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9.0 Earthquake strikes Japan


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What an image from the USGS.

Ahh...this explains alot.

I'm hearing from the news that NE Japan is the epicenter and I'm thinking to myself; well, if that is the epicenter, then how the heck are there tsunami waves hitting Japan since any rise/fall in ocean floor level would cause the waves to propagate outward from the island.

And with that...now I see that the quakes are actually offshore. Turns out, their definition of epicenter is where the distruction is worst.

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Perhaps this has been discussed earlier in the thread but I was under the impression that you need anything over 8.0 to even have a chance at generating a significant tsunami.

Generallly it's considered that a 7.0 is sufficient to cause local tsunamis. This has certainly been a lesson hard learned in areas such as New Guinea, Indonesia, and the Caribbean Islands. It was a 7.6 earthquake in 1976 that generated a tsunami that killed 5000 in Mindanao in the Philippines.

Steve

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Generallly it's considered that a 7.0 is sufficient to cause local tsunamis. This has certainly been a lesson hard learned in areas such as New Guinea, Indonesia, and the Caribbean Islands. It was a 7.6 earthquake in 1976 that generated a tsunami that killed 5000 in Mindanao in the Philippines.

Steve

Ya really the depth of the quake and the amount of displacement in the crust along the seabed is what matters. The numbers show the potential but anything 6.5 or so and larger has the potential for a major tsunami. Really just depends on if it is shallow or a deep quake, and plate convergence type, and amount of displaced earth to generate the upward force to initiate the tsunami. 8.0 is sort of a crude estimate but is fairly accurate across the globe for the various types of quakes and plate dynamics.

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Ahh...this explains alot.

I'm hearing from the news that NE Japan is the epicenter and I'm thinking to myself; well, if that is the epicenter, then how the heck are there tsunami waves hitting Japan since any rise/fall in ocean floor level would cause the waves to propagate outward from the island.

And with that...now I see that the quakes are actually offshore. Turns out, their definition of epicenter is where the distruction is worst.

How did you not know the quake was off-shore? Every single map on TV/Internet shows the epicenter in the ocean.

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How did you not know the quake was off-shore? Every single map on TV/Internet shows the epicenter in the ocean.

If you followed from the get go, reports had the quake at about 125-130 miles off shore of the japan coast or roughly 200 something miles northeast of Tokyo. Everything I initially saw was the the quake epicenter was offshore.

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I was looking at video on weather.com showing the damage in HI from the "failnami" as the local talking heads on O'ahu were calling it. Elsewhere on Maui and the Big Island it was different-at least one house was shown floating out to sea with others knocked off foundations and cars in piles. At least one couple barely escaped with their lives when their car was swept away by the water. It would definitely appear that the warnings in Hawai'i were justified. BTW, one thing I would like to add-watching video of a strong earthquake is absolutely NOTHING like being in one. I'm sure that Josh would agree that if you get caught in a damaging or destructive earthquake that it you later say you weren't scared that you are either a liar or a fool.

Steve

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I was looking at video on weather.com showing the damage in HI from the "failnami" as the local talking heads on O'ahu were calling it. Elsewhere on Maui and the Big Island it was different-at least one house was shown floating out to sea with others knocked off foundations and cars in piles. At least one couple barely escaped with their lives when their car was swept away by the water. It would definitely appear that the warnings in Hawai'i were justified.

Wouldn't you expect that Kauai would take the brunt of the head wave and that the other islands would be somewhat shielded? I have no idea how things went down but depending on how the wave reacted to the islands I could see how it could amplify or dampen past the first island but still..... kind of a joke people are calling it a failnami, it's these same people that'll talk down the next wave and it'll be much worse that expected as history has shown us. Big tsunami's aren't all that uncommon there.

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BTW, one thing I would like to add-watching video of a strong earthquake is absolutely NOTHING like being in one. I'm sure that Josh would agree that if you get caught in a damaging or destructive earthquake that it you later say you weren't scared that you are either a liar or a fool.

Steve

Yep-- totally.

Video falls short conveying any natural disaster, but the disconnect is biggest with earthquakes. Video just doesn't capture it, because so much of it is what you feel-- the motion and the energy. It is very strange and scary.

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Does anyone want to chip in some money to send the Westboro Baptist church folks over to Japan to stand on top of the containment buildings holding signs that say "God Hates the Japanese"?

laugh.gif

thumbsupsmileyanim.gif I think that is the one of the best ideas I have heard lately! Kudos!

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basically what I mean is Oahu would basically be the most protected of the islands based on the trajectory of the tsunami wave I would think they would find themselves lucky that this didn't come from AK that would have rocked them.

Actually Maui and the Big Island on the Kona coast were hardest hit. In 1946 the tsunami came from AK and though O'ahu was hit hard it was Hilo that took it in the shorts with a 56 foot Harbor Wave.

Steve

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Actually Maui and the Big Island on the Kona coast were hardest hit. In 1946 the tsunami came from AK and though O'ahu was hit hard it was Hilo that took it in the shorts with a 56 foot Harbor Wave.

Steve

Thanks for the clarification, I was just going by layout of the islands. These tsunamis are tough to figure out with the ocean interaction, hard to believe people think that from what happened in japan that the warnings were unwarranted.

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It's shocking to see a disaster in a modern, industrialized nation which is going to completely dwarf Katrina.

As bad as Katrina was, the aerial extent of the extreme devastation was confined to a relatively small area-- stretching along the coast from E LA to W MS. It was large enough-- I'm not minimizing it-- but the scale of the tsunami damage on the NE Honshu coast is just tremendous. It looks like whole cities have just been swept clean away. It's really hard to get one's head around it. And now there is this nuclear element. I think that when all is accounted for, this may end up being one of the great "First World" disasters of the last century.

Before people jump down my throat, I'm talking specifically about disasters in the modern, industrial world because I want to compare apples to apples. Sadly, in the developing world, catastrophes (and human suffering) seem to happen on a much grander scale-- for example, the 2004 tsunamis, Cyclone Nargis, the Tangshan quake of 1976, the Bhola cyclone of 1970, etc. So, probably even the Honshu earthquake/tsunami/nuclear accident won't compare to some of these developing-world catastrophes. But for a "First World" incident, this is going to be way up there on the list.

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It's shocking to see a disaster in a modern, industrialized nation which is going to completely dwarf Katrina.

As bad as Katrina was, the aerial extent of the extreme devastation was confined to a relatively small area-- stretching along the coast from E LA to W MS. It was large enough-- I'm not minimizing it-- but the scale of the tsunami damage on the NE Honshu coast is just tremendous. It looks like whole cities have just been swept clean away. It's really hard to get one's head around it. And now there is this nuclear element. I think that when all is accounted for, this may end up being one of the great "First World" disasters of the last century.

Before people jump down my throat, I'm talking specifically about disasters in the modern, industrial world because I want to compare apples to apples. Sadly, in the developing world, catastrophes (and human suffering) seem to happen on a much grander scale-- for example, the 2004 tsunamis, Cyclone Nargis, the Tangshan quake of 1976, the Bhola cyclone of 1970, etc. So, probably even the Honshu earthquake/tsunami/nuclear accident won't compare to some of these developing-world catastrophes. But for a "First World" incident, this is going to be way up there on the list.

I agree fully with this, the magnitude of loss of life/destruction upon the infrastructure of a highly advanced country is astounding here.

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basically what I mean is Oahu would basically be the most protected of the islands based on the trajectory of the tsunami wave I would think they would find themselves lucky that this didn't come from AK that would have rocked them.

You also have to watch out for wave refraction around the islands. Sometimes the largest waves can occur on the opposite side than you would expect.

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New video running from Miyagi(sp?) on Today Show. It shows why the death toll is going to be horriffic. On one side of the shot you see an absolute wall of water descending on the city. On the other side of shot, you see cars driving normally along a roadway, unawares of what is about to sweep over them. Multiply that times thousands of situations and the death toll when the news finally gets around to talking about it honestly is going to be hard to comprehend.

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It's shocking to see a disaster in a modern, industrialized nation which is going to completely dwarf Katrina.

As bad as Katrina was, the aerial extent of the extreme devastation was confined to a relatively small area-- stretching along the coast from E LA to W MS. It was large enough-- I'm not minimizing it-- but the scale of the tsunami damage on the NE Honshu coast is just tremendous. It looks like whole cities have just been swept clean away. It's really hard to get one's head around it. And now there is this nuclear element. I think that when all is accounted for, this may end up being one of the great "First World" disasters of the last century.

Before people jump down my throat, I'm talking specifically about disasters in the modern, industrial world because I want to compare apples to apples. Sadly, in the developing world, catastrophes (and human suffering) seem to happen on a much grander scale-- for example, the 2004 tsunamis, Cyclone Nargis, the Tangshan quake of 1976, the Bhola cyclone of 1970, etc. So, probably even the Honshu earthquake/tsunami/nuclear accident won't compare to some of these developing-world catastrophes. But for a "First World" incident, this is going to be way up there on the list.

at least the NE coast of Japan isn;t that populated.....could you imagine that wave hitting tokoyo bay if it was more south

before afer after pics..scroll across the pic

http://www.abc.net.a...beforeafter.htm

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Man, the Today Show is bringing the stupid this morning. Jenna whatever her last name is just bumped out of the first hard news segment with this tease:

"Is there anything that can be done to prevent tsunamis?"

I am going to stick around and see where this goes. The mind boggles. I am thinking, what, REALLY high REALLY reinforced walls? Trying not to giggle over the siliness of that particular tease...

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What about the New Madrid fault in the S.E. US. What is the magnitude potential there?

The latest careful scholarship has revised down the magnitudes of the 1811-1812 quakes; they were around M7.

http://showme.net/~fkeller/quake/lib/smaller.htm

Also, rather controversially, some have found there's no strain accumulation at all in the area.

Places like Salt Lake City, Reno, Albuquerque, etc. are far more likely to have the "devastating lower 48 quake outside of the west coast."

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