The Hawaiian gazette., 1885-12-08

known TO the inhabitants only by the DrlgnI
light at night. 2. The active volcanoes have
scarcely any mOntiCules or cindercones, al
though they are represented upon the extinct
niles of Kea, Hualalai and Haleakala on Maui
3. The discharge Of lava from the open vents
Of KiIauea is nearly continuous. 4. AS con-
sequence Of the foregoing phenomena, the
mountains are very fiat. From HilO TO Kiauea,
thirty miles, the rise is about l25 feet to the
mile Mauna LUa is sleeper, averaging 4I5
feet 60 the mile above Kilauea. 1t is an clip
teal dome, seventy four miles long and fifty
three miles wide, measured at the sea level.
). The greatest popularity is the shape Of the
so-called crater DutIon uses for it the term
ouI,i,7u, a depression formed by the dropping
downward # a block of the mountain crust
iuto the cavity left 10y the escaped lava. The
Kilaura caldera is an oval pit, with precipit-
Gus sides. 300 500 feet deep, three and a half
miles long and two aud half wide. The floor
is at present nearly fiat, carrying three OPEN
ings or lakes, from which melted lava flows.
Tie most noted is called Halemaumau, the
diminished residue Of the great central lake
first described in 1928, now 900 feet long and
600 wide. A second is New Lake." about
500 feet long and 300 feet wide. originating in
1851. A third commenced to form upon the
D..
These lakes are the vents for the discharge Of
tie lava and represent the crater Of other vol
clupcs. The caldera of Mauna Loa, called
Mokuaweowco by the Hawaiians, is very like
Kiauca. being three miles long, one and three
fourths wide, and 500 feet deep. At present
no lake is present or visible in its midst. We
do not find the record of the descent of any one
to the floor of this Caldera, except Capt. Dut-
. g. L. / 4
two kinds OF lava, the pdl0eh0e and al. The
first is comparatively smooth, disposed III nu-
meruus cracked and wriDkcd hummocks,
formed as the flowing, stiliening lava gradu-
ally cooled. The cracks develop by the con-
traction induced by cooling. The "a lava is a
species Of clnker, consisting Of the toughest
kind of fragments as loosely aggregated as
gravels, whose surface is comparable with the
hackly fracture seen in broken iron. 1t issues
forth as a stream Of lavaburrs, mnch like the
flow Of burning pieces Of anthracite when the
crate is raised Similar distinctions, if OBJ
served elsewhere, have never been properly
described; and Captain Dutton has now recog-
nized streams Of "a among the later lava flows
of Northern Arizona. Dutton thinks the pa
kosl0e is the more thoroughly heated fluid, ca
pable of flowing many miles without being
in large masses nearly ready to solidify, NOV
ing slowly, like a glacier, and, as the last re-
suit of the sliding, being crushed, splintered
and fractured into these graduated fragments
When the caldera is filled to a certain height
the molten lava breaks out at variable dis.
tances from it. The 1910 eruption from XII.
lauea broke out at first six, and then twenty.
seven miles distant The noted outhows from
Loa in 1855, 1859 and 1881, came from orifcet
about ten miles from the summit, and very
few hundred feet lower than the floor of thu
| caldera. The gOw of 1865, at Kahuku, hal
been claimed as originating from each Of tn,
volcanoes by different authors. The termina
crater Is twenty-five miles from Loa, ant
thirty-thrce from Kilauca The stream started
the very hour the lava disappeared from XII
lauea. Hence, il it came from Loa, as gener
ally believed, the locality of the discharge from
kilauea has never been recognized, thougl
| probably escaping into the ocean. Hilbert,
no author has been able TO discover apy indiCa
ton Of con,emporaneous action between tn
| two caldcras When one is active the otbe
has been silent; but both seemed to have dis
charged their contents simultaneously in 1865
In this case. the island suffered greatly from
violent earthquakes just preceding the erup
tions.
HaIeakala is the name of less known ex
| tinct caldera upon the island of Mani. lint n
! greater rise than the others. Its brink at tn
highest point is 1880 feet above the sea. Tn
shape is much like that of bread letter V. Nh
| length Of the outer wall beng I6 miles, tn
width from two and a half TO four miles at tn
angle, the depth 500 to 1000 feet, and III
total area about twenty-three SQUARE miles
| Upon tue floor may be seen a dozen craters
the largest go feet high. There is no tradi
ton OF action in this caldera: but upon on
Hank OF the mountain may be seen a stone wal
oil human construction, over which lava la
ilowed, showing that extinction has occurre,
since the arrival of the Hawaiians. At th
present writing there is no known caldera o
crater larger than this in any part Of th
world.
In the chapter upon the Volcanic Problem
Captain Duticn discusses five leading theorie
OF The origin OF volcanoes, and finds no one @
them adequate TO explain all the phenomena
The first one calls in the agency Of water pen
etratiug TO enormous depths and converter
into steam. This view is sustained by III
! phenomena Of geysers. If any volcano owet
It's existence TO this cause it should be thes
! Hawaiian examples, situated in mid-ocear
The second calls upon chemical action to &C
count for volcanic energy. The third is III
ume-honored doctrine of primeval igneou
fuidity, the exterior cooled by radiation an
| the interior still fused. The fourth insist
that heat is generated at certain localities b
causes hitherto undiscovered. Local incre
menis OF heat produce all the phenomena G
volcanism." As advocated by Dutlon, anteriu
TO the Hawaiian visit, the heat originated in a
| aqueo-lgneous sCftening, or melting, of ma
terial beneath thick sediments, being eithe
central heat prevented from further radiation
or accumulated by chemical or mechanica
action. The presence Of the thick sediment
Is the essential part Of the theory, which j
now labeled an arbitrary postulate," capabl
Of explaining all volcanic phenomena, if fr-u,
! There Is not a sciniila Of evidence TO show tn
presence Of thick sediments beneath these Ia
waiian volcanoes; and, consequently, the sup
posed conditions for developing the heat ar
absent, and the theory unreliable. In faci
Professor Judd, of London, one Of the fore
most writers upon volcanism, does not eve
honor this theory by mention of it as bein
| held 10y any one. Many volcanoes derive thei
| ejecta from the base Of tertiary beds; but :hei
entire absence in the Pacific shows that tn
largest volcanoes known do not require tn
thick sediments for their activity. The fftl
theory represents that relief of pressure upo
solid rocks, heated nearly to the melting point
would cause them to liquify.
1t is pleasure to find so eminent write
as Captain Dutton acknowledging that he can
not satisfactorily ascertain the source Of vol
canlc energy, since it shows that he is not IN
duly biased by any theory; and we may expec
his statement Of the difficulties and Of the fact
10 be impartial, Pending the solution OF tn