Major earthquake hits Japan followed by tsunami

[kristie]

wow!!

http://www.foxnews.com/world/2011/03/11/massive-7-magnitude-earthquake-strikes-japan/

 

[windward]

Tsunami warning in Hawaii.

 

[TheDallasDon]

A 8.9 WOW!!! followed by a tsunami thats crazy I'll pray for them

 

[kristie]

Tsunami warning in Hawaii.

heard about that. the warning signals went off in honolulu, i think.

 

[kristie]

A 8.9 WOW!!! followed by a tsunami thats crazy I'll pray for them

so will i.

 

[Warick]

That is insane.. A friend of mine called me said he watched video of the tsunami coming in, and taking out an airport, washing away planes, everything. 8.9 is crazy. Warnings issued all over the place including the West Coast. I'm sure Hawaii will be hit pretty hard.

RIP to the victims..

 

[SaltwaterServr]

That is insane.. A friend of mine called me said he watched video of the tsunami coming in, and taking out an airport, washing away planes, everything. 8.9 is crazy. Warnings issued all over the place including the West Coast. I'm sure Hawaii will be hit pretty hard.

RIP to the victims..

Watching it on Fox and MSNBC right now. The burning piles of flotsam rolling inland, wow.

Tsunami warnings for most of the US west coast now.

 

[CliffnDallas]

It should hit Hawaii around 3am local time. The whole of the Pacific in under threat.

 

[kristie]

It should hit Hawaii around 3am local time. The whole of the Pacific in under threat.

seriously scary.

 

[SaltwaterServr]

Google's home page has the warning up when you go to it.

Phillippines expected to get hit anytime between now and the next two hours.

Hawaii should expect it about four hours from now.

Wow, biggest one to hit Japan in 140 years.

 

[CliffnDallas]

seriously scary.

If a 8.9 hit LA, I could finally open that glass bottom boat Hollywood tour business.

 

[SaltwaterServr]

If a 8.9 hit LA, I could finally open that glass bottom boat Hollywood tour business.

Wow, Red Cross saying the wave was higher than some populated Pacific Islands.

 

[SaltwaterServr]

Add on: This quake released about 900 times the amount of energy as the 89 San Francisco Bay area quake.

 

[CliffnDallas]

Wow, Red Cross saying the wave was higher than some populated Pacific Islands.

The further the pressure wave travels the higher it will be/more water mass it will have when it reaches land. Right?

 

[SaltwaterServr]

The further the pressure wave travels the higher it will be/more water mass it will have when it reaches land. Right?

No. The water itself in the middle of the ocean never moves, it actually goes through a series of small vortices and comes back to the same place it started at. The entire vortice might be only a few centimeters in diameter.

The thing is that the wavelength, the actual distance between first and second crest, and wave height are unnoticeable at open sea. As that energy wave nears the shore, it compacts to a degree and the ocean floor begins to "push" up the water as the energy moves forward. That's the critical issue, the water only moves up and inland when the energy wave begins to interact with the ocean floor.

Here's a pretty good animation showing what is referred to as "stacking" when the waves come onshore.

http://www.pep.bc.ca/tsunamis/causes_2.htm

On the bottom left of the map, click the next button 3 times until the wave starts to travel from left to right on the screen. It'll show the waves being not noticeable at all offshore, although divers in the water itself will fell the energy wave pass through their bodies. The next animation after that shows the stacking effect that causes the majority of shoreline and inshore damage.

The secondary issue of flooding can be seen by then hitting next again once that animation completes, but it's really just showing the breadth one of these waves can have and the fact that there are usually several of them.

Of note, was tsunami waves come close to shore, the sea will retreat as the energy waves stacks offshore, causing water to run back towards it. Some of the Indonesian tsunami footage showed fairly extensive beaches with no water on them for hundreds of meters offshore.

 

[CliffnDallas]

No. The water itself in the middle of the ocean never moves, it actually goes through a series of small vortices and comes back to the same place it started at. The entire vortice might be only a few centimeters in diameter.

The thing is that the wavelength, the actual distance between first and second crest, and wave height are unnoticeable at open sea. As that energy wave nears the shore, it compacts to a degree and the ocean floor begins to "push" up the water as the energy moves forward. That's the critical issue, the water only moves up and inland when the energy wave begins to interact with the ocean floor.

Here's a pretty good animation showing what is referred to as "stacking" when the waves come onshore.

http://www.pep.bc.ca/tsunamis/causes_2.htm

On the bottom left of the map, click the next button 3 times until the wave starts to travel from left to right on the screen. It'll show the waves being not noticeable at all offshore, although divers in the water itself will fell the energy wave pass through their bodies. The next animation after that shows the stacking effect that causes the majority of shoreline and inshore damage.

The secondary issue of flooding can be seen by then hitting next again once that animation completes, but it's really just showing the breadth one of these waves can have and the fact that there are usually several of them.

Of note, was tsunami waves come close to shore, the sea will retreat as the energy waves stacks offshore, causing water to run back towards it. Some of the Indonesian tsunami footage showed fairly extensive beaches with no water on them for hundreds of meters offshore.

So the wave energy/mass when it nears shore, does not depend on the ammount of water displaced by the event?

 

[SaltwaterServr]

So the wave energy/mass when it nears shore, does not depend on the ammount of water displaced by the event?

Bass ackwards. But also right on the money. The amount of water displaced has to be displaced a certain way, which means there are degrees of efficiencies of conversion from water displacement to wave formation.

The energy released from the quake itself that gets converted to wave energy will determine how much water gets displaced by the event. The conversion of quake energy released to wave energy traveling in the water column is dependent on depth of the quake, type of rock structure, as well as type of the quake. IIRC, depth is second most important behind type, and rock structure really only comes into play in coastal regions where tsunami formation isn't that probable. The San Francisco quake was so damaging because a lot of San Fran sits on unstable soil. Its like when you "pat" sand on the shoreline to the point it liquifies. Same thing happened in San Francisco. The waves of that particular quake caused "liquefaction" of the subsoil layers.

Type:

A strike/slip fault earthquake in which the ocean floor slides laterally usually doesn't (usually being the operative word) have the same effect as a subduction fault where the ocean floor actually jumps upwards. IIRC, the Indonesia quake epicenter caused the ocean floor to jump both upwards by about 6-8 meters and slide laterally about the same amount. The jump of the ocean floor is what caused that bad boy to do the damage it actually did.

Think about having two bricks underwater in a swimming pool. Move them past each pretty quick about 3 feet under water, and not much happens. Now take one of those bricks and push it three foot to the surface, from three foot down. That produces a lot of displacement energy upwards, which is a more efficient quake to wave motion conversion process.

Now strike slip lateral quakes can be devastating as well, but it really matters how the fault is aligned to nearby land masses.

EDIT: Calling it "wave energy/mass" isn't a good way to describe it. It's simply wave energy, there is no mass. There are only two water masses that move: directly above the quake, and it really doesn't go anywhere per se, and the water on the coastal areas where the underwater wave height begins to interact with the ocean floor.

Second edit: There are two uses of the word "wave" that will get confusing. "Wave" energy isn't a surface "wave" like you're thinking of. Its the sinusoidal movement of energy, that travels in waves. When it gets close to shore, do you ever begin to see the actual surface "wave" that surfers ride, but that is actually the wave energy pushing the water up. The energy wave propagated at the event epicenter offshore shows no surface wave, until it nears shore. I read this again, and I can see where that could be confusing to some.

 

[kristie]

i'm just hoping that the wave doesn't hit alaska because i have family there(father, stepmother & younger brother).ray:

 

[kristie]

4.5 earthquake hit hawaii!!!!

just heard it right now on fox news.

 

[SaltwaterServr]

i'm just hoping that the wave doesn't hit alaska because i have family there(father, stepmother & younger brother).ray:

I was just running through a few sites, USGS, and such, and Alaska might get a few inches to a few feet. The angle of the actual quake is shooting almost directly across the Pacific. A wave front moves in a semi-circle, which we've all seen when a rock is tossed into water. Concentric rings radiate out from the impact zone. In this case, because of the type and direction of the quakes and aftershocks, the wave front is pretty concentrated energy within a narrow range, with Baja Mexico and Alaska getting pretty weak effects.