Sunday, December 26, 2004

The Asian Earthquake

The Earthquake in Southeastern Asia is, first of all, a sad event for the people there, and it is sad for all of us. Tens of thousands of lives were suddenly ended by evil, despicable acts of mother Nature.
The earthquake (8.9) was the strongest one since the 1964 tremor in Alaska, and the fifth strongest in the last 100 years. (Note that the average period is 20 years, so we've had a rather long period between two large earthquakes.) It came exactly 1 year after the quake that destroyed the Iranian city of Bam. Because the center of the earthquake was just below the surface of the ocean, it generated massive waves, the tsunamis. Well, some other sources claim that it was 10 kilometers below the sea level, but there are many other contradicting news, too.

I always wondered whether it's possible to escape from these tsunamis. But it's not realistic. The waves on the ocean have very different dispersion relations from the electromagnetic waves, for example. More precisely, the speed increases with the size of the waves. (Well, it's not just about the dispersion relations because the waves behave non-linearly as a function of their amplitude.) The ideal approximation of tsunami is the so-called "shallow-water wave" in which the speed is sqrt(g.d) where d is the water depth.

It just happens that these waves that can be as high as 10 meters propagate with the speed about 300 miles per hour - something like 120 meters per second. Now if you're enjoying the Sun on the beach, you only see the wave when it's one mile away or so, and therefore you have something like 10 seconds to run. It's very hard to run in the sand, so perhaps it's better to give up immediately. You just can't escape from a wave which is 10 meters in height unless you are a highly intelligent squirrel that can quickly climb a sufficiently massive tree or unless you see a staircase nearby. Well, what I just wrote is not quite true because the waves usually slow down to about 30 miles per hour when they approach the land, because of the dependence on the water depth mentioned previously, and therefore you can actually have a minute to leave...

There are also some warning systems (one still has a few hours before the wave reaches the shores), but unfortunately they were not used in this case: tsunami are not too frequent in this are and the people are too poor to organize some high-tech security systems. Tsunami means "wave in port" or "harbor wave" in Japanese.

28 comments:

  1. A couple of points - the high velocity of the tsunamis is due to their long wavelength (about 10 km), not their great amplitude, which is not necessarily larger than ordinary beach waves. Also, although they travel very fast, they are still more than an order of magnitude slower than seismic waves, so an automatic detection, prediction, and notification network could likely save all but the most promimate from the effects.

    A nice discussion of the physics can be found in this article.

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  2. Yes, tsunami warnings were in principle possible for India, Sri Lanka, Maldives, etc. for the event yesterday. Tsunamis are rather rare though, in the Indian Ocean, the last incident to hit India was in 1941, apparently. Given a lead time of perhaps a couple of hours, the population has to be prepared to receive warnings as well. Perhaps it can be built as part of a cyclone-warning-evacuation system; cyclones (hurricanes) are virtually annual events.

    Apparently the west coast of the US, Japan, Hawaii, etc., have warning systems in place - tsunamis are much more frequent in the Pacific.

    There was an 8.1 magnitude earthquake in the South Pacific on Dec 23
    (), and going by this list it was a significant earthquake in size; but perhaps with no effects on human populations.

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  3. It is certainly true that from the perspective of someone sitting at the beach, a Tsunami is recognizable only within the last minute of the observer's life span. It is even true that from the much safer perspective of an air plane a Tsunami becomes only apparent when it destroys a coast line. This is so because of the huge ratios of wave length to amplitude, which are typical for Tsunamis. In the limit of such large ratios, the waves apparently become almost solitonic. This allows them to travel distances between continents with ease. Here is a computer generated animation, that shows an actual Tsunami in the 60s -- triggered by a land slide, it crossed the entire Pacific and caused vast destruction:

    http://www.geophys.washington.edu/tsunami/movies/globe.mov

    Look how a Tsunami makes oceans look like bath tubs! It's amazing.

    In fact some scientists are quite worried that volcanic islands in the eastern atlantic might cause Tsunamis that could destroy large cities like Boston or NYC.

    I personally do not know how likely such a scenario is and I despise alarmists (climate or otherwise). But after initially being oversceptical I have convinced myself that a large landslide, say, at the Western European coast line *could* destroy a city like Boston. I guess it might make sense to have geologists assess where risk spots are and how they could be defused before anything happens.

    Best,
    John

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  4. Thanks for your interesting comments! And yes, John, I also think that the geologists should be working on such things seriously - and every geologist should try to have some qualified opinion about these matters and probabilities...

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  5. Eyewitness account:

    http://www.alertnet.org/thenews/newsdesk/DEL145878.htm

    Quotes:

    "Never in my life I have had such an experience. The whole area has been turned into a cemetery," said Chellappa, a 55-year-old fishermen in Madras.

    "I was standing by the seashore when I noticed the sea level rising but I was not concerned then because I only thought it was an unusually high tide," said Chellappa.

    "Then I heard an eerie sound that I have never heard before. It was a high pitched sound followed by a deafening roar which seemed to be getting louder. I told everyone to run for their life and I started sprinting inland."

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  6. Concerning the monitoring and warnings - sure, this is what would be done in the West. But I am skeptical about these less developed places. If something only occurs once per several decades, you're not gonna create a special system of mechanisms to warn and save people - it just does not fit a poor economy. Unfortunately. If these places were colonies, it could be very different.

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  7. The video is really amazing - is not it just some idealized friction-neglecting simplified calculation? May we trust it?

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  8. Lubos, occasionally you descend into the worst bullsh**. India has seen any kind of public health and disaster mitigation efforts only after Independence in 1947. The best indication of the effect of being a colony of the West is to study the life-expectancy and population growth figures before and post-Independence of any country unfortunately enough to be colonized.

    When the British left India, the life-expectancy at birth was around 32 years.

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  9. Well, Arun, you only see one side of the coin. Maybe a few more earthquakes will change your mind.

    You know that there are earthquakes in California, too, but for a mysterious reason they don't kill 10,000 people.

    Best
    Lubos

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  10. lumo: ...If these places were colonies, it could be very different.So am I to understand that the Czechs thrived under Russian colonialism?

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  11. Sorry, pig, but Czechoslovakia was never a Russian colony. And there were times when this independence was actually a very negative thing. When Gorbachev took over the Soviet Union in 1985, the neostalinist aparatchiks remained in power in Czechoslovakia, without any ability of Moscow to change anything.

    What we hate was the occupation in 1968. But it was not colonialism in any sense. We had to have our own communists who just took over - they were supported a bit. The Czechs and the Russians are Slavic nations, and we viewed each other as friends in a sense. The closest friends in the Soviet bloc, if you wish, which is why, for example, Vladimir Remek became the first non-US non-USSR astronaut. Despite my negativity about the communism, I am still grateful to the Red Army for liberating us from the Nazis.

    Incidentally, under the Nazis we were a "protectorate" which is rather close to being a colony, but this regime was not my main objection against the Nazis either. Of course I would be revolting against them, but on the other hand, the war period in Czechia was also a rather cultural and prosperous era, if you view it economically.

    If you were trying to induce my negative emotions against colonialism, you may look into Austria-Hungary. But it was no disaster either. It was just risky for the Czech culture that could evaporate.

    You know, I am a clear Czech patriot, but a realistic one. I realize very well that the Czechs don't necessarily control their fates in a better way than someone else. The first Czechoslovak republic was one of the great examples in which the Czechs and Slovaks themselves were leading their country in the right direction. On the other hand, the communism afterwards was not really imported. It was unfortunately a free decision of most of the Czechoslovak nation to establish this bad system.

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  12. "If these places were colonies, it could be very different.
    "
    I have often noticed that people from central and eastern europe are very often prejudiced against asians. Is it some survival of the old "yellow peril" syndrome?

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  13. Dear last contributor,

    this has nothing to do with the race. It is an objective comparison of GDP per capita in different regions of the world. If you need it, I will give you some tables.

    I view Asia as one of the cradles of human civilization. And incidentally, I am very happy about the retailers from Vietnam who sell a lot of stuff on the Czech streets simply because they have good prices. ;-)

    All the best
    Lubos

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  14. Hmm a (would-be) bostonian can not be surely opting for a colonial system, can him? So perhaps you are pointing out that a British control of the southern seas would for sure take all the guarantees to keep the metropolitan commertial benefits, and such measures would include a Tsunami Alert System. I agree, but I doubt that the civil population were alerted and evacuated. But yes, tourists would be safer.

    On other hand, if the Tsunami originates in a French or Holland controlled sea, perhaps some "communication problems" could arise when alerting the british colonies.

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  15. Surely you don't believe that I would care a single bit about some entertaining rivalry between the British and the new Americans in the 18th century.

    For me, history (of the American independence, in this case) is just kind of fun. Everytime I hear some explanations how they had to fight against the evil Englishmen (with the crazy king whoever he was) who wanted them to pay high taxes etc. :-), I fully sympathize with the American approach but it's a lot of fun simply because the difference between England and America is so small.

    Don't get me wrong. I admire the American founding fathers. In my opinion, they were the most intelligent and realistic leaders of any revolution that took place anywhere in this world.

    On the other side, they were biologically British. Most of the good things about the current American system - including the legal system - was just taken (or stolen, if you wish) - from the British. There is still the Anglo-Saxon world, despite the independence.

    I have no idea how America would look like if it continued to be a British colony, but my guess is that it would not be too different.

    I believe that if the (Asian) colonies continued today, with the technology available today, the population would no doubt be alerted by the British officials. France or Holland could want something for alerting them, but it's reasonable to guess that they would alert one another, just like they do it in real Europe today. Don't overestimate the rivalry.

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  16. this has nothing to do with the race. It is an objective comparison of GDP per capita in different regions of the world. If you need it, I will give you some tables.

    So you Czechs had better start learning Japanese, since the standard of living there is vastly higher. Are you ready to start bowing to your new colonial overlords, Motl-san? Have you contacted the Czech government asking them to submit to a Greater East European Co-Prosperity Sphere?

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  17. You will be surprised, but the Czechs have really had a lot of respect to the Japanese, especially on the technological front. This is not about learning Japanese language - I've never written something like that. (The people in the colonies kept their language, and if they also learned English, good for them!) It is about hiring them to control and supervise your security systems, under some economic conditions.

    I am sure that most Czechs would have been happy to ask Japanese to take care of such issues, at least a couple of years ago.

    But today, the standard of living is certainly not "vaster" higher in Japan than it is in Czechia. You may be surprised, but the Czechs' standard of living is now at 73 percent of the European Union's average, and there are aspects in which the Czechs' standards are simply higher than the Japanese ones. There's not much difference to justify Japanese-controlled programs, but if the difference were higher, of course that the Japanese support/leadership in some issues would be a very intriguing choice.

    This has really nothing to do with the race, and on the other hand, the technological and economical standards of the individual countries are very important if you talk about the security and prevention of the disasters. I am not sure why you don't want to admit it.

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  18. "the technological and economical standards of the individual countries are very important if you talk about the security and prevention of the disasters."

    Lubos,

    Perhaps you realise that with almost all Asian colonies, the technological and economic standards improved vastly after the colonists left? Of course in some places it improved faster than others. Also, India has not suffered a famine since independence, but suffered several under our British overlords?

    Or perhaps you prefer not to let facts get in the way of your opinions?

    Vish

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  19. Vish, that's ridiculous. A reasonable analyst would compare the countries at the same time, not at different centuries.

    Famines decreased because the whole world has become richer and more advanced. We used to have famines and various widespread diseases in Bohemia as well, several centuries ago, and they disappeared because the food production and quality simply became better. It has nothing to do with colonialism or who is in charge, and if you're making these strange causal connections between the events, you're still using a cargo cult science approach. If there are many people in Southeastern Asia using this "West is Evil" approach to particular questions, then I don't predict too a bright future for that region.

    You know that South Africa was probably the most strongly colonized country in Africa where the colonists became most powerful, and it is also perhaps the most developed one. Sorry if it violates some of your prejudices, but it is the case.

    One more thing. Judging by your comments about the famines, your knowledge of Indian history seems to be rather poor. You should know that it was 1668 when Britain took over Bombay, India, and gave Bombay to the East India Company the same year. However already in 1630-31, which is 37 years earlier, there was a great famine in India. Records indicate that cannibalism became so rampant that human flesh was sold on the open market. (SFC, 7/6/96, p.E4) You don't want to claim that in 1630, India was controlled by Britain, do you? Have you heard of Shah Jahan? There was just a lot of trade at that time, much like today, and if you oppose trade, well...

    Also, in 1966, 17 years after the independence of India, there was a rather large famine in India that was only stopped because the USA allocated 900,000 tons of grains for India.

    A major famine during the colonial times was in 1943, Bengal, but it was war so you can't expect too much attention from Britain.

    See http://timelines.ws/countries/INDIA_A.HTML for some basic points of Indian history. Even though I am not British or American in any sense, I find your interpretation of Indian history insulting.

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  20. Lubos,

    You know nothing of famines. Famines are always the result of government inaction in the face of local crop failures. eg. Ireland 1800's, China 1960, India several times - but none after it became a democracy in 1947. This has nothing watsoever to do with general economic progress, but entirely due to the fact that the Indian government has to face elections in 5 years, unlike the British Raj.

    If you really believe that an unelected dictatorship
    by foreign rulers is superior to elected democracies (even ones that for 4 decades were clinded by socialist thought), I am surprised.

    Vish

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  21. Lubos,

    Also, note that no tsunami early warning system exists in the Atlantic Ocean - where Tsunamis are about as common as in the Indian Ocean (ie, very, very rare).

    If I were you (ie, on the Atlantic Coast), I might be worried.

    Vish

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  22. Sorry, Vish, but I find your politicization of all these issues highly obnoxious.

    Let me tell you what a famine is:

    http://en.wikipedia.org/wiki/Famine

    A famine is an phenomenon in which a large percentage of the population of a region or country are undernourished and death by starvation becomes increasingly common.

    I've also explained you that your data about India after 1949 are corrupt - or lies, if you wish. The only reason why famine in December 1966 did not become the biggest disaster in Indian history was that the USA allocated 900,000 tons of grain for India. India would be absolutely screwed without the help of the West in the 1960s.

    Maybe, when you're showing that your not grateful at all, and maybe even negatively grateful, perhaps America and others should become less active this time and next time, and let Nature do its natural job?

    It's also very irritating to read about the "government inaction". I am sorry but the task to eat and find food is primarily a personal task for every individual and every family, and in capitalism it is a job expected to be done by the agriculture and food industry, and the task of every individual is to find the providers of food and make the right deals. Do you want me to teach you to eat? ;-) If there is somewhere a large group (or even a whole nation) of people that wants to rely on the "government" to feed it, then I apologize, but I consider a famine among this group of people a less serious problem than an average famine.

    You're also lying if you call the British rulers an "unelected dictatorship". Britain has been a democracy for quite many centuries. I am not saying that the leadership of enlightened foreign leaders is better in all respects and under any circumstances; in this particular case I just mentioned that it would definitely have made the security situation much more plausible and the ability to deal with the aftermath of the quake would be higher. Common sense is enough to understand why what I say is obviously true.

    In the past, the people from the colonies etc. had limited human rights. This is simply the logic that was commonplace at that time. Two thousand years ago, slavery was a standard. Today it's different and people are generally treated as equal by all advanced countries, and this would most likely apply to India if it were a colony. It's been a rather natural development.

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  23. I am ready to make a bet with you that there will be no tsunami in the next 20 years that will kill more than 50,000 people on the Northern hemisphere's Atlantic beaches.

    Your comparisons of Asia with the Western security against natural disasters are totally ludicrous. Exactly one year before the Indian quake, there was an 6.6 earthquake in Iran, 30,000 dead in Bam. Comparable quakes in the West have no fatalities.

    The higher 9.2 Earthquake in Alaska 40 years ago had 100 fatalities or so, and so forth. Do you really want to question that lower casualties are expected - and seen - for more solid buildings and other structures, as seen in the West?

    This is a completely silly discussion. The security system in America goes that far that they're developing the Missile Defense System. It's not chosen just for fun - it's because the country has been more or less secured against all imaginable threats.

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  24. Lubos,

    I have lost track of what you are arguing. You say that Western Developed nations have better systems in place to prevent natural disasters - uncontestable. And you attribute the poverty of the same systems in South Asia to the fact that they are no longer colonies?

    Vish

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  25. Regarding famines - I suggest you read Amartya Sen's "Poverty and Famines". He is no left-wing economist, and he clearly describes how and why famines occur.

    One of his points is simply that democratic regimes are forced to respond to famines and do so (even if the response is begging, as in the 1960's). Unelected regimes (like the British Raj in India, or China during the 1950's) did not care to do so.

    Vish

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  26. Hi Vish!

    You're blowing this topic to higher scales than necessary. This was originally about the security systems to warn about tsunami.

    I think that the earthquake is very sad and big and the world must help, and I am sure that the colonists if there were any would be much more generous than the "other" nations will be today and tomorrow. It's based on many observations - for example look how West Germany flooded East Germany with money - too much actually, and it was not quite productive.

    It would be oversimplified to state that someone is poor because he's not a colony anymore, but it would be even more misleading to argue that someone is richer because he's not a colony anymore.

    Happy New Year
    Lubos

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  27. "I am ready to make a bet with you that there will be no tsunami in the next 20 years that will kill more than 50,000 people on the Northern hemisphere's Atlantic beaches.
    "
    I am willing to bet that if a large tsunami approaches New York or Boston, everyone will be warned far in advance. The result will be that everyone will pile into their SUVs and die in the largest traffic jam in history. But at least they will have the consolation of knowing that they died in a rich country....

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  28. It's pretty hard to make bets with anonymous contributors who, moreover, don't indicate that there is much chance that they would be able to meet with you at the end of the bet period.

    The traffic jam is unrealistic. In Boston, a tsunami like the Indian one would definitely not force the whole of Boston to immediately evacuate. It would be just an amount of people that is so much smaller than the number of cars that normally leave the city that you would barely see a difference.

    And there are cars in the USA besides SUVs. ;-)

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