Geology and Earth ScienceMajor Tsunami Threat in the U.S.
Cheryl Kalman
Ever since the South-East Asian tsunami happened a lot of countries have been asking “can it happen here?” Kevin Furlong a professor of geosciences at Penn State says “Unfortunately the answer is yes – big time.” Undersea landslides caused by small earthquakes off the coast of California can cause isolated tsunamis but, that is not the real threat to the U.S. The threat lies in an area known as the Cascadia Subduction Zone; it is a 600 mile wide fault off the Pacific coast that stretches from Northern California to central Vancouver Island.
Evidence suggests that 300 years ago the Cascadia Subduction Zone ruptured and caused a tsunami equal to the one that devastated South-East Asia. Researchers have found deposits of sea floor sediment in Oregon, Washington and British Colombia, at areas too far inland to be reached by normal tidal activity. When a tsunami occurs it picks up large amounts of sand and deposits it however far inland the water reaches. Another strong piece of evidence is tree ring dating shows that the northwest forests were killed by cataclysmic flooding around the same time. Native American legends still survive in many tribes that also depict this horrifying tsunami. However, the strongest piece of evidence came from the Japanese who have been recording tsunamis for 1,300 years. Japan got hit by a tsunami without warning on January 26, 1700. There was no earthquake felt at all there. Scientists recently determined that a 9.0 magnitude earthquake struck along the Cascadia Subduction Zone in 1700, creating a tsunami that hit the Pacific Northwest while also sending 16-foot-high waves slamming into Japan 10 to 20 hours later.
The geologic record has revealed that this type of rupture happens once every 300-500 years and that means we are due for another one. Experts predict you will only have 15-30 minutes to evacuate coastal towns because the plate boundary is only 100 kilometers off shore.
The 1964 tsunami that hit Alaska prompted the government to establish the federal tsunami monitoring system. This is run by the National Oceanic and Atmospheric Administration. Although the U.S. has set up advanced siren systems along the coasts that are more susceptible to tsunamis; with such a short evacuation time experts are not sure how much this will help, all they know for sure is when this Subduction zone ruptures again the devastation will be great.
Reference:
http://live.psu.edu/story/14499
4 Comments:
After reading this posting on tsunamis I started to wonder if the scientific community has made any progress in predicting these horrific natural disasters. The tsunami that reeked havoc on coastal communities all around the Indian ocean on the 26th of December 2004 brought to light an important fact, as populations are booming in coastal areas around the world, more and more people will be exposed to this threat like that effected millions of people that December in 2004 among the millions 225,000 lost there lives.
So the question is the world better prepared? This Tsunami was the best documented in history. So at least some good came out of all this devastation, being so well documented it opened a unique opportunity for scientists to help make the world better prepared to deal with tsunamis in the future.
Unlike the Pacific Ocean that has a tsunami warning system the Indian Ocean has no such system. This made the people of this region very vulnerable and we all watch what happened on television. Since then the international community coordinated by UNESCO’S (United Nations Educational, Scientific and Cultural Organization.) Intergovernmental Oceanographic Commission, are trying to correct this oversight.
What are needed are three components 1. A seismic network to locate large earthquakes,
2. At least five tsunameters capable of detecting tsunami waves as they travel across the open ocean. Thirteen of these meters would detect a tsunami in less than thirty minutes.
3. A real time network of tide gauges near the shores.
As of January 2006 some advances were made. Two seismic networks are now reporting automatically to the national earthquake centers in Indonesia and Malaysia. Four tide gauges were upgraded for tsunami monitoring twenty others are due to come online this year. Unfortunately the necessary numbers of tsunameters if any are in place.
Part of the problem is political and economical. The world need to come together on this, but unfortunately the good will that is present immediately after these tragedies is usually fleeting.
Even though early warning systems make a big difference in the outcome nothing can take the place of education, and people who live and visit tsunami prone areas need to educate themselves regarding early warning signs.
Reference for this response. Geist, Titov, and Synolakis. ( January 2006 ). Tsunami: Wave of Change. Scientific America, 294, 42-49.Kandel,
It’s pretty scary that a tsunami can possibly hit the United States again some time in the future. But the good thing is that they are talking about a Subduction zone in the Pacific Ocean that if it erupts it will take out the west coast of the United States. It will be sad for the people that we will loss but be happy that it didn’t hit the east coast. Meanwhile they are trying to set up machines that they can monitor it because they will only have 30min to clear out of the coast and if it is going to be worst then the one that’s hit South-East Asia they need all the times they can get. But we live in the east coast; I wonder that if there is subduction zone in the east how bad will it get. I know that the west is known for having earth quacks and all but I am not concern about the west when I live in the east. There are subduction zones in the Atlantic Ocean that could give us a tidal wave on the east coast. And if there is one to hit us I think that long island would be wiped out along with New York City and a lot of the east coast would be good to. Hopefully this is one of those things that you don’t have to worry about because it wont erupt while we are a live so we can think how pretty everything and nothing can harm us in our little world.
But the tsunami that hit South-East Asia was really bad I remember looking at the tv and seeing the wave coming to them and then wiping everything out like it was nothing there. It most of been a really scary thing to see before you die. If I was in a good position in my life I would do anything to help those people get back on there feet. But I do wish them all good luck and wish that it would never happen to them again.
They should start educating some of these countries that could be hit my one of these things so we don’t have to worry about them doing the right thing if it does hit in our life time.
Do you really think that a 30 minute warning is enough? With all the technology that we have today you would think we could come up with something better? Can we rate the time that the plates move towards each other and see when an earthquake occurs?. Is it when they move fast? If i was living on the west coast i would like somethig better then half hour to run ad save my life and everyone is going to try and leave and have more dealths occur then could possible have. If we have been gathering data for over 1000 years don't you think we should have something better then this? What was occuring right before the earthquake happened? was it repitive everytime after that? If we see these things that we can better predict then when it does and have 30 minutes to run. If we have so much knowledge but i just don't think were using it in the right mind. We can fly in air, go to the moon and mars but can't figure out what makes these devestating accidents happen? I want them to go over there work and look for patterns , weather conditions, something that matches to other times when this has occured
I am beginning to fear the location of my home as I sit here reflecting on the previous natural disaster that killed many in Indonesia. If a tsunami were to rush from the Atlantic ocean on to the eastern coast of North America, I would be washed away immediately, especially because I live on an island. The only thing surrounding an island is water, the obvious. : ) Long Islanders wouldn’t stand a chance in trying to escape. The only way to escape this island is through New York City into New Jersey or up state New York. Squeezing the entire Long Island population, along with the population of the five boroughs, onto the mainland would be chaotic. There would never be enough time for any New Yorker to escape in hope for shelter from the seismic sea wave. Along with the wave velocity, the intrusion into New York City would cause massive destruction. If the wave’s capacity and velocity are strong enough, buildings will shatter, millions of people will die, and the aftermath of reconstruction would take years, maybe decades, to repair.
What frightens me about a tsunami is that they are caused by earthquakes. Earthquakes occur all the time! Their frequent intensities may not be life threatening, but they occur more often than we assume. It only takes one earthquake to ignite a tsunami. When a tsunami hits, its effects are devastating and quite frankly, frightening. Since I am terrified of bugs, I can only imagine myself being washed away by the ocean’s salt water infested with hundreds of disgusting species, like fish. Yes, fish, or any marine dwelling species!
While I am putting the damages caused by a tsunami into perspective, it seems as if they are one of the most devastating natural disasters to occur. Not only is a tsunami caused by an intense earthquake, but its aftermath results in flooding. What was once land is now water. Knowing that North America is due for a tsunami scares the living day lights out of me! I could be here one day and then the next I’m washed away, floating amongst disgusting species or as I like to call them, creatures. :)
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