Suppose money was no object and you insisted on living in a high risk tsunami zone (if there is such a thing)
Is it possible to engineer and build a breakwall to completely protect your house from any future tidal waves? Remember, money is no object, could it be done?
A wall that would completely protect your home from 100 foot waves.
Could it be done, and how difficult would it be?
We were debating this over the dinner table and I thought it would not be possible.
Regards
Sure. The Japanese have them. Be prepared to fork over, though - They ain’t cheap, and if you’ve got a lot of miles of coast…
If you’ve seen videos from the recent tsunami, you may have noticed how several were shot from the second floor. So, skip the wall and build your house sort of like they build beach houses here on the Gulf Coast - second floor and above is house, and the first level is just stilts to hold the thing up. You don’t keep anything of value on the first floor, and if it has any walls, they must be of a break-away design.
I saw this on one of the cable networks, so take it with a grain of salt, but there’s no upper limit to the size of a tsunami. Earthquake caused ones can reach only about 40 feet high, but one’s caused by rockslides have reached 450 feet. There’s a hunk of the Canary Islands that is set to fall into the ocean and when it does, it’ll create a tsunami over 400 feet high. So depending upon where you want to locate, you might have to build a considerably high wall.
A Gulf Coast Defense wouldn’t be effective against a significant tsunami, especially as depicted in the OP. Part of the challenge among the larger tsunami, in particular, is they ride atop a massive swell–a heightened sea level. The resulting hydrolic battering ram would easily splinter stilts like popcycle sticks.
To block a 100-foot sea wave, especially one moving at 40-50 mph, would require a dam-like structure of enormous size and fortification. I’m guessing the wall could be shaped to dissipate the wave, without taking on the full brunt of the wave.
Much easier to site your house on a 200-foot cliff.
Whatever you build will be built to certain design parameters. If you’re anticipating 100 m tsunamis, forget it - move inland. But if you’re designing for riding out a 10 m tsunami (which we’ve recently seen can do some damage and cause some deaths), a stilt design can work. Look at all the second floor video from Asia and India.
As noted in the article I linked, the Japanese walls are designed to deal with 300 meter, or essentially 100 foot, waves. That is what the OP was asking about, and it’s off-the-self engineering, if you’re willing to pay for it.
Ooooops!
Make that 30 meter waves, not 300!
:o
note to self - posting while sick leads to very silly typos…
Build yourself a retractable airtight plexiglass dome. Earthquake or rockslide nearby? Push a button, dome sides close together, keep a 30-minute supply of breathable air on hand, and you’re set. Right? Instead trying to ride on top of the wave or deflect the entire force, the dome would just direct the water over and around the house.
Ever seen a ladybug ride on your car window or windshield for quite a ways after you’d figure they would blow off? Same principle.
The article says: “But these walls are rarely more than a few metres high, and would not have fully protected against the tsunami in the Indian Ocean in December.” It doesn’t seem to say anything about protecting against 30-meter waves.
I’ve been to coastal villages and towns in the Sanriku region (northeast coast of Japan) where a tsunami killed 22,000 people in 1896, and another killed 3000 in 1933. People seemed to take the tsunami threat very seriously, and there are warning sirens everywhere. But I didn’t see any walls.
By the way I think the BBC article is incorrect about the Hokusai painting. I’ve never heard it claimed that it depicts a tsunami.
If it’s the painting that I’m thinking of, then I’ve always heard of it being referred to as a tsunami.
You mean this one? There’s nothing in the picture or title to suggest it’s more than an exaggerated depiction of a rough sea. And other pictures in the series depict ordinary scenes, not extraordinary events.
Yup that’s the one. I’ve always seen it captioned indicating that it represented a certain tsunami.
I used to live in a small fishing village on the Pacific coast that was hit by a very small tsunami last year and a fairly large one in 1944 that killed many people.
There most certainly were walls to protect houses that were immediately by the ocean. I only found one tiny picture of one of the walls. (Wall is on the right, ocean and small fishing port on the other side.) As you can see by the cars, the walls aren’t spectacularly tall but they would have been enough to prevent a lot of the flooding that occured in 1944. These walls are also meant to prevent flooding caused by typhoons, which are much more common than tsunamis. Also, there is a system of concrete wave-breakers that absorbs part of the impact before the waves reach land.
There are not only sirens but full-fledged P/A systems. We had IIRC two tsunami evacuation drills per year. Loudspeakers installed throughout the village broadcast the evacuation order as well as the estimated time of arrival of the tsunami. Villagers then head to designated safe spots. Every neighbourhood has volunteers (same guys who were volunteer firemen as far as I could tell) to help coordinate evacuation.
When there was the small tsunami, last Septembre, they were giving minute-accurate estimates of when the wave would hit various parts of the coast on the news. It was only about 1m high but nevertheless several boats were damaged in my old village. If the wall in the picture hadn’t been there, the houses you see on the left would have been damaged too.
What about a wedge…like you may see on some plows?
/////////\ --tsunami
/\ -- tsuanmi wedge (break-wall)
/ \
/ \
/ x \
\
\houseThat didn’t come out that great at all…something like this:
Plow Wedge
I doubt the amateur videotape footage we saw on television–those that shower beachside homes having actually survived–were hit by 10 m (nearly 35 foot) tsunami. I think most of these tsunami were “only” five to 10 feet high, yet wiped out entire cities and villages. I don’t think any video exists showing an actual 10 m wave crashing ashore, or of beachside huts/buildings surviving such devastating impact.
I’ve never seen a house on full 35-foot stilts. But remember this: the seismic sea swell typically elevates the entire sea level, which then allows a monstrous (35-foot) wave to roll ashore on top of that. That’s one hell of a battering ram. What the wave didn’t obliterate, the soil erosion leading to structural foundation problems probably would, IMHO.
This was detailed in a Discovery Channel episode currently airing. I can’t remember the name of the island, but scientists are predicting a volcanic landslide in the Atlantic that could trigger a mega-tsunami in excess of 1200 feet high. And yes, it would be on the west side of the island, which would send it straight toward the east coast of the United States. The wave would arrive about six hours after the landslide, and it would certainly ruin your day. They didn’t speculate on how far inland it would reach, but hey - the highest point in Rhode Island is only some 900 feet above sea level. This wave is taller than practically any building on the east coast.
Sleep tight.
Canary Islands. As noted in post #4 above …
The History Channel recently had a “Nature Tech” story that included info on some of Japan’s tsunami defenses. The northern town of Taro (sp.?) had 2 tsunamis, in 1896 and 1933. They killed 20,072 and 3,000 respectively, with the latter wave being 95 feet high. In 1934 they started building a series of seawalls appearing to be about 30 feet high and with the seaward side sloping down to the beach at about a 45 degree angle. It has rectangular indentations to help dissipate wave energy. There are 6 openings about 12 feet tall with massive 2-ton steel doors that take a crew of 3 volunteer firemen to close and secure them. One man stays on the seaward side to lock them. He then has to climb a stairway to get over the wall. It was said that the walls were built to the hight of previous tsunamis but that was no guarantee they would suffice for higher waves in the future. They also have tide gauges and tv surveillance of the waterfront to give additional info after a warning is received that a 'quake has occurred that could cause a tsunami.
The program also mentioned evidence found in 1953 of a “magatsunami” that had hit Lituya Bay, Alaska, that was wiped out all vegetation up to the 500 foot level. . An oil prospector, George Plafker, now a Ph.D. with the USGS, saw that the old growth tree line was up so high and wondered about it for 5 years. In 1958, Howard Ulrich and his 8-year-old son were on a boat in the bay and saw a massive landslide on its other side. The wave from it carried the boat into the treetops and back to the bay and wiped out all vegetation on the shore up to an elevation of 520 metres or about 1,640 feet above sea level. He contacted Mr. Plafker and his investigation showed the immense power of what are called megatsunamis.
The program then reported on the volcano, La Coimbra Vieja (sp.?) on the island of La Palma in the Canary Islands. A 1949 'quake there resulted in a 12-metre drop in the west side of the south end of the island. The prediction is that it will slide into the sea, causing an up to 1200-foot high wave to reach the US east coast in 8 hours. No estimate on the timing. The wave size depends on the size of velocity of the rockfall when it hits the water.
This week the US reported that they will be installing a tsunami warning system in the Atlantic over the next 2 years at an estimated cost of $20 million IIRC.
The Pacific warning system, Deep Ocean Assessment and Reporting of Tsunamis (DOART), was installed by the USA in the Pacific after the 1949 tsunami that inundated Hilo, Hawaii, with a 30-foot wave. 26 other Pac countries joined in that effort after the 1960 tsunami that hit Chile, killing more than 2,000.
The Pacific warning system consists of 100 surface buoys sensing wave action and 6 ocean-bottom sensors that are tethered to surface buoys. The deep ones measure the weight of water above them. All data are sent hourly to satellites and then down to ground station(s?) whence warnings are issued. Presently it is one-way communication from the sensors up, but they are working on two-way so they can query the sensors at any time. It takes only two minutes to read the data, but longer to decide on, and then to issue, warnings.
/cite/ notes taken during a rerun of the program. There may be some e-links.
