Dangerous tsunami threat off U.S.
West Coast
By Los Angeles Times, adapted by Newsela staff on 03.24.14
Word Count 834
Surfer Lee Johnson emerges from the water at San Onofre State Beach, Calif., with the twin domes from the
San Onofre Nuclear Generating Station in the distance. Officials have said the plant can sustain a 7.0
quake but not the 9.0 that struck Japan in 2011. Photo: Mark Boster/Los Angeles Times/MCT
LOS ANGELES — If a 9.0 earthquake were to strike in the ocean off California, it
would have a catastrophic effect for much of North America’s West Coast.
While earthquakes on land can cause massive damage, an earthquake in the
ocean can trigger a tsunami, a huge wave that rushes inland, destroying
everything in its path.
A giant tsunami along the West Coast would wash away coastal towns, destroy
U.S. Highway 101 and cause $70 billion in damage. More than 100 bridges
would be lost, power lines toppled and coastal towns isolated. Residents would
have as few as 15 minutes’ notice to flee to higher ground, and as many as
10,000 would die.
Last year, scientists studied the possible effects of a huge earthquake coming
from the Cascadia fault system, which sits 700 miles off the coast of northern
California. They predicted massive damage.
"The Big One"
Many scientists have long expected that the famous San Andreas fault will
produce “The Big One,” a massive earthquake that could rock the West Coast
at any time. But recently, scientists have realized that the Cascadia fault is far
more dangerous than they thought.
The Cascadia fault is made up of three tectonic plates that are pushing against
each other. Cascadia produced the two largest earthquakes in California in the
last decade: a 6.8 quake on Sunday and a 7.2 quake in 2005. The area has
produced six quakes of magnitude 7.0 or greater in the last 100 years, the
California Geological Survey said.
Officials in Northern California, Oregon and Washington are beginning to
address the dangers.
Many scientists have begun to focus on the dangers of an earthquake and
tsunami. In 2011, a 9.0 earthquake created a huge tsunami in Japan that swept
through coastal areas.
That tsunami took residents by surprise. It killed more than 10,000 people and
left more than 300,000 homeless. It also damaged a nuclear power plant,
causing a meltdown and spreading dangerous radiation in the area.
Researchers from the U.S. National Oceanic and Atmospheric Administration
(NOAA) hope that new tsunami detectors off Oregon’s coast could provide early
warnings of a wave, and also tell scientists its size.
Predicting a tsunami’s strength is crucial to saving lives. During the 2011 Japan
tsunami, scientists underestimated its size and did not anticipate the massive
damage it would do.
“You want to have this information as accurate as possible.” said Vasily Titov,
director of NOAA’s Center for Tsunami Research.
Evacuating Vertically
Installing tsunami sensors on the deep ocean floor would provide better
information on the tsunami’s size in as little as five minutes. It now takes about
half an hour.
Titov said two underwater test sensors off the Oregon coast seemed to perform
well in Sunday’s earthquake, though the quake did not produce a tsunami.
To escape a tsunami people must flee to high ground — a hill or mountain for
example. But in flat places, there is nowhere to go. Safety officials must get
creative.
One option is buildings that are designed as “vertical evacuation centers.” In
case of a tsunami, people could go to these buildings and take shelter on the
roof. One building at an elementary school in Washington state will be able to
protect 1,000 people with a high wall.
“We have no natural high ground,” said Ocosta School District Superintendent
Paula Akerlund. “So we have to evacuate vertically.”
Officials have also discussed building about 50 “tsunami safe havens,” such as
artificial hills that could hold as many as 800 people.
After the 2011 Japan tsunami, officials began to prepare for a major quake on
the Cascadia fault.
And in the back of their minds is Hurricane Katrina, which devastated New
Orleans in 2005. The huge hurricane completely overwhelmed the city as the
levees gave way. A Cascadia earthquake and tsunami could similarly
overwhelm the West Coast, said Paul Whitmore, director of the National Tsunami
Warning Center in Alaska.
Cascadia Fault More Powerful
Scientists had believed that the Cascadia fault zone could only produce a 7.5
earthquake. But they now believe that it could create an enormous 9.0 quake —
the same size as the one that rocked Japan.
The Cascadia fault is powerful for two reasons. First, it is extremely long.
Second, it is an area where two huge tectonic plates are being pushed under
the gigantic North American plate. The smaller plates push under little by little,
dragging the North American plate down with them.
But the North American plate is old and strong, and it won’t be pulled down
forever.
Once every couple hundred years, the North American plate snaps back
upward like a rubber band, creating a powerful earthquake.
On March 16, a small quake caused by the Cascadia fault erupted 50 miles off
the coast, causing moderate shaking. No injuries or damages were reported.
The West Coast was spared this time, but scientists still wonder when “The Big
One” will hit.
“It could be today. It could be 100 years from now,” U.S. Geological Survey
seismologist David Oppenheimer said.
Quiz
1
2
3
What are two MAIN ideas in the section "The Big One"?
(A)
Scientists now think that the Cascadia fault, not the San Andreas
fault, will be the source of the next big earthquake; the earthquake
could result in a tsunami similar to a tsunami in Japan in 2011.
(B)
Earthquakes and tsunamis often occur together depending on the
geography of a place; scientists are working hard to create
protocols to predict and prepare for earthquakes and tsunamis.
(C)
The San Andreas fault is an extremely dangerous fault that is
scheduled to erupt in the next few years; many people are moving
closer to the Cascadia fault to avoid any earthquake-related
destruction.
(D)
Japanese scientists and American scientists are working together
to better understand how earthquakes cause tsunamis; so far, their
collaborations have allowed them to predict the eruption of the
Cascadia fault.
How does the title "Evacuating Vertically" serve as a summary of that section?
(A)
The title conveys the section's emphasis on different ways of
getting people underground to stay safe during a tsunami.
(B)
The title conveys the section's emphasis on different ways of
getting people onto higher ground to stay safe during a tsunami.
(C)
The title conveys the section's emphasis on how much taller the
Cascadia fault is than the San Andreas fault.
(D)
The title conveys the section's emphasis on how how much taller a
tsunami is than an average wave.
According to the article, why might officials be thinking about Hurricane Katrina
when preparing for an earthquake-induced tsunami?
(A)
The hurricane was caused by an earthquake that occurred in the
Pacific Ocean similar to how an earthquake could cause a major
tsunami in California.
(B)
The hurricane that affected New Orleans was actually a tsunami
that was caused by an earthquake that occurred in Japan.
(C)
The hurricane completely overwhelmed New Orleans with water
similar to how a tsunami could overwhelm the West Coast with a
flood.
(D)
The hurricane was caused by earthquakes in California. The force
of California earthquakes can spread across states.
4
According to the article, why have researchers decided to install tsunami detectors
on the ocean floor?
(A)
To provide early warnings of a tsunami to marine life and to collect
information about earthquake size
(B)
To collect information about earthquake size and to predict how
much flooding will occur on land
(C)
To warn the Japanese of any future earthquakes or tsunamis
(D)
To provide early warnings of a tsunami and to collect information
about tsunami size
Answer Key
1
2
What are two MAIN ideas in the section "The Big One"?
(A)
Scientists now think that the Cascadia fault, not the San
Andreas fault, will be the source of the next big earthquake; the
earthquake could result in a tsunami similar to a tsunami in
Japan in 2011.
(B)
Earthquakes and tsunamis often occur together depending on the
geography of a place; scientists are working hard to create
protocols to predict and prepare for earthquakes and tsunamis.
(C)
The San Andreas fault is an extremely dangerous fault that is
scheduled to erupt in the next few years; many people are moving
closer to the Cascadia fault to avoid any earthquake-related
destruction.
(D)
Japanese scientists and American scientists are working together
to better understand how earthquakes cause tsunamis; so far, their
collaborations have allowed them to predict the eruption of the
Cascadia fault.
How does the title "Evacuating Vertically" serve as a summary of that section?
(A)
The title conveys the section's emphasis on different ways of
getting people underground to stay safe during a tsunami.
(B)
The title conveys the section's emphasis on different ways of
getting people onto higher ground to stay safe during a
tsunami.
(C)
The title conveys the section's emphasis on how much taller the
Cascadia fault is than the San Andreas fault.
(D)
The title conveys the section's emphasis on how how much taller a
tsunami is than an average wave.
3
4
According to the article, why might officials be thinking about Hurricane Katrina
when preparing for an earthquake-induced tsunami?
(A)
The hurricane was caused by an earthquake that occurred in the
Pacific Ocean similar to how an earthquake could cause a major
tsunami in California.
(B)
The hurricane that affected New Orleans was actually a tsunami
that was caused by an earthquake that occurred in Japan.
(C)
The hurricane completely overwhelmed New Orleans with
water similar to how a tsunami could overwhelm the West
Coast with a flood.
(D)
The hurricane was caused by earthquakes in California. The force
of California earthquakes can spread across states.
According to the article, why have researchers decided to install tsunami detectors
on the ocean floor?
(A)
To provide early warnings of a tsunami to marine life and to collect
information about earthquake size
(B)
To collect information about earthquake size and to predict how
much flooding will occur on land
(C)
To warn the Japanese of any future earthquakes or tsunamis
(D)
To provide early warnings of a tsunami and to collect
information about tsunami size