The Washington times., 1923-09-04

I caused Oy II kldNAA6 US0u AOAsSS~
Watch that ridge"
,aEIsontaiI2 HE tasH prsass pagais fse' tse loWer w
edges of the newspaper. The height
of the ridge was Immediately In
"That," continued DIR. Reeds, ''is
isostasy, and that is what hap
pened to Japan. And it will con-
tinue to happen to Japan at in
tervals a great many years after
this generation has been forgotten
"In other words. Japan is being
pushed further and further UP out
of the sea, and the pressure OF the
rock masses probably will not cease
until an equilibrium has been at.
tained-possibly with the raising OF
the floor Of the 'tuscarora deep To
far more gradual slope from the
Japanese coast, and possibly also
with the. addition of territory %
those islands, including a linking
of them into one big island forHlA'
ton.
But that may not be for 2O,OOO.-
600 years, or some such time as
that"
Width or Rock Varies.
Continuing, DR.. Reeds explained
that whereas some of the rock seq
ments forming the japanese ISLANDS
are but a few hundred feet IN
width, at the earth's surface
though most of them are many
miles in length and depth, others
are several miles wide.
"Thus it would appear that TOKYO
and Yokohama are on the same
segment chiefly affected by the un-
derground action of isostasy, ne
went on, ''or, at least, on adjoining
segments in the area principally ols.
turbed by the mass rock pressure
below the 'tuscarora deep. II was
merely q case of one or more OF
by the pressure.
"In some earthquakes, segments
have been forced upward six feet
or more. Incidentally, segments
should not be confused with faults.
which merely are the dividing lines
between segments."
DIR. Reeds said that such an earth
quake would be impossible in New
York, Boston or the other cities
along the Atlantic seaboard, "be-
cause this part Of the world is much
older than Japan, and went through
what it is now undergoing many
ages ago."
Caused Other Qualxes.
He was of the opinion, however,
that isostasy played part in the
Chilean and San Francisco earth
quakes, because the Pacific coast is
of more recent formation than the
Atlantic, though he added that a
far greater adjustment had been
attained along the Pacific coast Of
this country than that affecting
Japan.
"You have made the action of
isostasy clear, but just why does 1t
act?" DIR. Reeds was asked. Take.
for instance. two objects OF unequal
weight and place them beside each
other. There they might remain
till doomsday, for all that one
would exert pressure laterally
against the other:
''That is true" was the reply.
'.But remember that the earth is
a globe, and that gravity pulls di-
rectly downward, toward the center
of the sphere. That being the case,
and it being considered that three.
fourths of the earth's composition
is the heavier rock below the sur
face Of the seas, there is tendency
for the heavier rock masses, con-
tinually pressing against the lighter,
to force the latter upward.
Earth's Crust Equalized.
This is particularly where the
lighter rock is concerned in extremes
OF rises and depressions in the
earth's crust, as in the case OF Japan
and the 'tuscarora deep There II
lie that isostasy. acting literally
endeavors to equalize the earth's
crust. Corosion has the same goal on
land, but there the principle IL OF
| wearing down rather than forcing
| up.
the Greek word 'Isos,' meaning
equal. and is defined~as the theo
retical condition OF equilibrium
! which the earth's surface tends. tc
assume under the action OF ter
restrial gravitation, as affected by
the transference of matter from
regions of denudation to those oi
deposition, and by differences 1r
density in various portions Of the
earth's mass near to the surface"
Discussing volcanic action, DR..
Reeds said that leading geologists
have virtually abandoned the theory
that major earthquakes are caused
by eruptions. Rather, he said, the
earthquake is the cause OF erup-
ton.
Japan he said. literally rests
on a mass of molten rock, many
miles below the surface and caused
by friction due to the action OF
isostasy. It is when isostasy exerts
sufficient pressure on such molten
rock that 1t iss forced upward
through rock conduits to the vol
canic craters, and an eruption oc.
ours.
Whether an eruption Of Mt. F'uji
and the other japanese volcanoes is
to follow the present disaster will
depend on whether the action OF
isostasy causing the quake struck
deeply enough to exert any consid-
cradle pressure on the molten mass
below"
FeIons Praise Oregon.
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