March 18, 2011
Cheap Tsunami Survival Ideas

Suppose you are going to choose to live in a zone at risk for a massive earthquake in an offshore subduction zone. Given that a tsunami can travel at 400 mph if the quake occurs within 200 miles of your home you will not have a lot of time to evacuate. The 2004 quake off of Sumatra took just 15 minutes for the massive wave to reach shore and for the quake off of Japan the arrival was just 30 minutes. Not a lot of time to evacuate on damaged roads full of other evacuees.

If you can not evacuate over land then what are your choices? I see 4:

  • Boating: Head out to sea in a speed boat. That means: after a severe earthquake get to a marina where you keep a speedboat and hope you can get it launched into the ocean before the water recedes in advance of the tsunami. Then get into deep water where the wave won't be as high. Unless you've got hours of warning this approach does not seem viable.
  • Duck and cover: Create an underground shelter under your home that is waterproof. One danger in this approach is that even if your shelter can survive the tsunami your path back up to the surface could be blocked. So how to guarantee you'll be able to escape?
  • Skyward: Up, up, and away in your beautiful balloon. But and store a hot air balloon where you live and/or where you work. But a cruise thru eBay turned up a 12 year old hot air balloon for $12,500.00. Pretty expensive. Plus, how long does it take to get one airborne? Also, what if the prevailing wind is toward the sea? Also, how long can you store the fuel?
  • A life raft sphere: Think of the Boston Whaler boats that can't be sunk because of their use of foam in their seats and hull. Well, imagine something more spherical or in a shape similar to an Apollo command module and with the ability to seal it from the inside. Situated on a roof top the life raft might hang together when the tsunami sweeps though. Then you'll ride the wave inland.

The speed boat seems the most expensive option. It is not clear to me the relative costs of the hot air balloon, underground shelter, or specialized life raft.

Both the hot air balloon and the underground shelter get out of the way of the high speed mass, either above or below it. After the quake happens the hot air balloon seems the safest approach if it can be executed fast enough. But keeping the fuel for it stored nearby poses a long term risk and you might not have time enough to pull it out and get it inflated. Plus, the basket where the humans stands probably better float because you are likely to land on the water.

The underground shelter does not work for apartment dwellers or those who do not plan to live where they are living long term. It is a considerable investment.

I find the life raft idea most appealing because of its relatively lower cost and ease of use. It does not guarantee survival. The wave could easily push along debris that would pierce the enclosed life raft right as the water hits it. Also, the acceleration of the life raft as the water hits could be so severe as to kill any occupants. But if every person in the affected area of Japan had been in such an enclosure when the wave hit most who died probably would have lived. Putting these special life rafts on roofs would increase the odds of getting a good lift-off that keeps you riding on top of the advancing wave.

The simplest version of the life raft could be pretty cheap. Imagine a big ball made from hard thick plastic with a heavy bottom for ballast and with foam seats built into it.

Got any other ideas on how to survive a tsunami? Or insights into the practicality of the ideas above?

Update: Tall buildings: In the comments Bruce and LAG suggest using tall buildings. It seems doable given building codes aimed at making the buildings strong enough to survive tsunami waves. In the Japanese town of Minamisanriku even the 4th floor of the hospital was flooded and only those who went up to the 5th floor survived. You can see at that link how few buildings survived. It appears only bigger buildings survived. So in theory fishing villages could be restored with 6 story tall and extremely well build structures. Then people could move up to the 6th floor.

Update II: Off-road bicycles or motorcycles: Looking at a map of the extent of the flooding (see also here it looks like the speed of a bicycle or off-road motorcycle (and an on-road motorcycle would probably work in a pinch) would let you cover enough distance to outrun a wave even if the roads are in a shambles and jammed with cars.

The off-road motorcycle runs the risk of not starting when you most need it. So an off-road bike could work as a back-up plan. Two wheel escape plans seem best out of the ideas so far. But for larger groups of people either extremely strong 6 story buildings or spherical escape pod lifeboats would be better choices.

Update III: Floatable houses: If a house not designed for floating can float out to sea with much of the house above water then imagine how well a house could do if it was designed to float. For example, use foam insulation and include foam insulation in the floor. Before you laugh click thru and look at the picture. Someone could have survived in that house's attic.

Share |      Randall Parker, 2011 March 18 10:50 PM  Disaster Survival

Bruce said at March 18, 2011 11:41 PM:

Live on the 3rd or more floor of a solid concrete block ... On a slower scale it works for Venice.

Jamie said at March 18, 2011 11:58 PM:

Your life sphere idea is likely the most workable. Which is not very.

Note that impact speed is less an issue than you make it out to be. As the wave amplitude changes due to water depth, it slows down considerably- that's actually what makes it so deadly. As I understand it, landfall typically happens at about ~45kph. Nothing to sneeze at, but if we're imagining these escape pods, padding, seat belts and perhaps inertial dampening can make it something that merely bruises.

It suffers from the lost at sea problem, too, though. Look at those houses floating in the ocean.

More generally, all of these suffer from the problem that it maybe (doubtfully) works for a few survivalist types, but isn't a societal response. Imagine everyone in Tokyo attempting to deploy their emergency hot air balloons. Or apartments or condos organizing a 30 minute response to filling escape bubbles dotting the roof with hundreds of people. Or the cost of those escape bubbles in the first place, and the opportunity cost of dotting the landscape with those, vs. solar panels or gardens.

Building codes, emergency response, rational regulatory oversight of dangerous things like nuclear plants (not to mention little sanity checks like not building them on geologically active boundaries, nationalist foof and palm greasing be damned) and personal planning are the only ways to workably materially improve survivability for large numbers of people. Emergency eject buttons are libertarian fantasy.

Mthson said at March 19, 2011 2:00 AM:

I wonder if large-scale underwater engineering projects could substantially reduce the force of a tsunami.

Steve Sailer said at March 19, 2011 2:22 AM:

Sheer elevation is of course best, whether going up a mountain or up an elevator in steel frame skyscraper. The people in the worst trouble are those who live in flat plains next to seismically troubled seas, such as atoll dwellers or river delta farmers, especially if they don't have cars.

john personna said at March 19, 2011 2:32 AM:

As I understand it, my city considers 45 feet elevation the safe line for tsunamis (southern California). My front step is 45 feet elevation, with a slow downhill out front. I had always considered that the right thing to do was get everybody out back, hop the fence, and climb the hill. This is reinforced by the news story that those who walked in Japan lived, while those that drove died. It is a short loop up hill from here by car, but you do go down hill first, and towards the ocean.

If you can see a hill, walk, or run.

LAG said at March 19, 2011 6:50 AM:

I suggest the tall steel and concrete building. That's best if you live in an earthquake zone with good building codes.

The floating ball sounds good, but fails on closer examination. For example, one of the films out of Japan showed a large (~100 foot) fishing boat caught in the incoming wave. Water carried it against and UNDER a bridge. A short time later, no boat. Flowing water carrying life-ball meets irresistible object. Hamster-like occupants do not survive.

Randall Parker said at March 19, 2011 8:52 AM:


Short of "do not live there" (which is hard to convince people to do) what alternative is there to the floating sphere? Tall and extremely strong buildings seem like the only alternative. In theory every coastal village could have 1 building 4 stories tall that can survive a tsunami.

Lost at sea: I can see a few solutions to that problem:

- Reflector material at the top of the spheres that draws attention of search aircraft.
- A small canister of helium in each sphere with an inflatable bright orange balloon.
- A hand-cranked distress signal box. Great when a search airplane is in sight. Lots of people who've been lost at sea report seeing a search aircraft that does not see them.

john personna,

But in a large section of north east Japan there is no nearby hill to climb.


I'm not saying the floating ball will succeed for everyone who gets in one. But it can be made stronger than a fishing boat by being round and small and of very strong materials.

Driving versus walking: I can't believe driving was the worst choice in all cases. It depends on the terrain, available roads, and number of people fleeing.


What would be the cost of building such an undersea structure for hundreds of miles? How does that cost compare to the escape sphere idea?

Randall Parker said at March 19, 2011 9:14 AM:

Update on the building idea: More like 5 or 6 stories would be needed. See the link I added in an update to the post. A 4th story is not tall enough. But people did survive in tall buildings as smaller and less strong buildings got washed away.

For farmers living on a sparsely populated plain a tall building is probably not a viable idea. For lower density populations lifeboat spheres seem like a more viable option.

Randall Parker said at March 19, 2011 9:18 AM:


Regards societal responses: Suppose society-level responses are not sufficient. That's too often the case, as Japan's tsunami preparations show. How to survive? You can't always get larger society to cooperate when you see some goal that you think should be shared by all. Hence the desire by survivalist types to make preparations on smaller scales

Shreela said at March 19, 2011 10:08 AM:

It might not be the brightest idea, but if it could be made fairly secure, and tall enough, what about a jungle gym dome?

Maybe because the water could flow through it, it might withstand the water's force, I don't know, so maybe engineer types could say better.

Shreela said at March 19, 2011 10:10 AM:

Hmmm, maybe I could have posted a differently named image - I was just looking at the photo, instead of the name. Sorry.

morpheus said at March 19, 2011 10:56 AM:

know the highest elevation in the city

witch would be the talest cooling tower or tallest concrete bulding such as a hospital,

go there go to the roof and enjoy the show:)

john personna said at March 19, 2011 11:01 AM:

As I said, a news report I got was that those who walked, lived. All it took for one lady was to climb the temple hill. And we saw those videos taken by people just a few meters above the maelstrom. I think you might be over-emphasizing "tall."

And as I said I actually live in (or at the edge) of a tsunami zone. I know I've got a 50-100ft hill out back.

Jamie said at March 19, 2011 11:22 AM:


I guess there are two axes to think about here -individual vs. societal, and the relative scale of the destruction. Last one first, comparative disaster analysis is difficult, but I don't think anyone would dispute that sane building codes left Japan better off than it otherwise would be. Cf. Haiti.

I suppose rich survivalists can make or commission an escape pod, sure. Maybe even a cottage industry like bomb shelters could develop.I just don't see how this works for more than a handful of people. I also question the economics of the risk analysis - we have records of 16 serious tsunamis hitting Japan since 1495. Global warming may be changing that, but I wonder what the resources put into this could be doing against other, more frequent risks, or other productive activities (see my examples of solar panels and gardens). Black swan events suck to deal with, and I don't think that will change.

JT said at March 19, 2011 11:50 AM:

I'm sorry, but this is hilarious. Personal bubble pods for everyone in tsunami zones? This makes me laugh.

If you have enough warning, getting into a boat isn't the worst idea. I live in Hawaii where we had about 5 hours warning for the Japan tsunami (luckily we were not hit very hard... this time), and a lot of people already own boats. Buying a boat for the remote possibility of a tsunami is just silly though.

The best solution, as everyone who actually lives in a tsunami zone already knows, is to simply get to high ground (either a hill/mountain or a tall building). This is free and proven to work with zero prep. I would hate to be setting up my float-o-pod only to find out with ten minutes to go that the entire system is unworkable (or ten minutes too late realize you have no way of floating inland again). How are you going to test such a system's viability? Wait for a tsunami? The lifepod-matic is a very complex solution to a rather simple problem.

Really, in the end, there is no 100% reliable answer. We're dealing with highly destructive, impossible-to-predict events. You can prepare in certain ways—for instance, having a stockpile of food/water/batteries/etc for dealing with the aftermath—but there is a level of preparation where the returns significantly diminish. I think the bubble-boy pod of survivability is well past that line.

Randall Parker said at March 19, 2011 12:20 PM:


I am not picturing an inflatable pod. I am thinking solid thick plastic or fiberglass molded into a sphere with a hatch the top and ballast at the bottom. No set-up time. You roll it outside (or pull the tarp off it on your roof), get in, close the hatch, and wait for the flood. Getting ready should take a minute or two.

The best solution: it only works when it is available. Some areas have large flat plains.

Hawaii: If one of the islands has a large piece fall off then you won't have hours of warning.


Building codes for earthquakes are a good idea. California's codes have gone thru a series of tougher revisions as each quake has demonstrated new failure modes. The problem is that landlords (effectively) oppose mandatory upgrades for older buildings.

Escape pod cost: I do not see why it should be expensive in its simplest form. Picture a sphere of 5-10 feet in diameter made of thick plastic or fiberglass with a hatch and ballast on the bottom. How can that be expensive to manufacture?

Floating inland: You need a way to draw attention to yourself to get rescued. How about hand-cranked or solar-powered distress signal transmitter with GPS built in?

James Bowery,

First you've got to grow the tree. Or build the tower.

john personnna,

See the update to the post where 4th floors of buildings got their internals carried away by the flood.

Your hill out back: That works for you. But it does not work for the areas that lack the hill.

JT said at March 19, 2011 12:21 PM:

Also, the underground, waterproof shelter is an even worse idea than personal bubbles. Talk about "no way to test short of an actual tsunami." Might as well keep a coffin down there too.

Fat Man said at March 19, 2011 1:41 PM:

Where I live, I am at 800' above sea level and 50' above the closest body of water. There are no known faults, Tropical cyclones have to cross hundreds of miles of dry upland to get here. We have never had a tornado higher than F-1 and those only about once every 5 years.

I have encouraged the Governor to make a pitch for building a bunch of nuclear power plants along the big river south of here in the sparsely populated south-eastern quadrant of the state where they could be in the hills for protection but have easy access to lots of water.

Fat Man said at March 19, 2011 1:46 PM:

This driver had the bad luck of being on a coastal road in Japan when the tsunami hit. He had the good luck to make it through alive. And he had the amazing luck to have a video camera going while it happened, capturing the tsunami crashing into road and car.

The driver says he had no choice but to keep going: “When I turned the corner I could see the wall of water. At that moment I could do nothing else but keep driving,” London’s Telegraph quotes him.

“Water came up and the car was floating in the water. I was panicked, the water was probably two meters high. If I came out of the car I thought I would be caught in the water as well so I thought I would wait until it had come down.”

Randall Parker said at March 19, 2011 6:32 PM:

Fat Man,

So then are you advocating that Japanese people should move up onto the slopes of Mount Fuji?

Love that video of tsunami driving. Obviously this brings to mind another tsunami survival tactic: Bouyant cars. Seal them up and add lots of foam underneath. The foam would lessen road noises too.

LAG said at March 19, 2011 7:46 PM:

RP: "it can be made stronger than a fishing boat by being round and small and of very strong materials."

I've had years of experience with steel ships and experienced the force of water when it's angry. I've seen steel(!) bulkheads torn away, hulls split, and large strong stanchions ripped from the deck by nothing but a passing wave. Go with the building. If for no other reason the ball fails from the acceleration effects on the occupants as they're slammed into the various interior components. (At least I assume you want things like an air supply, etc.)

TheEschaton said at March 19, 2011 8:10 PM:

Problems with the boat and balloon are obvious and have already been discussed.

The life raft sphere idea is impracticable for a variety of reasons, but perhaps the best reason this would never be a good idea is to really take a look at some of the videos of this tsunami hitting towns in Japan. Every single one shows that what was once simply a very high wave of water quickly becomes a wall of mud, debris, fire, vehicles of all sizes, and even buildings. You can talk all you like about building your life raft out of strong materials, but to build something capable of withstanding a building hitting it, I'd think the solution begins to become even more expensive than the used hot air balloon.

The underground shelter had better be pretty deep underground and pretty robust to withstand the tsunami dropping buildings on it and eroding the earth covering it. Finally, it needs to be able to withstand the earthquake that may often precede the tsunami. Otherwise, I see no reason why this couldn't work, although again it might be expensive for a family to execute on their own.

As everyone seems to have pointed out, high ground is going to do wonders for you. But sensitive to the fact that many coastal areas are very flat, it behooves me to think of other possible solutions. My crackpot ideas are as follows:

Individual Solutions -

1. If a train or subway is available that is going to take you out of the danger zone, get to that, since it won't suffer from the traffic issues that cars would. Knowing whether or not this would move fast enough to get you out in time would be critical - know the train's speed, the distance to higher ground, and the ETA of the tsunami as well as you can before going this route. As seen in videos, it can also be a deathtrap.
2. Owning a horse might give you an edge in a cross-country bid for survival in terms of both added speed and prediction - anecdotally, animals seem to be able to predict certain types of disasters and might give you extra time to react.
3. For the real extreme sporters out there -

Social Solutions -
1. A string or even matrix of large concrete "dragon's teeth," like the kind normally used to stop tanks in WWII, only much larger and interspersed in urban areas near the coast. These structures would provide strong, tall locations for small numbers of people to hide, break and lessen the speed of the tsunami wave as it passed through the matrix, and comb some of the larger debris like ships, buildings, cranes, etc. out of the water so that structures behind them would not be struck by these objects.
2. Promote the growth of wetlands and reefs to help slow down, soak up, and otherwise lessen the disastrous impact of the tsunami. This has been proposed as a method of preserving New Orleans from future hurricanes, and I'm not sure how beneficial it would be to a much more instantaneous inundation.
3. Explode a large dam nearby to "pre-flood" urban areas below. This is definitely my craziest idea, but given that this flood would not be as destructive as the Tsunami, it would at least mean that the incoming wall of water would be met by water coming from another direction - perhaps it might suitably lessen the power of the swell? Moreover, a controlled flooding with proper evacuation via boat and hovercraft might save lives... no, this is probably just plain crazy.

Randall Parker said at March 19, 2011 8:39 PM:


I am not predicting a 100% survival rate for the sphere occupants. Sure, some will get whacked. But these are going to be fairly light objects that will tend to stay on top of the water if they can survive the initial contact.

That's the problem with the spheres: the moment of initial contact.


If you put the life raft sphere close to the beach then you might be able to get yourself up on top of the wave (and away from its front) before it accumulates too much debris on land.

The life raft sphere idea might be fixable with telephone poles as launch pads. Or launch off of the roof of a house. Even though the house is going to collapse it will provide a higher launching point.

At a low price point so far the life raft pod seems to me like the best individual solution when faced with a large flat plain and an earthquake fairly close by. Add some time for escape and maybe an off-road motorcycle makes more sense.

Move up to a higher price point and then an underground shelter makes more sense. Buildings dropping on it: depends on where you located. Farmers in fields can put their shelter closer to the ocean than their buildings.

The best social solution appears to be a 6 story building designed to survive a tsunami. They can be built since some Japanese buildings survived when all around them got wiped away.

Doug said at March 19, 2011 9:14 PM:

Ideas, like a brainstorm:


Very strongly built elevated structures shaped like a sharp ship's prow, (to split the tsunami wave, with fresh water, built at intervals for people to flee to until rescue is possible. Use natural topography if possible. Probably not effective, due to cost and inadequate space for people. And how elevated is "enough"?

A powerful jet ski (you need something with real thrust), with life jacket, helmet and jugs of water. Get out before the wave hits, and watch out for horrific undertows -- did anyone see that footage of the big powerboat being pulled around a maelstrom-like spiraling undertow during the tsunami? You might save yourself, but no man is an island -- what about your loved ones?

Bond James Bond said at March 19, 2011 10:16 PM:

Jet packs.

James said at March 20, 2011 4:33 AM:


James said at March 20, 2011 5:48 AM:

I like the jet pack idea Bond James Bond. Perhaps we could add a "winged suit" and parachute.

Mthson said at March 20, 2011 2:13 PM:


Jamie said at March 20, 2011 3:23 PM:

"Building codes for earthquakes are a good idea. California's codes have gone thru a series of tougher revisions as each quake has demonstrated new failure modes. The problem is that landlords (effectively) oppose mandatory upgrades for older buildings."

How do you think landlords will feel about individuals parking escape-spheres on the roof?

Lee Valentine said at March 20, 2011 5:00 PM:

Back of the envelope calculation: the assumptions are 1500 ft.² house with 8 foot ceilings, hermetically sealed, total volume roughly 300 m³. That is a total atmospheric mass of about 450 kg and an oxygen content of roughly 90 kg, therefore, 30 kg of oxygen available until oxygen partial pressure equals that of Leadville, Colorado.

A further assumption is one person, normal weight, average resting metabolic demand; therefore, total oxygen requirement of about 0.6 kg per day.

The quantity of oxygen is sufficient to support one person for about 50 days.

Total carbon dioxide generated per person per day will be less than 1 kg. To reach a concentration of 2%, the level at which symptoms begin to appear, requires 9 kg of CO2, or about nine days.

The lethal concentration of carbon dioxide is more than four times higher, so, one person at basal metabolic demand could survive for about a month before succumbing to carbon dioxide toxicity in this hermetically sealed volume.

It does not appear you will require any ancillary equipment to either replenish oxygen or to remove carbon dioxide.

Randall Parker said at March 20, 2011 5:25 PM:

Lee Valentine,

Why would yo have to hermetically seal a floating house?

Or are you thinking about a hermetically sealed underground bunker for riding out the tsunami?

AMac said at March 20, 2011 6:23 PM:

To back up for a minute: tens of thousands of people died on March 11th. If and when it becomes possible to do a lookback, why did they perish?

I can think of a number of likely-common reasons.
* Died in the initial quake, or trapped by rubble.
* Lived on the coastal plain, not enough time to get to a sufficiently elevated place.
* Evacuated to a supposedly-safe elevation (hill or upper floor), except it wasn't high enough for this tsunami.
* Leaving by car, but caught in a traffic jam.
* Stayed put due to complacency or ignorance.
* Not sufficiently fit to move quickly (elderly, disabled).
* Stayed in the danger zone to try and rescue trapped loved ones.
* Stayed for job-related reasons (police, fire, medical).
* Survived quake and tsunami, died afterwards.

Survivalist and social-engineering ideas could have helped in some of these circumstances, not in others.

Randall Parker said at March 20, 2011 6:33 PM:


I am especially interested in your "Stayed put" possibilities, both due to choice and because unable to move. How many died because they just stayed where they were?

AMac said at March 20, 2011 6:50 PM:


Life is usually pretty forgiving of how one spends 15 or 20 minutes, but not this time. It's easy for me to imagine small decisions turning into tragedy, while the clock (unknowingly) ticks: making sure to bring the wedding album, or packing Pampers for the baby, or moving the pet birds from the first to the second floor...

And it was mid-afternoon, with kids at school and workers at the job site -- how many people went looking for family members? I expect a lot depends on whether cell service was operating in the interval between the quake and the arrival of the waves.

anomdebus said at March 21, 2011 11:00 AM:

RE: building height
It is important to keep in mind the terrain. The unfortunate city that you refer to the 4th floor looks like it is prone to funnelling. A person in an overall flatter terrain in the same location would not have needed a 5th floor to survive.

Jack said at March 21, 2011 11:00 AM:

Kiss your ass goodbye.

Ken Mitchell said at March 21, 2011 11:02 AM:

If you live in a tsunami-prone area, you have three choices.

1. Move. Beachfront property is more expensive anyway.
2. Know where higher ground is. When a major earthquake strikes, walk to higher ground. In the 2004 Sumatra quake and tsunami, Malaysian beach-goers who noticed the receding water and understood its significance, were able to walk to nearby hills and survived. The problem in Sendai is that the ground there was mostly flat, and there were no nearby hills. If there is no nearby high ground, refer to options 1 or 3.
3. In the event of a major earthquake, kiss your loved ones and say "It's been good knowing you!"

Don Fulano said at March 21, 2011 11:05 AM:

@JT "I think the bubble-boy pod of survivability is well past that line."

They laughed at Noah, too. ;-p

JKB said at March 21, 2011 11:16 AM:

First off, I'm waiting to hear the details on this hospital that the 4th floor flooded. First off, was it really 40 ft off the ground or did they start below grade on the floors. Secondly, did they really get hit by a 50' wall or did the building form a dam causing the water to rise at the building. For the most significant tsunami survival buildings, look at the beach hotels in Hawaii, especially, Hilo. They have open two or three story lobbies with the load bearing walls running perpendicular to the sea. Wave comes in, washes through, takes out all the non-load walls, furnishings etc, but flows relatively unimpeded and with less force on the structure.

Speedboat is a fools idea. Depending on where you live, you may have to go far to get into deep water, like off the Shelf. There's a video out of a Japanese CG boat that had 30' rollers hit it from the Tsunami, i.e., the wave wasn't breaking, 5 miles out. But a speedboat if caught in the outgoing tide, will lay over and then be rolled when the water returns. You'd need a flat bottom boat, which are slower but would be picked up by rising water. That happened to a US Navy boat in the late 1800s in Arica ,Peru. Boat sat on the bottom then was washed a couple miles inland and down the coast. Other ships in the harbor rolled up in their anchor chains because when the water receded they laid over on their sides.

It will be interesting to see how the inundation maps faired. Were they wrong or did they no plan for large enough tsunami like happened with the generators at the nuclear plant. One thing with Katrina was that she was a mid-range hurricane but due to blocking of water flowing to the west, her inundation was at the projected CAT 5 level.

As with any structure to deal with rapid flowing water, with debris, it must be designed to offer little profile across the direction of flow and have as few narrow spots that will permit debris to form a dam and put force on the structure. Alternative, round structures sealable to pressurized water ingress below 40 ft on deep bedrock pilings.

Bruce Dunn said at March 21, 2011 11:30 AM:

Roofs and Ramps

Japanese coastal cities swept away by the tsunami had effective warning plans, refuge points, and drills - the problem was that most of the refuge points weren't high enough.

What is needed is enough standing room above the high water point for the local population, and rapid access to the standing room. Helicopter video of the tsunami affected areas in Japan showed many people surviving on the flat roofs of substantial buildings. Local planning authorities should be looking to use whatever tools they have available to make sure that any point in a residential area is within say 500 meters of a suitable building, parkade etc. which is strong enough to stay standing in a tsunami. It doesn't matter if the lower floors are gutted by the water.

Stairs have proven to be a choke point in many disasters, so the ideal would be to have external pedestrian ramps heading up to the roofs. Ramps external to the building would allow the elderly and infirm and the young to be dropped into a wheelchair, stroller or equivalent and pushed to safety.

In practice, public buildings like schools, libraries etc. would be designed to be several stories high, rather than be large footprint buildings of one story. The ramps could be part of the normal access to upper stories of the building. Once the refuge points are established, residential areas would tend to sort themselves out according to ability of residents to respond to an alarm at 4 AM. A retirement home for example would be built with its own roof as a refuge point, or be built adjacent to a refuge point. On the other hand, young adults without children might feel secure living a 5 minute run from the nearest refuge point.

TB said at March 21, 2011 11:41 AM:

See the end of this cartoon:

The Push Button House

Patrick Lasswell said at March 21, 2011 12:13 PM:

After surviving the Sylmar quake in Los Angeles in 1971, my family followed a simple rule for surviving tectonic events: Never live (in a fixed structure) within 100 vertical feet of sea level or the nearest body of water. My years in the Navy add the fixed structure caveat, and the only time I was caught by this was a rogue wave off the Bahamas in March 1994 that knocked antennas off the destroyer I was aboard. I can say that a 10+ foot wave rushing up the forecastle of a destroyer will knock you to your knees when it hits the superstructure.

Seriously, the best way to avoid Tsunami obliteration is to not build on the flat near the ocean. Rafts are a poor substitute for elevation.

A better survival method for rafts would be a mesh of linked rafts on the top of apartment buildings, with tools for linking rafts from other apartments together. Instead of one big failure risk, a flexible linked mat that can endure loss of cells and survive is a more practical tool. Finding the guy miles out to sea on the top of his house was a glorious fluke. Finding shoals of rafts linked together for protection is a certainty. Disaster movies aside, people help people stay alive, and groups of people get higher priority for rescue than loners.

Sardondi said at March 21, 2011 12:20 PM:

Foolproof tsunami-survival method: simply live some distance inland OR on ground at least a few hundred feet above sea-level, either of which is proof against flooding and the debris field associated with tsunamis. Living away or above is imminently easier and done at zero additional cost and effort...if done at the moment of deciding where to initially make your home, and not after you've already bought a bungalow on the ocean and the waves are knocking at your door.

Choices have consequences; life is not without risk. Most people would say that those who live on and very near sea coasts face on the whole more weather-related dangers than do most persons who have decided they'd rather be safe from hurricanes and tsunamis than to enjoy the sounds of waves lapping on the beach 24-hours a day.

Kevin said at March 21, 2011 1:01 PM:

"Move to a place that is immune to tsunamis."

Just thinking out loud.

BG said at March 21, 2011 1:25 PM:

Bangladesh, which consists largely of a low-lying coastal plain, has built towers to serve as shelters from cyclones ( They seem to have cut the death toll substantially. Maybe something similar could help against tsunamis, if the residents get enough warning.

Ryan said at March 21, 2011 1:37 PM:

OK I see a lot of people with the answer of: "Build higher up." Either with a strong tall building or on a mountain. The only problem with that is "How high is high enough?" What makes 100 ft more or less likely then 95? or 104? 2 feet of rushing water can be deadly. I like the life raft idea. If it uses a CO2 inflation device and is built to be semi sealed with an inflatable roof (spherical might work). Add a small hand held transponder and an anchor to lower the risk of getting lost at sea. I know they have hard cased pods that fit inflatable rescue rafts on ships. I'm sure it wouldn't be too hard to build them for houses. Just climb to your roof, open canister, wait 30 seconds while you help grandma and the kids up the ladder, step in and seal doorway. When the wave comes it can whip the house out from under you. Maybe attach a 1000ft of rope from the bottom of the raft to a 500lb block of concrete buried in your back yard, that will stablize and slow you down but give you enough motion to ride out the worst of it. Even if it gets drug under water for a few moments you will eventually bob back to the surface and as long as you are still in the raft you should still be ok. I'm guessing if we made enough of them, the cost could be under $500 each.

arminius said at March 21, 2011 1:39 PM:

Nobody's said "TARDIS" yet?

And you call yourselves geeks. Sheesh.

ryan said at March 21, 2011 2:12 PM:

TheEschaton: I like the idea of dragon teeth. It might not stop it but it could help. They also makes a nice defendable beach :-)

Kathy Kinsley said at March 21, 2011 3:07 PM:

One thing the Japanese could do in the already affected areas is build hills (from the debris). Google for tornado hill. That one is only 40' high, but it started as a landfill (a hole in the ground).

Carey J. said at March 21, 2011 3:15 PM:

Here's the escape bubble I want.

JC said at March 21, 2011 4:01 PM:

The hot air balloon takes a long time to heat up and fill, along with multiple people to control various pieces while filling. I don't think that's going to be very viable. However, one possibility for the individual person is an ultralight. Parachute or hang glider model. Pop out wings, turn on engine and go. Not really sure what air turbulence is like above a major tsunami like that.

Sam said at March 22, 2011 1:18 AM:

I have trouble understanding the rejection of the bubble idea. It's seems the most cost effective and doesn't need anyone elses approval. Make it in your backyard. Made of solid foam about 1 foot thick and covered with fiberglass. Rutan made planes out of the same material. Super strong. It could be made into a piece of furniture. Like those hippie shell chairs with speakers from the 70's. Throw out the cushions and lock the shell closed. Ready to go. Since it's round it wouldn't get caught easily like the boat did in Japan under the bridge. It would roll off debris. The foam inside would cushion shock.

anon said at March 22, 2011 2:04 AM:

Oxygen tank/scuba diving equipment. If inundated, hold on to something bolted down. Wait for deluge to subside.

Art said at March 22, 2011 5:48 AM:

Any idea how far inland one needs to travel to be safe? Some of the reports I have seen stated the tsunami traveled anywhere from 6 to 12 miles inland. Obviously it can vary as the elevation changes will impact how far in the wave can travel.

I cant help but think of my yearly trip to the North Carolina shore and what would occur to the east coast if a tsunami struck. The logistics of evacuating a large population in a short amount of time (30 minute warning) is just not possible.

AMac said at March 22, 2011 5:58 AM:

The reach of the March 11 tsunami is depicted on this map of the Sendai area.

Patrick Lasswell said at March 22, 2011 10:01 AM:


Bubble failure points:
1. Spear failure. Pole-like debris will puncture the hull. When this happens while the pole is still attached to something solid, the wave can overcome the buoyancy of the bubble and drive the ball down onto the pike. Escape in this circumstance becomes unlikely.
2. Hatch failure.
a. Human: You remembered to close the door in the middle of the greatest panic of your life right?
b. Structural: How much did you pay for that hatch.
c. Sealant: What did you use to seal the edges.
d. Rescue: You put a handle that works for the outside in case you are knocked out, right? How did you keep the debris from opening that handle?
3. Scope failure: The surrounding buildings/terrain made the wave how big? Crunch.
4. Stability failure, Yaw: Without significant spin dampers, even with ballast the bubble could readily start spinning fast enough to cause a variety of failures. The speed of the skin of a spinning bubble is going to add to the damage dealt by debris impact. Energy is mass times velocity SQUARED! With a large enough ball, you can generate sufficient spin to pin you to the edge of the hull until you die from other causes.
5. Stability failure, Pitch/Roll: If the ballast de-laminates or is insufficient, the ball will go into a roll and you will get beaten to death inside of it unless you are fully strapped in, especially your head/spinal cord.
6. De-lamination failure: When the hull is repeatedly struck by debris, the underlying foam will compress and lose buoyancy. When it de-laminates the structural strength of the hull will reduce precipitously and increase the likelihood of leakage. Leakage will act to spread de-lamination. One probable failure mode will be the ball essentially intact except that it is full of water except for the foam filling the top of the bubble. In cold water this means you will likely die of hypothermia before drowning, but in warm water you can drown before you freeze.
7. Visibility failure: Everything went just great until the ball floated downwind into the burning fuel. The foam insulated the ball just great until it started melting...

If you want me to continue I'm going to have to start charging you.

Randall Parker said at March 23, 2011 12:26 AM:

Patrick Lasswell,

Yes, lots of failure modes. That does not mean that most of the spheres will fail though. The spheres would increase one's odds of survival if one happened to live in a low coastal plane and had otherwise low odds of getting away via other means.

JKB said at March 25, 2011 2:27 PM:

First, look at the inundation maps. But check the tsunami size used to create those maps. Some coastlines and islands are not severely impacted because they rise sharply from deep ocean and the walls cut the legs out from under the tsunami. Others have long gentle slope which will funnel the energy until the wave reached biblical proportions. Look at tidal basins and rivers which will funnel the energy/and water deep inland and may come around from behind you if you are looking out to sea. And if you are on the East Coast of the US, you are screwed if you are below the Appalachian foothills, but then there are no historical vertical displacing earthquakes in the Atlantic basin. There is a theory that the parting of the Red Sea was a tsunami though. And about 10 years ago there was some speculation about a big gas bubble off Maryland or Virginia that could burp and cause a wave. And then there are the great cataclysmic events such as when the craters that Oahu is the remnant of slumped off and washed water up hundreds of feet up Lanai as evidenced by sealife deposits and may have splashed over. Although strictly that isn't a tsunami since the entire water column wasn't displaced but just a really big splash.

carlos luis martin fernandez, ARCHITECT said at September 3, 2011 5:01 PM:

Other solution: an air bell anchorded on the floor. It is as a bubble of air, inside a construction as a bout turned down. And people refuges inside that construction. So the entrance is under the construction. And the water of the wave would be what closes the door.
Otra solución: Una campana de aire anclada al suelo. Es como la burbuja de aire que queda bajo un barco puesto bocabajo. Y la gente se refugia en ese construccion. La entrada seria debajo de la construccion. Y el agua de la ola seria la que cerraria la puerta para que no se escape el aire de respirar.

Shelly said at November 10, 2011 2:18 PM:

What about the tourists & visitors who are oceanfront and not prepared for a tsunami? They don't have a plan of action. If any of them are fortunate enough to survive, I'd pray that they were carrying international health insurance as many of the survivors were critically injured. We all know that most major medical coverage doesn't apply once you leave your own country. If I were a permanent resident in a tsunami-prone area, I would definitely consider moving inland after the horrific tragedies we have seen. I don't believe any of the 4 choices in this article are viable options.

Daria said at March 15, 2012 7:50 PM:

Wouldn't it be better to build a triangular raft? It is a triangle so it would be harder for the waves to knock over and it would not break up as easily as a square-shaped raft. Also it doesn't seem expensive, all you need is wood and large barrels.
p.s. by triangle i mean a fully enclosed shape like the roof of a house not a flat surface

Jon said at September 6, 2013 5:19 PM:

Tsunami's don't last long. All you need is a concrete room that won't get washed away and a scuba tank.

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