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Earth Science

The Largest Recorded Tsunami Was 50 Years Ago 323

An anonymous reader writes "July marks the 50th anniversary of the world's largest tsunami — a 1,720-foot-tall wave in Lituya Bay, Alaska. It was triggered by a chain reaction of events that began with a magnitude 7.7 earthquake on the Fairweather Fault, which dislodged a rock fall of 40 million cubic yards, that fell 3,000 feet and splashed into the northwest end of Lituya Bay to generate the wave. This article includes survivor accounts, maps, a satellite image, and photos taken right after the event." To be fair, eyewitness accounts put the height of the wave as it came toward their boats at perhaps 100 feet. The tsunami scoured the land of vegetation and soil to a height of 1,720 feet above sea level, however.
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The Largest Recorded Tsunami Was 50 Years Ago

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  • Feet and yards? (Score:4, Insightful)

    by Squapper ( 787068 ) on Wednesday July 16, 2008 @07:09AM (#24210629)
    I live in the 21:st century, you insensitive clod!
    • Re:Feet and yards? (Score:5, Insightful)

      by Eddi3 ( 1046882 ) on Wednesday July 16, 2008 @07:14AM (#24210657) Homepage Journal

      In all seriousness, this happened in the US, so I'd say it's only fitting that the units of measure are ones that Americans use.

      • Re: (Score:2, Insightful)

        In all seriousness, this happened in the US, so I'd say it's only fitting that the units of measure are ones that Americans use.

        I agree. Because if this would have happened in france, it'd be only fitting that these news were in french.

        Only reason to use american measurements would be if this would be aimed directly for americans. If so, why post it on international site (I think that the majority of people browsing this site aren't americans. Are there any public statistics?)

        Then again, I don't know who is this aimed to. Why is this on "News for nerds" site as it isn't really news or for nerds... So I don't personally care which me

        • Re: (Score:2, Insightful)

          I get so sick of this debate. This is US data from the 1950's, it makes sense to present it in the manner that it was measured. We're not talking ells here. Is it really that hard to divide by 3? Is it that hard to look up a fathom?

          There is nothing inherently superior about the metric system. Why does dividing by 10 matter so much, anyway? Because you have 10 fingers? Really, we should be trying to move to a system of measure that is base 2.
          • Base ten (Score:5, Insightful)

            by sjbe ( 173966 ) on Wednesday July 16, 2008 @07:51AM (#24210971)

            There is nothing inherently superior about the metric system.

            Sure there is. Ease of unit conversion and ease of communication with the REST OF THE FREAKING WORLD. We live in a global economy - we should start acting like it.

            Why does dividing by 10 matter so much, anyway? Because you have 10 fingers?

            Because we use a base 10 [wikipedia.org] counting system for most calculations. Having a measurement system that is highly compatible with the numeral system most humans use makes sense.

            Really, we should be trying to move to a system of measure that is base 2.

            Really? Go ahead and tell your mother you came 1011 miles to see her - I'm sure she'll be impressed.

            • Re: (Score:3, Funny)

              by Aglassis ( 10161 )

              Why does dividing by 10 matter so much, anyway? Because you have 10 fingers?

              Because we use a base 10 [wikipedia.org] counting system for most calculations. Having a measurement system that is highly compatible with the numeral system most humans use makes sense.

              Really, we should be trying to move to a system of measure that is base 2.

              Really? Go ahead and tell your mother you came 1011 miles to see her - I'm sure she'll be impressed.

              I'd prefer that we used a hexadecimal system. It is large enough for brevity but also can readily be converted to binary for simplicity. The only advantage a base-10 system has over hexadecimal is that most people have 10_(10) fingers so they know how to count to 10_(10). If they were smart, they'd know how to count to 0x3FF (1023_(10)).

              • The Mom Test (Score:3, Insightful)

                by sjbe ( 173966 )

                I'd prefer that we used a hexadecimal system.

                And how do you propose we convince every non computer geek in the world that this is a good idea? Further are you going to pay for the math classes virtually everyone will need?

                Your idea fails the mom test miserably...

            • I am comfortable in both systems, and as necessary I will calculate conversions between them. Why the big fuss over 50 year old data?

              Stop being a cry-baby.

              • by sjbe ( 173966 )

                I am comfortable in both systems,

                So you are just like most of the people reading this, myself included? Good for you.

                and as necessary I will calculate conversions between them. Why the big fuss over 50 year old data?

                You didn't hear me making a fuss over it. I did however reply to someone whining about how metric has no advantages which is 95% of the worlds population seems to disagree with.

                Stop being a cry-baby.

                We're all really impressed with your unit conversion prowess. I bet you pick up all the girls by showing off how you know metric AND imperial units.

            • Metric bah (Score:5, Funny)

              by jimbolauski ( 882977 ) on Wednesday July 16, 2008 @08:39AM (#24211475) Journal
              You go ahead and pay $4 for a liter and I'll pay $4 for a gallon, that fact alone is reason enough to stick with US measurements.
            • by AlpineR ( 32307 ) <wagnerr@umich.edu> on Wednesday July 16, 2008 @09:01AM (#24211833) Homepage

              "Grandma, I walked eleven miles to see you."

              The funny thing about non base-10 number systems is that our language can't say them without spelling them out. The old joke about "There are 10 kinds of people in the world..." isn't very funny if you say it aloud or in your head: "There are two kinds of people in the world" or "There are one zero kinds of people in the world".

              So I believe it's our language, not our fingers, that makes base ten feel natural. If we had grown up accustomed to counting "one two three ten eleven twelve thirteen twenty twenty-one twenty-two twenty-three thirty" then base four would feel natural. The characters "2506" would look as strange as hexadecimal and be as impossible to pronounce without spelling or conversion.

              By the way, isn't the term "base 10" devoid of meaning? If our system were base four, then "base 10" would mean "base four" since the characters "10" in base four mean "4" in base ten. Whatever base you use, "10" is your way of writing the value of that base.

              Back to the tsunami, it's disappointing to hear that the water was 290 fathoms high only very near it's source (the landslide). That's like saying "Your mama's so fat she jumped in the Pacific and made a tsunami a billion nanometers high."

            • Because we use a base 10 counting system for most calculations.

              I'm not installing a new system until time and angle measurments get upgraded to base 10.

            • Re: (Score:3, Interesting)

              Sure there is. Ease of unit conversion and ease of communication with the REST OF THE FREAKING WORLD. We live in a global economy - we should start acting like it.

              Ease of conversion? Are you kidding? It's no easier to convert in either system, unless you only can do math in your head at the moment. Then the metric system has the advantage. If you have some sort of calculator (y'know, most of the time), it's dead easy either way.

              Ease of communication doesn't cut it, either. By your logic, we should all be using the same language, and cursing out those heathens who refuse to abandon the language that they're used to. Yet we're not... we accept that people do things in

              • Re:Base ten (Score:5, Insightful)

                by Anonymous Coward on Wednesday July 16, 2008 @10:46AM (#24213903)

                we should all be using the same language, and cursing out those heathens who refuse to abandon the language that they're used to. Yet we're not...

                Genau meine Rede. Wir sollten einfach alle weiter unsere eigenen Einheiten verwenden und unsere eigene Sprache sprechen. Es macht nämlich zu viel Arbeit, das alles neu zu lernen, nur um mit anderen Menschen kommunizieren zu können und um willkürliche Umrechnungsfaktoren unnötig zu machen. Solche Anstrengungen sind wirklich zu viel verlangt, und bisher hat auch niemand diese Mühen auf sich genommen. Das ist leicht daran erkennbar, in wie vielen verschiedenen Sprachen alleine in diesem Forum Kommentare geschrieben werden. Wer Sarkasmus findet, darf ihn behalten.

              • Re:Base ten (Score:4, Insightful)

                by sjbe ( 173966 ) on Wednesday July 16, 2008 @10:58AM (#24214159)

                Ease of conversion? Are you kidding?

                Not a bit.

                It's no easier to convert in either system...

                If you want to believe that dividing by some arbitrary conversion factor is easier than moving a decimal you just go right ahead believing your delusions. By your own arguments it's the same difficulty with a calculator and metric is easier without one. QED metric is easier overall. You should be disappearing in a poof of logic right now.

                Ease of communication doesn't cut it, either.

                Riiiiiight. [wordpress.com] Because unit conversion mistakes never occur and it's MUCH easier to do unit conversions than to just use the same measurement system everywhere.

                Even ignoring social issues There is a measurable economic cost to using multiple measurement systems. It adds unneeded complexity to business, engineering and scientific endeavors especially those that cross international boundaries.

                By your logic, we should all be using the same language...

                I don't recall ever saying that and I would have said that if that is what I meant. However, English has become the de-facto language of international commerce and scientific discourse if you want to get picky about it. No need to "curse the heathens" since 95% of the world seems to realize that a common measurement system is a useful thing.

                Besides imperial units these days are defined against metric units. An inch is explicitly defined as 2.54 centimeters [wikipedia.org]. So you're using metric whether you realize it or not. Why not just cut out the complication and use the real thing?

          • Re:Feet and yards? (Score:5, Insightful)

            by Anonymous Coward on Wednesday July 16, 2008 @08:37AM (#24211437)

            "There is nothing inherently superior about the metric system."

            Of course there is. It uses powers of ten, which is easy math, it's trivial to relate volume-mass-distance measures (1cm^3=1mL water=1g, 1m^3 of water = 1000kg = 1 tonne), it doesn't have half a dozen wacky variations on the same damn unit (it was 5 ounces: would that be the International avoirdupois ounce, the International troy ounce, the Apothocaries' ounce, the Dutch metric ounce, the Maria Theresa ounce, or, wait, is it possible you mean one of the 3 variations of fluid ounces?). It's the same messy story for "pounds", "gallons", and so on. If you're lucky there are only 2 common versions.

            I mean, yes, you're right, it's just a matter of convention and units are always interconvertable, but to say there isn't anything inherently superior about the metric system is nuts. What's convenient about remembering that miles have 5280 feet? Oh, wait, just to be clear I meant an international mile, not the U.S. survey mile (5280 survey feet) or international nautical mile (about 6076 feet). (AAAAAUGH!)

            Have you ever noticed that virtually ALL Imperial units are now defined in terms of the metric system? An inch isn't an inch anymore, it's 2.54 centimetres exactly. There's a reason for that -- because the metric system isn't built on a shifting sand of dozens of different archaic national standards and conventions for their usage.

            The only thing better about the Imperial system is a metric buttload of inertia in people's brains and the convenience of powers-of-two fractions for some measures. But you can use powers-of-two fractions to express things in metric too if you want.

            If you like the Imperial systems please stick with one of them, but you'll never convince me that the metric system is merely on par, especially for anything scientific.

            • Re: (Score:3, Funny)

              by shrikel ( 535309 )
              Sorry, can you tell me what a metric buttload is in imperial units? I don't know the conversion ratio.
          • by TheLink ( 130905 )

            Yeah this debate is getting quite boring, especially since it keeps appearing on slashdot.

            If people here can't do rough conversions in their heads (it's not as if we need such high precision in most of such stories) at least a _slashdotter_ should be able to use google to do it.

            Here you go:
            http://www.google.com/search?num=100&hl=en&safe=off&q=40+million+cubic+yards+in+cubic+meters&meta= [google.com]

            http://www.google.com/search?num=100&hl=en&safe=off&q=1720+feet+in+meters [google.com]

            People complain about

        • Re:Feet and yards? (Score:5, Insightful)

          by steveo777 ( 183629 ) on Wednesday July 16, 2008 @08:13AM (#24211179) Homepage Journal

          I'm an American and I would so much rather see everything in Metric. I think the main reason this is in the old, crappy system is not because it's written 'for us' or whatever, but because of the year it happened. Though I would think that the guys collecting the data would use metric anyway...

        • From the FAQ:

          Slashdot seems to be very U.S.-centric. Do you have any plans to be more international in your scope?

          Slashdot is U.S.-centric. We readily admit this, and really don't see it as a problem. Slashdot is run by Americans, after all, and the vast majority of our readership is in the U.S. We're certainly not opposed to doing more international stories, but we don't have any formal plans for making that happen. All we can really tell you is that if you're outside the U.S. and you have news, submit it,

      • Re: (Score:2, Insightful)

        by thc4k ( 951561 )

        I thought this is the internet.

        100 feet = 30.48 m
        1720 feet = 524.26 m
        3000 feet = 914.4 m
        4e10 yards**3 = 3.658e10 m**3
        7.7 on the Richter scale = 355e9 ton TNT = 1.484e18 J

      • Re: (Score:3, Insightful)

        by Z00L00K ( 682162 )
        Maybe it's time for the US to upgrade.
        • Re:Feet and yards? (Score:5, Interesting)

          by Thelasko ( 1196535 ) on Wednesday July 16, 2008 @08:16AM (#24211215) Journal
          We tried, we even have the metric conversion act of 1975. [nist.gov] There are simply too many people who resist change and can't do the math in their head. I understand the difficulties with Fahrenheit to Celsius, but it isn't hard to multiply a pound by 2.2. You can even round it to 2 if you had to.

          I used to work in a factory that was owned by a German company, but located in the US. If I would give a drawing labeled in milimeters to our machinists they would balk at it, and I would have to go back and convert it to inches. We had a visiting machinist from Germany and I accidentally gave him a drawing in milimeters to use with our mill which was in inches. Realizing my mistake I offered to correct the drawing. He simply asked what the conversion was. I told him 25.4 mm/in and he came back a little while later with a perfectly machined part.
          • Re: (Score:3, Funny)

            by bberens ( 965711 )
            I blame women. No woman wants to go from weighing 95 units to weighing 209 units. It's like the designer clothes stores that makes their size 4 dress the same size as the cheapo brand size 6. Women will want to buy the size 4 because it makes them feel skinnier. You might have a better chance of getting us to measure weight in stones.. then our same woman would weigh just under 7 units.
            • Re:Feet and yards? (Score:5, Informative)

              by radio4fan ( 304271 ) on Wednesday July 16, 2008 @08:36AM (#24211427)

              I blame women. No woman wants to go from weighing 95 units to weighing 209 units.

              Great theory, but there are 2.2lbs in a kilo, not 2.2kg in a lb.

              So a 95lb woman weighs about 43kg, not 209kg.

            • No woman wants to go from weighing 95 units to weighing 209 units.

              Congratulations, you did the conversion backwards. A kilogram is 2.2 pounds, not the other way around. A woman who weighs 95 pounds weighs 43 kilograms, not 209.

            • Don't get me started on dress sizes.
          • it isn't hard to multiply a pound by 2.2.

            Except that you wouldn't want to multiply a pound by 2.2. You'd want to *divide* a pound by 2.2, or, going the other way, multiply a kilogram by 2.2.

            • Re: (Score:3, Funny)

              by Thelasko ( 1196535 )

              Except that you wouldn't want to multiply a pound by 2.2. You'd want to *divide* a pound by 2.2...

              That's an imperial kg, a US kg you multiply. Maybe that's why the US never switched to the metric system.

              end sarcasm

    • Re: (Score:3, Insightful)

      by rodney dill ( 631059 )
      This happened 50 years ago in the US with the 'reporting' done by Americans. They used the measurements of the place and time. There is no need to go back and convert everything to metric.
    • by smoker2 ( 750216 )
      Yeah coz we all know that in this century, do not ever expect any body to actually think on any subject. You must supply an easy to digest baby mush of information so as not to cause the viewer too much inconvenience.
      I mean you only have to google the words measure & yard once in your entire existence, but nope, either you get it your way or you bitch.
      FFS, if you don't know by now that 1 metre is approximately 1 yard or 3 feet, then you don't get out much. And if that is too inaccurate for your purposes
    • Re: (Score:3, Interesting)

      by rossdee ( 243626 )

      Surely the size of the wave should be measured by the VOLUME of the water displaced, rather than the height.
      This one was confined in a bay at its source, so it was very high, but I'll bet the Boxing day 2004 tsunami involved a lot more water, whether you measure it in litres or hogsheads.

  • Canary Islands (Score:3, Informative)

    by mike2R ( 721965 ) on Wednesday July 16, 2008 @07:17AM (#24210673)
    There was a scary program on UK TV a few years back talking about the possibility of something similar happening in the canary islands that would wipe out the eastern seaboard of the US - a little research [google.co.uk] seems to suggest this is greatly overhyped however.
  • by Splab ( 574204 ) on Wednesday July 16, 2008 @07:20AM (#24210709)

    states they where on 5 fathoms = 30 feet of water, the wave was 100 feet high (I'm guessing the guy means 100 feet above normal level) so that makes the wave 130 feet (40 m.) That is one fudging big wave, but its far from 1725 feet (525m.) high - its far more likely that the 130 feet of wave being pressed up the small valley will have so much force it will keep climbing up to that level.

    • I was thinking the same thing. Perhaps a more accurate statement would be that this is the highest elevation ever observed on a damage path known to have resulted from a wave?

      From a strict wave height standpoint it would be interesting to try and deduce wave heights for some of the largest recorded meteorite impacts at least partially in water - i.e. impacts that would generate a wave near the impact zone. I'm guessing those would be even more impressive than a mountain side falling off.

    • by Drogo007 ( 923906 ) on Wednesday July 16, 2008 @08:43AM (#24211525)

      If you look at the map of the damage, the 1725 figure comes from the slope directly opposite where the honking huge chunk of rock fell 3000' feet to land in the water - which probably displaced all the water straight up and over the spur where the 1725 figure was recorded and then damage along the rest of the bay was more in line with the 100' figure.

    • by Red Flayer ( 890720 ) on Wednesday July 16, 2008 @09:01AM (#24211839) Journal
      Have you ever seen models of tsunami?

      a 100' wave in 30' of water does not become a 130' wave in 0' of water. This would be equivalent to saying that a 1' wave in 1000' of water becomes a 1001' wave at landfall.

      What happens is that as the water becomes more shallow, the leading edge of the wave slows down, while the deeper water at the back of the wave continues to move quickly. As a result, the wave compresses horizontally, and grows vertically.

      This is similar to what you're saying about the 130' feet of wave being pushed up the valley -- but it's important to note that the wave "being pushed up the valley" to 1725' is the same thing as saying the wave was 1725' high.
  • I think, after reading the article a bit They get that 1720 foot wave from the location directly across the water from the rock slide that stripped vegetation to an elevation of 1720 feet.

    "The spur of land between Gilbert Inlet and Lituya Bay that received the full force of the wave. Trees and soil were stripped away to an elevation of 1720 feet above the surface of Lituya Bay. Photo by D.J. Miller, United States Geological Survey."

    You even get a picture.

  • by xannik ( 534808 ) on Wednesday July 16, 2008 @08:16AM (#24211201)
    This type of tsunami is the exact same as what is predicted will ultimately wipe out most of the Eastern Seaboard. It will make Katrina and even the tsunami that hit in the Indian Ocean look like a cake walk. http://www.guardian.co.uk/uk/2004/aug/10/science.spain [guardian.co.uk]
    • Re: (Score:3, Interesting)

      by pclminion ( 145572 )
      What's really scary about La Palma is that somebody with a hefty nuclear weapon might be able to actually trigger the landslide. If I was a bad guy with a decent sized nuke, I wouldn't waste it trying to sneak it into the US. I'd just blow up the Cubre Vieja fault and let the wave do the work for me. Somebody really should be watching that island.
  • by Azghoul ( 25786 ) on Wednesday July 16, 2008 @08:16AM (#24211203) Homepage

    The photos from the following day are impressive, but I'd like to compare it to what it looks like today: How much has been able to regrow in relatively cold climate in 50 years?

    • Re: (Score:2, Informative)

      by kaptain80 ( 1147495 )
      Here's Latuya Bay in Google Maps [google.com]
    • Re: (Score:3, Informative)

      by DerekLyons ( 302214 )

      'd like to compare it to what it looks like today: How much has been able to regrow in relatively cold climate in 50 years?

      Well, see for yourself [google.com]. :) :)

      Seriously, I've seen a TV program on the 'disaster' and from the ground the you can see where there is an band of young trees around shores of the the bay and older trees further up the slope, but that's about the only visual evidence remaining.

  • I wonder if there were any thoughts at the time relating the tsunami with the russians?

    I mean it was during the cold war and people back then didn't have access to much information as we do now...
  • Splash? (Score:2, Insightful)

    by Anonymous Coward

    At what point do we call something a wave instead of a really friggin huge splash?

  • This comment is nothing to do with the Tsunami, but then neither are most of the others, so I'll risk going Offtopic.
    Firstly, (I'm a Brit by the way) /. is US-centric and as it is American I guess that's fair enough, but as some 40% of /.ers are not, I think a bit of international understanding is called for to stop all this bickering. We all like the same thing (/.) after all.
    Secondly, re measurement, the article, based largely on contemporaneous accounts, used Imperial measures, not metric, so learn to li

  • But... (Score:3, Funny)

    by Bazman ( 4849 ) on Wednesday July 16, 2008 @09:05AM (#24211893) Journal

    Where's the satellite picture of the scene before the earthquake?

  • bad reporting ? (Score:2, Insightful)

    by Tom ( 822 )

    This whole thing sounds like hogwash to me. Not the facts, but the reporting. First, they take the splash damage size as the wave height, even though one sentence later it's acknowledged that wasn't the case. And two, this isn't a Tsunami at all. It's a huge wave, certainly, but it's not a Tsunami. Among other things, you don't notice Tsunamis as huge waves on a boat - that's where the whole name comes from ("big wave at the harbour") - because japanese fishermen came home from the sea, hadn't noticed anyth

  • by meburke ( 736645 ) on Wednesday July 16, 2008 @09:37AM (#24212471)

    OK, when I saw the 1700 ft figure I suspected something was wrong. AFIK, it would take an unbelievable amount of energy to support a mountain of water that high. (Where's frink when I need it?) Even 100 ft indicates a huge amount of energy. It makes total sense if that amount of energy meeting the solidly-planted continental uprising would be re-directed in the direction of least resistance (in this case upslope) until it is dissipated.

    The questions that come to mind are things like: How fast was it traveling? Over what area from the epicenter did it travel? What was the actual water level above ground as it rushed upslope? If I ws on the 5th story of a hotel in the water's path, would I have been able to safely watch? Would the hotel have be able to survive the shock if were made out of concrete? (or sticks? or straw?) How much salt was left behind? (The '64 earthquake dropped the level of Cook Inlet by about 40 feet in some places. [That would be 12.192 meters for those of you who are English-unit challenged.] This caused massive salt-water infusion that killed off vegetation for miles inland on parts of the Kenai Peninsula.) How would I model something like that?

  • It wasn't a tsunami (Score:3, Interesting)

    by mschuyler ( 197441 ) on Wednesday July 16, 2008 @12:49PM (#24216081) Homepage Journal

    I've been to Lituya Bay. I've walked its shores. I managed to lose a crab pot there. I've talked with one of the survivors. Lituya Bay is a protected harbor used by fishing boats to get out of the weather. I used the harbor to protect myself and a 38' fishing boat from 105 mph winds one summer (1967). There is a very narrow passage to get into the harbor. You have to line up to lights (night) or white sticks (day) and traverse between a large sandspit and the shore. In the middle of the bay is an island. It contains ruins of an old French fur trapping venture. At the back of the bay is a glacier. When the earthquake struck a piece of the glacier broke off and entered the bay, quickly, causing a huge wave. The wave rushed away from the back of the bay, washed over the island, and washed several fishing boats over the sandspit into the Gulf of Alaska, snapping their anchor chains easily.

    You can see that this was no ordinary 'tsunami.' The wave did not come from the sea, but from the shore and moved outward. take a look on Google Earth and you will see what I mean. 58*37'52" North, 137*36'03" East.

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