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Tsunamis
are a Distinct Possibility for Both Coasts of the U.S.
by SixWise.com
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The
undersea quake that hit the Indian Ocean on December 26, prompting
the tsunami that has wreaked havoc on southern Asia, is a
poignant reminder of the fragility of human life and our utter
reliance on nature’s cooperation to survive.
The
death toll from this horrible tragedy has risen to over 120,000
people as of this writing, making it one of the worst disasters
in all of recorded history.
In
Indonesia alone, where the worst damage occurred, more than
80,000 people have died. Eleven other nations across southern
Asia and East Africa, including Sri Lanka, India and Thailand,
have thousands missing and are gripped by fear of more deaths
that could be caused by disease from unsanitary conditions.
The
catastrophe has prompted what some are calling the biggest
relief effort the world has ever seen. Some 5 million people
in surrounding areas are lacking basic necessities like
clean water, shelter, food and health care, and world governments
have said they would contribute $500 million in aid to quake-tsunami
disaster victims.
It
Could Happen in the U.S.A.
Tsunamis,
which are actually huge tidal waves caused by earthquakes
beneath the seafloor (typically they must occur at a magnitude
greater than 6.5 on the Richter scale—the one that occurred
in Asia was a 9), could happen here in the United States.
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In
fact, according to George Maul, a Florida Tech oceanographer,
when asked if a tsunami could hit the United States, he
replied, ”Absolutely. It happened in the past and they will
happen again in the future."
The
West Coast
The
West Coast is most at risk and experts say geological circumstances
similar to those in southern Asia exist near the Pacific
Northwest Coast. A rupture along the 680-mile fault known
as the Cascadia subduction zone, which is located uncomfortably
close to the West Coast (just 50 miles offshore), could
lead to a tsunami that could hit Northern California, Washington,
Oregon and British Columbia in 30 minutes or less.
Geologist
Brian Atwater of the U.S. Geological Survey put it quite
simply. "People need to know it could happen," he said.
In
fact, in 1700 a giant tsunami did hit the West Coast after
an 8.0 or greater earthquake hit the subjection zone. Sand
deposits and other evidence of severe flooding indicate
that the huge wave hit Oregon, Washington and British Columbia
with devastating consequences.
As
if that’s not unsettling enough, back in 2000 a scientist
on one news report said that they were expecting an earthquake
along the fault line sometime in the “near future.”
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Giant tsunamis have hit the
United States in the past and
researchers say they will hit again
in the future. The Pacific Coast is
most at risk, but the Atlantic
Coast, Caribbean, Hawaii and
Alaska are all at risk, as well.
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The
East Coast
There’s debate as to whether fault lines like those on the
West Coast exist along the East Coast, which is why some say
a tsunami is extremely unlikely to hit the Atlantic Coast. Others,
like George Maul, who has been writing to the government to
encourage some sort of tsunami warning system for the East Coast
(none currently exists), are not so sure.
According
to Maul, "The tsunami risk in the Pacific is significantly
higher, but about one-fourth of the earth's tsunamis occur
in the Atlantic Ocean. Most people aren't aware of that."
Computer
models do show that the East Coast could be hit by a giant
tsunami if a large volcanic eruption and landslide occurred
in the Canary Islands, but some researchers say that is only
likely to occur once every 10,000 years. Others believe the
threat is real and should be taken more seriously, especially
considering that no warning system is in place.
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Sue
Bilek, an earthquake and tsunami expert at New Mexico Tech,
said “On the East Coast, there's no subduction zones like
that [on the West Coast], but you could get a tsunami there
from a giant landslide into the ocean."
The
Gulf Coast, Hawaii and Alaska
"There's
another [subduction] zone like that near the Caribbean,"
Bilek said, and there’s no telling when underwater movements
could occur. While the Pacific Ocean has an elaborate monitoring
system (did you know there’s a Pacific Tsunami Warning Center?)
to alert scientists when tsunamis and other shifts in water
level have occurred, the Atlantic Ocean and the Indian Ocean
have no such monitors (the Caribbean Sea has one but it
only protects U.S. regions in that area including Puerto
Rico and the U.S. Virgin Islands).
Tsunami
warning centers have also been set up in Alaska and Hawaii.
Hawaii’s biggest threat is from a tsunami that would come
across the Pacific, said Gerard Fryer, a geophysicist at
the University of Hawaii, but a tsunami could also occur
from an earthquake beneath the local Mauna Loa or Kilauea
volcanoes.
Is
Prevention Possible?
It
isn’t possible to stop a tsunami from occurring, but if
warning systems such as those in the Pacific Ocean are in
place, and provided the tsunami originates far off coast,
residents could be warned hours ahead of impact and given
plenty of time to evacuate. However, if no warning system
exists, or if the tsunami originates close to shore, there
may be no warning at all.
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If
you are in a tsunami-prone region, paying attention
to any early warning signs could mean the difference
between life and death. These are subtle but include:
- The
sea suddenly “opening up,” leaving lots of fish and
marine life behind (the water will then rush back
in a few minutes later)
- Signs
put up instructing people how to get to higher ground
in the event of an earthquake (Puerto Rico uses these,
for instance)
- Bullhorns,
alarms or other sirens sounding on beaches—this means
you should immediately get off the beach (this is one
reason why Hawaii has bullhorns on beaches)
- Always
take warnings seriously and act quickly, don’t delay
or try to “watch the storm”
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Tsunamis can hit with no warning
at all. When visiting coastal
regions, pay attention to signs
like these that instruct you what
to do in case of an emergency.
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And
in the event you find yourself on the ground near a coast
when an earthquake hits:
- Get
to higher ground immediately, even if you don’t think
you’re in danger (tsunamis can appear within minutes)
- Travel
on foot, not by car or bus
- If
higher ground isn’t around, move inland as far, and as
quickly, as possible
- Once
inland, don’t go back to the coast (waves that are even
larger than the first can occur later)
- Wait
for an “all clear” signal by radio, TV or other communication
device
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