far
below the boiling point could scarcely
have been deposited under the present
relatively cool conditions
The southwest area is more extensive;
II Is here that the effects above noted
are more apparent. During clear.
sunny weather, when the air is very
dry, steam can only be seen issuing
from a few localities where the is
sure temperature approaches the boil
ing point; but in cloudy, damp wealth
er. when the relative humidity is high.
the whole AREA smokes and one OBJ
serves 10 ones establishment that
district previously rraversed in dry
sunny weather without displaying any
vapor TO the eye IS nog -dIscharging
Eyater-vapor from every crack and fs-
sure Over the great part OF this
southwest arm. where the continual
discharge Of water-vapor became evil
dent only IN damp weather, the TEN
perature OF the assures was only 1o3
deg or 10z deg. F; but in q few 10
calities. where Il rose 70 $50 deg. and