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K
iller quakes have hit the bead–
lines with dis turbing fre-
4 uency in recen t months.
"Gua tema la 's 39 Second Eternity
of Terror. " Death T o ll in Hundreds
in It a ly."' " 10.000 Left Homeless by
Soviet Quake,' ' a nd others in Mexico.
Ba li, and New Guinea hit in rapid
succession. Then Chi na was devas–
tated by the most gigamic quake of
the decade, killing tens of thousands.
Even before the China disaste r,
ea rthqu akes in 1976 had killed over
24,000, making it the dead lies t year
for quakes since 1970. according to
th e U.S. Geolog-
ica l Survey.
ti ve in strume nts. S till. a bout a
dozen or so "major" q uakes
(7
to 7.9
on the Richter Scale) occur yea rly.
A "grea t" quake, such as occu rred
in San F rancisco in 1906 and
in
Alaska in 1964, measures 8 or more
on the same sca le. Yet, even " mod–
erate" qua kes measuring little mort
than 6 can cause extensive damage
in areas o f poor cons truction.
In th e last ten yea rs majo r quakes
have wiped out who le regions and
villages in Sicily, Turkey, Pakistan.
and Lat in America a nd severely
jarred many other areas around
SEISMIC RISK
Major
D
Moderate
D Minor
D None
quakes is plate tectonics. At least a
dozen g reat crustal slabs 80 or so
miles thick have been found cov–
ering the planet. These huge plates
a re floating on th e earth 's semi–
molten ma ntle a nd are kept in mo–
tion by powerfu l interna[ fo rces
which are not as yet very well un–
de rstood by geologists.
Imperceptible to human senses in
mos t cases, these pla tes a re con–
stan tly interacting at their edges -
bumpi ng, grinding, pull ing apart or
plunging benea th one a not her -
produci ng tremendous strains from
a few to severa!
hund red mil es
below the sur–
face.
The ea rth–
q uake-p lag u ed
J apanese isla nds
a re the summ its
of a young and
s till evo l ving
mountain chain
which marks t he
bo u ndaries o f
severa] of these
plates.
Frict ion fre-
Map rellects the lntenslty of past shocks. not lhe frequency
1ns tin c t ive ly
we don' t like to
think abo ut
ea rthquakes hap–
pening t o us.
Yet hundreds o f
m illi o n s
o f
peop le live in
m a j or ea rth–
quake belt s.
(See ma p. ) And
othe r areas -
se em in g ly im–
mun e
fr o m
qu akes - may
none th eless be
subject to dam–
ag in g tremo rs
ca u se d
by
stresses bui lding
u p ove r ce n–
turi es of time.
que nt ly locks
~
sec ti ons of these
~
h uge p la tes in
~p l ace .
ca u s i ng
~
grea t strains that
~
udden ly release
~
themselves as
L-------------------------------'
ea rt hquakes.
Fa ilure to face the possi bility of
expe ri enci ng a n earthquake crisis
ca n lead to uncontroll ed panic, im–
mobi lizing fear, and da ngerous ru–
mors, as well as disregard for bas ic
safe ty precau tions when a q uake
bi ts. The tragic result is ma ny un–
necessa ry injuries, dea ths, a nd prop–
e rt y losses a dd e d t o d i s a s ter
columns.
Few Areas Untouched
One has but to map the geography
of la rge earth tremors or major
qua kes in the las t decade a lone to
rea lize that ve ry few regions of the
earth have been untouched by up–
se tting j o lts if not some type of tra–
g ic destruction.
The truth is tha t te rra firma , in an
absolu te sense, is a my th. Thou–
sands of tremo rs occu r da ily. Most
are detec table only wit h ultra-sens i-
20
th e Circum-Pacific " Ring of Fire ...
In this same period. temblors
ha ve been felt in England, France,
Austria. a nd o ther parts o f Europe.
All but fo rgotten to most Ameri–
cans is the tremor th at jolted 23
Midwes t States in 1968. Cei lings
a nd wa lls cracked , windows broke,
chimn eys toppled, and ta ll buildings
swayed over a wide area.
Ea rthquakes east of the Missis–
sipp i Ri ver are much less freq uent
and in mos t cases milder than those
in Western States. Nevert he less, a
three-hundred-m ile str ip of the cen–
tra l Mi ss iss ippi Yall cy. Boston.
Cha rles ton (South Ca ro lina), and
oth e r East Coast a reas are vulner–
able to majo r qua kes, say experts .
Why Earthquakes?
The most wide ly acccpted theory
expla ining many, bu t no t a ll , earth-
In Ca lifornia. two grea t plates are
slid ing past each other. A sliver of
Californ ia coastal area is moving
nort hwest a few inches a yea r. The
fa mous San Andreas Fau lt marks
the edges of these two p la tes.
Unfortunately, a sec tion of this
fau lt near Los Ange les (a n area in–
cl ud ing the " Pa lmd a le Bulge" tbat
has risen a foo t in the last fiftee n or
so years) and ano the r near San
Francisco appear locked while o ther
sections of the plate have moved
a round twenty fee t.
For years a major eart hquake has
bcen fo recast for Cal ifornia on the
order of th e 1906 magnitude.
"There will be a big eart hquake in
California sooner o r later," sa id one
otficia l of the U.S. Geological Sur–
vey.
" lt
could be decades away, bu t
it could occur tomorrow."
(Continued on page 24)
The
PLAIN TRUTH September 1976