The National tribune., 1906-09-06

( 7>N
LINE OF THE GEOLOGIC FAULT
WHICH CAUSED THE SAN FRANCIS
CO EARTHQUAKE
noes and earthquakes are incessant. So
in Japan, and in that country is the
earthquake of most frequent occur
renee; indeed, there are seldom fewer
than 500 in a year.
The Earthquake Line.
Along another well-defned line are
earthquakes most common. There is
seemingly depression. a sort of ditch.
almost completely around the earth
traceable through the Mediterranean,
the Atlantic, the Antilles through PAN
anna and the Pacific. and on that line
is veritable chain of volcanoes. So
we find adjacent territory most fire.
quently "quaked." Lisbon, Algeria
Provence, Naples. Sicily and the Greek
Archipelago have been devastated time
and again by appalling cataclysms. The
earthquake in Lisbon in 1855 destroyed
80, 900 lives; Sicily lost 0,OO0 lives; the
earthquake in the Isle of Ischia in 1893
was terrible one, and Peru, on that
same line. Is most frequently shaken
and disastrously.
Three distinct types of earthquake
have been defined by scientists: the YER
tical by which buildings are literally
thrown in the air. or at least where no
lateral movement Is evident, and they
collapse upon themselves, as does a
wet rag held in the air and dropped;
the horizontal movement that produces
sort of tortional twist; lateral shocks
that throw all vertical bodies out and
in the one direction (the first shock of
San Francisco's great earthquake was
OF zach naturc). The last of the three
clas =es is the undulatory shock, sort
of cscillat:ng effect, as if one were on a
II IoIbicd sea. This last is the kind os
sho X that twists railways into the ap-
pearancc Of im:nensr scrpents; such an
earthquake was JapGn's of 1891.
Some ere cf very few moments dura-
tior. and others are series of repeat
ed shocks. or possibly one long one Of
even days duration. in 1881 there was
one OF but 16 seconds ut Casamicciola,
but it destroyed 100 houses and $500
people were killed. Some have lasted
weeks and even months. In 1866 in
Japan there were 10S distinct shocks in
one weeks time; in Hawaii, In 1860,
1000 shocks were felt during the month
Of March. while In the great earthquake
in Japan in 1891 there were 1868
shocks in l2 days, while the very scri-
Gus shock that ravaged Nice in 1886
lasted but one and one-half minutes
Naturally, these great upheayals and
disturbances change the visible aspect
of mother earth. the profiles of noun
tains are modified, vast crevasses occur
and valleys are still more depressed,
| isia nds are engulfed and new ones
spring into existence.
Such seismic disturbances are felt
over Il very wide extent of territory
The Lisbon earthquake of 1856 was felt
| over a region 1900 miles square, while
that cf 1884, that had for its center
AnGalusia. was felt even in Rome. San
| FIR; ncisco's quake was very clearly re-
cor 'c1 on the seismograph here In
Wa =hington.
| The seismic waves are transmitted
along the earth's surface at varying de.
grees Of speed, depending somewhat
upon the nature, the refractoriness of
the formations encountered; 1900 feet
a second to 1900 feet in the same
| period of time are the two known ex-
tremes.
Sand and alluvial formations are the
least propitious Of soils. Earthquake
forces seem to lose their power in sucI,
ground. The more dense clays and
| rocks of certain natures seem to trans
nit these shocks with the greatest vio-
| lence and speed. 1t was such q wave
that destroyed the port Of Callao in the
| 18th century, throwing laden ships a
considerable distance in shore. In ia
| pan in 1896 a tidal wave caused the
destruction OF 10000 people. and ouy
own country has not been entirely free
of such aquatic disturbances, even In
recent years.
Our poor little crust has been torn
and racked by the strain of enormous
and unknown forces for aeons of time;
1t has shrunken by the gradual process
Of cooling: radical changes have oc.
Cured: whole mountains have crum.
bled and been carried into the sea OF
into valleys. making millions Of tons OF
additional weight at points not thereto.
fore SO weighted, and coast rivers arc
continually washing away their shores
thus accumulating vast deposits at their
mouths, mutations being ever wrought
While scientists may debate as to their
cause, the fact remains that our crust
is an exceedingly thin one and far from
stable. and that our tenure or leasehoid
upon it's surface Is one than can be
wiped out at any moment. literally ex.
tinquished. rendered null and void. aad
with that nullifcation may also go our
little lives. so very dear to us, but 10
which we are attached by. oh. SO sien-
dor fhraaHf