The Olneyville times. (Olneyville [Providence, R.I.]) 1887-1917, 1908-10-23
ORIGIN OF EARTHQUAKES.
Three Great Shocks Of Past Year Caused
by Mountains Slipping.
................... ..............t....

OF this number ninetN-tour per cent.
occurred within the range OF two
marrow bands forming great circles
on the earth's surface.
According. 10 a writer in the North
American Review, San Francisco.
Valparaiso and Kingston need not
have felt surprised at their shaking
up. They have always had earth
quakes aud there Is no reason 10
think that they won't keep on having
them They are located in the most
frequently visited portions OF the
two earthquake belts
one of these belts. in which has
occurred titty-three per cent. of all
recorded shocks, is called the Medi-
terranean. IL swings roughly east
and west about the earth, and i'm
cludes the Mediterranean region,
Asia Minor, the Caucasus. the llima-
iayHs, the East Indies, Central Amer
lea and the West Indies. Where the
belt crosses the oceans little is known
about its condition.
The second belt called the circum-
pacific, almost encircles the Pacific
Ocean Passing along the Andes IL
crosses the other belt in the Central
American region. thence extends up
the western coast of North America,
passes across TO Asia along the Aleu-
tian chain. thence down through
Kamchatka. the Japanese Islands and
the Philippines, and crossing the
Mediterranean belt in the East In
a 4. ~. 1nt,
Furty-one per cent. OF all recorded
shocks occur in this belt
All the rest OF the world, that is, n
surface scores OF times greater than
the combined area of these two belts.
is the seat of only six per cent. Of all
recorded shocks. Even outside the
belts, of course, some vigorous
shocks occur. but Il may be stated
that the United States east of the
Rocky Mountains stands in rs little
danger as any portion of the earth s
su face. Only in one locality, or pos
| sibly two. does there seem good
ground for considering an earthquake
! of first rank among more than the
| remotest Of possibilities.
~ /
| Jar i'm the earth's crust will cause an
! earthquake. An explosion OF dyna-
mite starts vibrations which pass
| through the rocks as the waves of an
earthquake do.
For example, when the passage OF
| He'll Gate was cleared away some
! years ago by a great explosion the
Oh ha
! graphs at Washington In one direc-
! tion and Boston I'm the other. A
! landslide causes an earthquake; the
! falling Of the roof of a cavern Is an
! other cause. and the swapping OF
! rocks under slight strains another.
! These are all minor causes for
! earthquakes, but they account for
many of the small tremblings which
! are felt i'm limited area. A much
more important cause is volcanic ac-
! tion.
II is opular belief that all
! earthquakes are somehow caused by
! volcanic action, but as a matter OF
! fact. while volcanic earthquakes are
/ common and locally Of great violence
/
! I'm cases where the sesmOgTaphs OF
! the world record a shock, as in the
! case OF San Francisco and Of Kings
! ton. the inference Is unavoidableathat
J ~ is due go some other cause than
volcanic action
The cause OF the San Francisco
| shock was understood by all gcolog-
| tgtu A ~
| mountain chain; the rocks there are
! in a state OF strain this strain Is be-
! ing steadily increased; during the
! past history OF the mountain growth
! the strata have been broken and
! forced to move along the planes OF
! breakage or fault planes, and when
| great masses Of rock suddenly slide
/ over one another. even though the
| movement be but a few feet, the
| grinding Of the strata together must
OF necessity set the earth trembling.
Since the earthquake a State COM
mission has been carefully studying
the facts, and IL reports that for at
least 1876 miles there has been a slip,
on one side of which the mountains
have been moved bodily In relation
90 tho other side. In this instance
the movement was mainly horizontal
instead of vertical, as is normally the
case
In places the shifting amounted 10
only two or three feet, in others 10
as much as twenty feet. BY 81 roads
were dslocated, fences broken and
moved apart water pipes separated
and long burrows opened in the
ground.
The movement OF a great block OF
the earth's crust from two 10 twenty
feet. along plane nearly 200 miles
in length and extending 10 an un-
known depth, but probably thousands
Of feet, furnishes ample explanation
Of a shock whose vibrations reached
the seismographs In all parts of the
earth, and whose area OF destruction
extended 400 miles In one direction