Tsunamis and earthquakes, wisdom ancient, modern, and dubious

 
"Always be prepared for unexpected tsunamis. Choose life over your possessions and valuables."

So reads an inscription on one of the ancient tsunami stones that dot the hillsides of Eastern Japan. Others bear messages such as “Beware the calamities of the great tsunamis,” and "If an earthquake comes, beware of tsunamis"; the two meter stone on which the latter wisdom was written was washed away by the tsunami of the 11th March. These stones can be hundreds of years old and can be found – worth taking note of this, you would think – high on hillsides and far inland from the coast.

It’s been a while since I fulminated about ignoring tsunami records, citing the historical and geological evidence that unambiguously showed that an event on the scale of the March catastrophe fell into what should be the “expected” category; more evidence has emerged in the meantime, more informed voices of reason have spoken out, but, alas, the idiocy continues. If we can’t take note of warnings from just a few generations ago, never mind science, what hope is there? Just what exactly is our attention span and how do we set our priorities? Well, the answer to the first question would seem to be about three generations. Andy Revkin, of the New York Times, recently wrote a couple of pieces that are well-worth a read and a follow-up of the links -  Limits to ‘Disaster Memory,’ Even Etched in Stone and ‘Disaster Memory’ and the Flooding of Fukushima. Fumihiko Imamura, a professor in disaster planning at Tohoku University in Sendai, a tsunami-hit city, observes that "It takes about three generations for people to forget. Those that experience the disaster themselves pass it to their children and their grandchildren, but then the memory fades." An obvious question, it would seem, at least to me, would be the extent to which dimensions of today’s society (politics, technology, the media, and greed spring to mind) perhaps accelerate the loss of “disaster memory.”

The rhetoric of the tsunami stones is straightforward, empirical, and pragmatic. But sadly these terms can hardly be applied to the rhetoric of today. In spite of the ancient advice to “always be prepared for unexpected tsunamis,” the nuclear authorities and operators in Japan continue to express their surprise. And, while I am an avid reader of the New Scientist, I know that I am not alone in feeling that, in recent years, its content has had to be increasingly scrutinised for statements that, shall we say, depart from scientific and objective rigour. Some of this originates from gently grinding editorial axes, some from quoting sources without checking the accuracy. For an unfortunate (and surprising) example of the latter, here’s a quote from a March article titled Seismic zones shake out nuclear problems, in which John Stevenson of the International Seismic Safety Centre of the International Atomic Energy Authority is quoted as describing how “nuclear energy authorities will want to re-examine the potential for tsunami risks to nuclear power plants,” and continues:

While power companies already estimate the risk from tsunamis based on the geological record, Stevenson admits that “there is always the chance that what has been experienced in the past will be exceeded.”

I simply don’t know where to start on this – the entire thing is erroneous and absurd from start to finish. Perhaps I should start by re-reading my earlier posts. But perhaps it’s also worth pointing out that Stevenson had clearly never heard of (or at least paid no attention to), Masanobu Shishikura. Dr. Shishikura, a geologist, works at the Active Fault and Earthquake Research Center in Tsukuba, a government-funded institute; a Wall Street Journal article earlier this month had the following:

The Man Who Predicted the Tsunami

After studying ancient rocks, a Japanese geologist warned that a disaster was imminent—to no avail

By PETER LANDERS

The giant tsunami that assaulted northern Japan's coast surprised just about everyone. But Masanobu Shishikura was expecting it. The thought that came to mind, he says, was "yappari," a Japanese word meaning roughly, "Sure enough, it happened."

Yes, he was one of the geologists analysing tsunami sands, in this case those from both historical events and those from thousands of years ago; I referred to some of this work in my first post on this subject. He and his colleagues had published their results and the work was brought to the attention of the authorities; Dr. Shishikura had an appointment on March 23 to explain his research to officials in Fukushima. But, a couple of weeks before, yappari. 

The failure of “disaster memory” and the consequences of ignoring the science apply to the earthquake itself, as well as the tsunami. In Nature, Robert J. Geller of the Department of Earth and Planetary Science, the Graduate School of Science at the University of Tokyo, wrote a fascinating piece a couple of weeks ago titled Shake-up time for Japanese seismology; here’s the introduction:

Robert J. Geller calls on Japan to stop using flawed methods for long-term forecasts and to scrap its system for trying to predict the 'Tokai earthquake'.

Globally, in the past 100 years, there have been five subduction-zone earthquakes of magnitude 9 or greater (Kamchatka 1952, Chile 1960, Alaska 1964, Sumatra 2004, Tohoku 2011), which suggests that the upper limit on the possible size of a subduction-zone earthquake may not much depend on the details of the subduction modality. Large tsunamis have frequently struck the Pacific coast of the Tohoku district. The well-documented 1896 Sanriku tsunami had a maximum height of 38 metres and caused more than 22,000 deaths. The 869 Jogan tsunami is documented to have had a height roughly comparable to, or perhaps slightly less than, that of the 11 March tsunami.

If global seismicity and the historical record in Tohoku had been used as the basis for estimating seismic hazards, the 11 March Tohoku earthquake could easily have been 'foreseen' in a general way, although not of course its particular time, epicentre or magnitude. Countermeasures for dealing with such events could and should have been incorporated in the initial design of the Fukushima nuclear power plants.

Geller describes the bizarre and idiosyncratic way in which a generic but named earthquake (“Tokai”) was essentially the basis for all disaster planning and legislation, effectively dislocating the process from reality and the scientific evidence.

This is rational and evidence-based – rather like the declarations of the tsunami stones. But when it comes to describing the seismic event, we seem to have abandoned all temperance. Which brings me again, unfortunately, to the New Scientist. How do you like this for a headline in a serious scientific publication?

“Starburst megaquake: Japan quake overturns geology.”

The article begins as follows:

THE Tohoku earthquake that rocked Japan last month has sent geologists reeling. As the first analyses of what may well become the best studied earthquake in history start to filter through, there is already talk of rewriting the rule book on how "megathrust" quakes happen.

Yes, the event was, literally, extraordinary (but not unprecedented) – in magnitude, in the nature and complexity of the rupture, in the frequency and location of aftershocks; sure, the sheer volume of data collected in association with the earthquake and its aftershocks is unprecedented, and major revisions to our understanding of such events will inevitably result, along with the abandonment of some cherished hypotheses and models.  But “ sent geologists reeling,” floundering about in their overturned science by a “starburst megaquake”? Please, give us all a break.

And then there is the excitement – and newsworthiness in the “be afraid, be very afraid” category – of the idea that large magnitude earthquakes are connected, that the Japanese event was an aftershock of Sumatra, and so on and so on. Contributing to the smoke and dust around this idea was Simon Winchester, whose cataclysmic declarations have been thoroughly and thoughtfully dismantled by (amongst others) Chris Rowan in “How to (and how not to) talk about earthquake hazards in the media.” Our friends at the New Scientist declared that “discussions over the clustering of megaquakes will rumble on” after describing how workers at the USGS and the University of Texas had reviewed a 30-year catalogue of events and found “no significant evidence  that large quakes regularly trigger tectonic activity 1000 kilometres or more away.” And, as Ross Stein of the USGS was quoted as saying (in the same article), “You will get a lot of different answers from different people, but inevitably the ability of any one of those to convince everyone else that they’re right is going to depend on the statistics of very small numbers, and we’re never going to get anywhere.”

I was struck by many of the things Stein has to say, but I like this in particular (for obvious reasons), further discussing the idea of triggered events:

If you have a quake of, let’s say 6.2 or larger, every sand grain on the planet is moving to the music of that event 

I think that I’ll end this rant with that poetic side of science.

Comments

[F]

*Standing ovation*

In the U.S., people forget about the hazards of living where they do on a yearly basis, never mind having regard for "natural disasters" on a longer time scale. Major earthquake? Rebuild the city in the same spot, what?

[Richard Bready]

Three generations: my parents grew up amid the Great Depression (like "The Great War," we should perhaps now rather call that Depression One). They taught their baby-boom children the reality of economic disaster and political instability. Their grandchilden heard instead on all sides about The New Economy and The End of History, companies and countries Too Big To Fail. Yappari.
Sorry to hear about New Scientist. Auden advises would-be poets, "Read The New Yorker. Take short views." Not what science is about, and that's what makes science journalism so difficult and valuable, when it's good.