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Earthquake!
Earthquakes are very much a part of life in California
they are an integral part of everyday life and culture. Dozens
of tiny 'shakers' rattle the state each week, unfelt beneath
your feet, through the dozens of faults that crisscoss the
West Coast. Locals take them in stride and although they fear
the 'Big One' (the predicted catastrophic quake that is expected
sometime in the future), small earthquakes are laughed off
and joked about (to the amazement of wide eyed visitors).
San Francisco is more famous for them than LA, having
experienced the 1906 and 1989 quakes that devastated the city.
The southern part of the state is also full of faults and
earthquakes have occurred there, shaking San Fernando
in 1971 and Northridge in 1994. While the San Andreas
Fault is the primary location for earthquakes in California,
(and is so large its visible from the air) dozens of smaller
faults are just as dangerous and its these fractures that
make the state such an active place, geologically.
What's an Earthquake?
Earthquakes occur when tectonic plates slip after years of
stress and pressure have kept them locked; the resulting shockwaves
are the earthquake that is often preceded by foreshocks and
followed by numerous aftershocks. The 1989 Lom Prieta quake
in San Francisco had more than 30,000 aftershocks and moved
the entire San Francisco Bay area by more than 3 feet northwards.
The earth is always on the move, from millions of years ago
when the world was just one land mass to the many continents
we have today.
Strange 'shakers'
Strange things can occur when earthquakes strike including
liquefaction that causes buildings to sink into their foundations
and harmonic resonance where the frequency of the earthquake
matches the building's height and the building is instantly
destroyed.
After any major quake strange personal stories also emerge
of people thrown off their feet and bounced off walls while
seeing 8 foot waves in their swimming pools before the water
crashed into the house; others have witnessed 4 ft waves in
solid ashphalt and seen ocean waves at the beach actually
reverse as the quake strikes. At home people have seen whole
walls torn free while crystal glasses a few feet away have
survived, and others have seen neighbours houses collapse
while they didn't even lose a single piece of china. Locals
also call any dry, hot and totally still days 'Earthquake
Weather,' (like that on October 17th, 1989) as a perfect time
for a shaker.
Predicting and Measuring 'Quakes
Quakes are measured on the Richter Scale, which is
an exponential scale developed in 1935 by Charles F. Richter.
This means that a 6.0 earthuake is not twice as strong as
a 3.0; its actually more like 30 times stronger. Ask a Californian
after a minor quake what the magnitude was and chances are
you'll get a pretty accurate answer; experiencing these 'shakers'
so frequently many are able to get the strength on the nose
before the geologists do.
Earthquake prediction has not been as successful as hoped,
and while speculations as to which fault will slide next do
exist, they tend to be percentage chances on specific segments.
For example, the fault that slipped in 1989 had a 90% chance
of a 7.0 quake in the next thirty years. In that case the
scientists were right; but the 1994 Northridge quake came
as a complete surprise.
How to Survive an Earthquake
Earthquakes are nothing to be afraid of; if youre lucky (or
unlucky) enough to experience one it won't do more than rattle
the windows and teacups than cause injury and will certainly
make for a more memorable 'California' experience than the
earthquake ride at Universal Studios. However remote a chance
it is essential to know what to do if the 'Big One' or even
a moderate quake strikes while youre in California:
If you're indoors, immediately upon sensing the earthquake
move away from windows and heavy furniture and get to a doorway
as soon as possible; alternatively get under a sturdy desk
and hang on because the shaking can be violent and often involves
movement that is side to side, up and down and often all at
once. Shield your eyes from falling debris and face away from
windows that can explode; cover the back of your neck with
your other hand to prevent spinal injuries from falling objects.
If you're outside, move away from large buildings and lie
flat on the ground away from power lines, bridges and tall
trees with your hands over your head covering it from debris.
If you are driving, stop the car as soon as possible staying
away from bridges, overpasses and tall buildings. Stay in
your car.
Once the shaking has stopped DO NOT run out of the building
as debris can be still falling its better to wait and leave
when it is safe. If youre outdoors stay away from buildings
in case of aftershocks. If youre driving go extremely slowly
as the quake may have damaged roadways.
Every phonebook in California has earthquake safety information
and can be a valuable resource if a quake did strike while
youre there.
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