What is the proper response to a tsunani?

[Peter]

Falling overboard

But, Ed, the chances are pretty good that if you fall O/B, the boat's on some sort of self steering. In order to fall in, you'd need to at least be standing up near the gunwale, or more likely doing something outside the cockpit. In either case, unless it's only for a second or two, your're away from the helm, and the boat's rounding up and out of control, as you said. Unless it's steering itself, either thru perfect balancing of the helm, tieing down the tiller, or an autopilot or windvane. So most likely that if you fell O/B, you can't expect a round up.If we're going to continue to discuss falling overboard while singlehanding, we might want to start another thread...

 

[Peter]

Falling overboard

But, Ed, the chances are pretty good that if you fall O/B, the boat's on some sort of self steering. In order to fall in, you'd need to at least be standing up near the gunwale, or more likely doing something outside the cockpit. In either case, unless it's only for a second or two, your're away from the helm, and the boat's rounding up and out of control, as you said. Unless it's steering itself, either thru perfect balancing of the helm, tieing down the tiller, or an autopilot or windvane. So most likely that if you fell O/B, you can't expect a round up.If we're going to continue to discuss falling overboard while singlehanding, we might want to start another thread...

 

[Scott]

Did anybody watch TV last night?

I think it was Dateline for an hour special. These programs are so frustrating because they just do not seem to offer anything that comes close to a comprehensive explanation. They leave so many unanswered questions.They focus on the human devastation and that is very sad to see. But they barely gloss over the reason the waves hit only select areas. Then they get ridiculous when they hit the sensational angle and try to scare everybody on the eastern seaboard with the theory about the Canary Islands crashing into the sea. They find a scientist who is obvioulsy so giddy with excitement over being on TV that he will say anything, no matter how stupid it is. They use special effects film clips from fantasyland and try to convince us that "a scene like this" could be reality.Does anybody not understand that the focus of television news (or even printed news) is really entertainment? Why do they make stupid statements about our eastern cities being threatened, when they offer no explanation why Calcutta, directly in the path of the recent tsunami, was unaffected.I'm convinced that only shoreline areas that have unique topographic characteristics can be susceptible to these waves but these types of explanations simply aren't sensational enough to explain on TV or in the news.Hey Gord, I think Harry Belefonte makes more sense!

 

[Scott]

Did anybody watch TV last night?

I think it was Dateline for an hour special. These programs are so frustrating because they just do not seem to offer anything that comes close to a comprehensive explanation. They leave so many unanswered questions.They focus on the human devastation and that is very sad to see. But they barely gloss over the reason the waves hit only select areas. Then they get ridiculous when they hit the sensational angle and try to scare everybody on the eastern seaboard with the theory about the Canary Islands crashing into the sea. They find a scientist who is obvioulsy so giddy with excitement over being on TV that he will say anything, no matter how stupid it is. They use special effects film clips from fantasyland and try to convince us that "a scene like this" could be reality.Does anybody not understand that the focus of television news (or even printed news) is really entertainment? Why do they make stupid statements about our eastern cities being threatened, when they offer no explanation why Calcutta, directly in the path of the recent tsunami, was unaffected.I'm convinced that only shoreline areas that have unique topographic characteristics can be susceptible to these waves but these types of explanations simply aren't sensational enough to explain on TV or in the news.Hey Gord, I think Harry Belefonte makes more sense!

 

[Ed]

Scott: What you wrote is quite valid

Bathymetry plays an important role in wave development. Since the wave's height cannot exceed 1/2 the wave's length (or it will fall onto itself) the instant the wave senses interference from the bottom, it will start to slowdown, and gain in amplitude. Since much of the eastcoast is relatively shallow (at least to the continental shelf) a major tsumani would start to build up in height far from shore, and would likely collapse onto itself a reasonable distance from shore. Nonetheless, there might still be a 'swell' high enough to create shore damage, but it would likely be not much greater than what could be expected from a huricane's storm surge during high tide.~ Happy sails to you ~ _/) ~

 

[Ed]

Scott: What you wrote is quite valid

Bathymetry plays an important role in wave development. Since the wave's height cannot exceed 1/2 the wave's length (or it will fall onto itself) the instant the wave senses interference from the bottom, it will start to slowdown, and gain in amplitude. Since much of the eastcoast is relatively shallow (at least to the continental shelf) a major tsumani would start to build up in height far from shore, and would likely collapse onto itself a reasonable distance from shore. Nonetheless, there might still be a 'swell' high enough to create shore damage, but it would likely be not much greater than what could be expected from a huricane's storm surge during high tide.~ Happy sails to you ~ _/) ~

 

[Jim]

VIsit NOAA website for

definitive answers/discussion on what, why, how. I believe they also provide historical data on frequency, etc including highest recorded wave of 435 meters in 1958 in Alaska. Good, albeit sobering reading.

 

[Jim]

VIsit NOAA website for

definitive answers/discussion on what, why, how. I believe they also provide historical data on frequency, etc including highest recorded wave of 435 meters in 1958 in Alaska. Good, albeit sobering reading.

 

[Alan]

Canary Island breakaway

After doing some research, it turns out that island breakaways in the Atlantic are an ongoing event that will reoccur. It's not a matter of the mathematical probability, it's a certainty. The only question is WHEN!And when it does happen, what happened in Southeast Asia will seem like a minor event in comparison. Evacuating the East Coast in 7 hours is not even remotely possible. I doubt 7 days would be enough time. This event will cost tens of millions of people their lives and devistate the world community.

 

[Fred Ficarra]

Alan! let us in on your research.

I went to NOAAs web site for Tsunami info. They have all kinds of stuff,,,for the Pacific Ocean. Where did you find anything about the Canary Islands? Can you post some links?  You weren't looking a National Inquirers web site were you? Nah!

 

[Dan Jonas]

East coast

Fred,I read some of the same stuff Alan is referencing. The scientist disagree on the potential magnitude of the problem. If the land slips into the sea quickly and in one large chunk, the east coast and much of the Caribbean, parts of Africa, England, etc. are toast (300' Tsunami). There are some who argue that the evidence suggests the event will more likely occur in smaller chunks (parts of the island). In that event, the resulting Tsunami is smaller.Just type in Canary Islands Tsunami and you will probably find everything you want or don;t want to know.Dan Jonas (S/V Feije II)

 

[Alan]

Fred,There is lots of evidence

This is part of a paper from the research of Dr. George Pararas-Carayannis"The eastern section of AGFZ is an area of active tectonic interaction, capable of producing large earthquakes with variable tsunamigenic efficiencies. Although the Lisbon earthquake of 1755 was a rare and unusual combination of seismic and tsunami events, a recurrence in the future is a certainty. However, in the absence of adequate historical earthquake data, it is not possible to provide a statistical probability as to when an event similar to the Great Lisbon Earthquake and Tsunami of 1755 may reccur." Dr George Pararas-CarayannisThis earthquake in the Azores, occured on Nov 1, 1755. It desroyed the city of Lisbon, Portugal as waell as Morroco and these remarkable tsunami waves and effects were recorded and reported everywhere, on both sides of the Atlantic. Waves up to 60 feet in height hit a vast area stretching from Finland to North Africa and across the Atlantic to Martinique and Barbados causing much destruction and loss of life. Lakes as far north as Sweden were affected as well as the river Dal in Norway, 1800 miles (about 2,890 kilometers) away, which overflowed its banks.Using the postulated tsunami source parameters {300 kilometers radius (282,000 square kilometers), and about 30 meters of subsidence} Dr. Mader' numerical modeling study provided estimates of the tsunami travel time and the deep water tsunami wave amplitudes along the east coast of USA, in the Caribbean and the Gulf of Mexico. Travel time to the US east coast was about 7 hours

 

[Fred Ficarra]

Thanks Alan

The guys were talking about the continental shelf protecting the US Atlantic coast from a tsunami. Any evidence that the 1755 wave reached the US? The Caribbean doesn't have a similar shelf.

 

[Ed]

Not likely along the east coast.

The relatively shallow waters along much of the east coast will probably cause a major tsunami to break far offshore. Notice, this latest Indian Ocean tsunami didn't hit Calcutta or Bangladesh. Those areas have relatively shallow waters that extend far offshore (same as the US east coast).However, Parts of Florida, Bermuda, Maine and areas north of Maine may be at risk, as the bathymetry off their shores is steeper, with almost not shelf.I think the folks in NY have shown they can evacuate quickly if they think they must. NYC could be a ghost-town in 7 hours if it needed to be evacutated. Sure, there will be some who will likely stay behind, but I think most would be in NJ long before the wave (if it even reaches the shore) hit.~ Happy sails to you ~ _/) ~

 

[Fred Ficarra]

Alan, I've just gotta step up to bat here.

Your quoted 'good Greek doctor' is one thing, but that doesn't make it a certainty. What you phrase in succulent scientific jargon, is no more than one man's opinion, not science. And what is a postulated tsunami source parameters? Or variable tsunamigenic efficiencies? That middle word, a combination of Japanese and ??? is especially suspect. Sounds like Internet creativity. How's that for a new buzz word?

 

[Ed]

Tsunami didn't hit the US in 1755.

Back then the shoreline was considerably different from today. There were more and larger barrier islands, and the bathymetry nearshore was even shallower than today. Nonetheless, the eastern OCS is still a large and broad impediment for major tsunamis to overcome.~ Happy sails to you ~ _/) ~

 

[Alan]

Yes it did!

You can choose to ignore the facts, but that doesn't change what happened. Check out this NOAA web site and see for yourself.http://www.erh.noaa.gov/er/phi/reports/tsunami.htm

 

[Herb Parsons]

My Research Indicates

I've done some research too, and believe, I'm not quite sure mind you, but I BELIEVE that no matter what I do, no matter what mountain top I hide on, or what hole I dig, or what portective barrier I try to erect, I'm going to die someday. Me, and everyone I know.So, with that surety I guess I won't spend much time troubling myself about things I can really do nothing about. So, until it's my turn, I think I'll go sailing.

 

[Al Nash]

OPEN SEA-NO PROBLEM

I don't see an answer to your question of how to protect your boat from a tsunami. In the open ocean, you don't have to. Here is an excerpt from NOAA:"In the deep ocean, tsunami wave amplitude is usually less than 1 m (3.3 feet). The crests of tsunami waves may be more than a hundred kilometers or more away from each other. Therefore, passengers on boats at sea, far away from shore where the water is deep, will not feel nor see the tsunami waves as they pass by underneath at high speeds. The tsunami may be perceived as nothing more than a gentle rise and fall of the sea surface. The Great Sanriku tsunami, which struck Honshu, Japan, on June 15, 1896, was completely undetected by fishermen twenty miles out to sea. The deep-water height of this tsunami was only about 40 centimeters when it passed them and yet, when it arrived on the shore, it had transformed into huge waves that killed 28,000 people, destroyed the port of Sanriku and villages along 275 km of coastline. For the same reason of low amplitude and very long periods in the deep ocean, tsunami waves cannot be seen nor detected from the air. From the sky, tsunami waves cannot be distinguished from ordinary ocean waves."

 

[Ed]

A 10' wave. Wow!

Alan: According to the NOAA information, that tsunami that devestated Lisbon, Portugal hit the eastern US coast with a 10' wave. Does this really bother you?You know, hurricane storm surges can easily be higher than that, and for alot longer. Same is true for Nor-easters.BTW, Newfoundland has a much steeper OCS than Maine to northern Florida. Also, the carribean islands are volcanic, and are in a seismically active area of the world. They also don't have a broad shallow OCS to help protect them from tsunamis.~ Relax and happy sailing to you ~ _/) ~