The Hawaiian gazette., 1906-05-29
THIS IS LIKE
VOLCANIC
ACTION

SANTA ROSA, May is. - George
Madeira. a geologist and mineralogist,
who was selected by State Mineralo-
zist Lewis E. Aubrey to gather and
arrange the mineral exhibit of this
state at the st. Louis Exposition, has
made an interesting discovery in re-
gard to the earthquake, and advances
a new theory as to its origin.
Near the Maacama Schoolhouse,
above Healdsburg. he found some phe-
nomena in the shape of one of three
hills blown entirely away. Madeira's
theory is that the quake was caused
by an internal explosion of gas and
that the missing hill offered the least
resistance to the exploding forces and
was blown away.
lie found that its formation was of
light soil, and traced it almost to San
ia Rosa, its origin evidently being vol
canic to a great extent. This he be-
lieves to have been a fault of the
earth and caused the settling of places
in this city and the country south of
here. Madeira says:
"The scene of the explosion is d.
rectly in front of the home of Hugh
Simpson, and his house just escaped
the rapidly moving mass. Before the
earthquake three conical wooded hills
rose above the small fat lying between
the creek and the base of the hills.
The third or highest and most easterly
of these hills was the one that received
the full force of the internal explosion
and was in consequence thrown north
ward in a mass, carrying everything
growing upon its surface and deposit
ing. the material in broken masses of
huge proportions for distance of 1000
feet and a width of $50 feet.
"The material of which these several
hills are composed Is the deposit OF
some extensive volcanic action OF pre-
historic time. 1t is wholly composed of
iapi finely comminuted volcanic dust
and a coarser variety containing sand
and lapi mingled. The qualification in
dictated that much of the underlying
material was erupted as q dry, hot
volcanic ASIA light, fluffy material,
oluish-gray in color. The coarser ma
terials which were deposited over the
iapi material, are stained with oxides
of iron and show lines of horizontal
stratification, but like the underlying
material is extremely friable and of
slight specific gravity.
I'm other words, the materials have
the appearance of sandstone, and the
huge broken masses are at once taken
for that substance until examined, their
extreme lightness in weight being
surprise. This volcanic material forms
q continuous chain of low mountain
ridges extending southwark to within
one mile of Santa Rosa The extreme
iightness of the material at the par
ticular point of explosion indicates the
point of Weakness and the slight re-
sistance to the underlying pent-up
gases which, in the cataclysm, were
SHOT into the spaces above.
climbing over the huge broken
masses we reach what appears to be
the summit of the outburst-a mass
of surface ground, fissured and broken,
but with the trees still standing in po-
sition. The explosion opened the fis-
sures to a great depth. running north
twenty degrees west and south TWEEN
ty degrees east. The masses were
blown out on each side of this middle
ground, that to the north of the divid-
ing line being blown toward and across
the creek, while to the south of the
middle, line the material was shot from
a deep crater into the air. much of 1t
falling back into the excavation, where
it lies in broken masses mingled with
the trees that once adorned its sur
face