The Hawaiian gazette. [volume] (Honolulu [Oahu, Hawaii]) 1865-1918, 1889-03-26

I planaJiOnS. hNurOSUallC pressure II
out of consideration, inasmuch as
/ the fountains are at the summit OF
the dome, and at times throw theil
/ Jets 80 to 100 feet above the noun
/ tain's top-over 1900 feet above the
sea-level.nI
tAmerican Journal Of Science, Vol. xNxy1.
August 1855, PIP. s.. 81.
But why should hydrostatic pres
sure be thrown out of consideration ?
1t is true that we do not see the head
of liquid above the fountain as we did
in the great lava fountains which
were thrown up on the sides of Mauna
Loa below the level of the bottom of
the summit crater; but when the solid
floor of the crater stops the steady rise
Of the laYas in the column pressed up
by the weight of the earth's crust, it
only requires an opening to be made
in that floor for the lava to spout up
just as the water sp0utS from the
nozzle of force-pump. 1t might be
supposed that we should then see the
piston of the force-pump-the earth's
crust-descend but a moments re-
Election tells US that such a movement
would be quite beyond the reach of
observation, for if we assume that the
descent of only 100000 square miles
of the bed of the Notwithstanding
say 500 miles from Mauna Loa in
each direction-was concerned in this
piston-like action, and that the lava
expelled in half a century was equal
TO a cubic mile, ii would only require
the descent of the crust to the distance
r Of -
over 6-l00 of an inch about l-16) in
half n century, an amount of subsi-
dence which would be quite insen-
sible, but competent to effect the
work. 1t is what in common parlance
would be called a pressure rather than
3 movement of the crust, and may be
looked upon as 4 particular case in
the principle or primary causen of
volcanic action adopted by Joseph
Prestwich, and where he quotes Cor
der, who calculated that a radial
contraction so minute and impercep-
tible as one millemetre (0.0397 inch)
would suffice to supply matter for five
hundred of the greatest known vol
canic eruptions.nz
Sociology by Joseph Prcstwich, MA, FRS.
F.G.S oxford, 1886, page ZIG
All this leaves room for the action
Of steam or expanding vapors in these
or other volcanoes of the globe to any
extent that the evidence in each case
may require; and this action is, in
many instances, tremendous-as ut
Krakatoa and Tarawera. Hydrostatic
pressure first brings the molten lavas
into 4 situation where they can be
acted upon by fresh water or by sea
water; but there is nothing incon-
sistent with the principles of hydros-
tatics in the view that this force may
raise the molten matter on which the
earth'S crust rests to the tops of the
mountains Of the globe. 1t is
merely a question OF the relative den
sity of the solid crust and the molten
whenever the latter has
an opportunity presented to it to rise
freely in 4 assure; "a hydrostatic
problem n-as Captain Dutton calls it
-"Of the simplest ORDER This
simple problem seems, on Hawaii, to
be as little complicated with the
effects of elastic vapors as could in
any actual case be expected.
If, then, we may follow such dis
physicists and biologists
as Beaumont, Cordier and PTestwich,
in this view of the primary cause of
volcanic action, the phenomena pre-
scented by Mauna Loa and Kilauea
involve no insupeTable difficulties,
and there should be observed eer-
tain sympathy in the action of the !
two volcanoes not, as commonly |
expected, that when an outbreak |
takes place on the sides of Mauna
LOa, Kilauea or rather Halemaumau,
should commence to overflow, but, as |
the story Of the two VOLCANOES indi- |
Gates, the lavas having gradually |
risen in Kilauea to high level, an |
outflow somewhere on either noun |
tain may occur. At the moment of |
such outflow the lavas in Kilauea |
either remain quiet-that is, do not
rise-or they subside, just as a new |
lowing artesian well may lower the
.eyel of its neighbOrs. When the out
low on Mauna Loa ceases, the lavas
IN Kilauea commence to rise again,
md presumably also, judging from
results, those in the conduit of Mauna
Loa, under the constant, but slow,
action of the pressure or weight of
he earth's crust.
1t is now Il little over two years
.ince the last eruption on Mauna Loa
,ccurred--the outbreak at Kau of jan
larry 10Th, lSS7-during which time
hat mountain has made no sign. 1t
5 true that steam has been seen rising
rom the summit and from some of
he assures on the sides; but this may,
md probably does, only mean that
IN extra quantity of rain-water or
netting snow has found its way to
he rocks beneath which retain some
f their heat from the last eruption.
so lava has been known to be
iected.
Kilauea, in the meantime, has been
its regular course, that is,
he molten lavas have been rising
teadily in Halemaumau, and bring
NC up its cone OF debris with them,
oating it bodily up with the floor of
he great crater Of this spot. The
ava has not only, since the subsi-
ence of March the 9Th, 1856, filled up
he great triangular pit then formed,
nut Halemaumau lava lake and those I
Il the neighborhood subsidiary to it, |
ave lately been from time to time
curing their contents over the
eneral floor Of the crater. Thus
lilauea is now fuller of solid lava /
han ever before known; and if the
Use of the lavas and the outflows con-
niue, they threaten to raise the
end of the floor so much
hat the lava may overflow the outer
inn of the great crater.
w. l.. GREEN.
Honolulu, February Is, 1889.
NnrE.-The Hawaiian Government