The mirage of prediction

The ongoing debate about predicting tsunamis is a pseudo-scientific obsession with no basis in fact

Sankar Ray Delhi

Seismologists, geophysicists, oceanographers and geologists continue to be stupefied by the recent mega-seaquake in the remote outreaches of the Indonesian archipelago. Benjamin Fong Chao of the Goddard Space Flight Centre of the US National Aeronautical and Space Administration (NASA) says, "The Earth got hit pretty hard on December 26. For the first time, we hope to see the effect of an earthquake, but it will take a couple of months to sort through the data." And this comes after he scanned reams of seismological data along with Richard Gross of NASA's Jet Propulsion Laboratory.

But journalists are journalists — know-it-alls: one of them wrote, with scholastic pretension, in a prestigious Mumbai-based weekly that tsunamis in the Bay of Bengal region have a roughly 60-year periodicity (1881, 1941, and now 2004). He wasn't so different from the political pundits who, in 1980, said that political crisis would erupt in Poland at 12-year intervals. Did anything happen in and around Warsaw in 1992 or 2004? Nope.

The price of being blissfully aware about such a rich literature on the "seismic gap theory" is ominous, indeed. Experts at the Pacific Tsunami Warning Centre (PTWC) in Honolulu, operated by the National Oceanographic and Atmospheric Administration (NOAA), stated unambiguously that tsunamis were rare in the Indian Ocean and that no system was known that could detect them and send out alerts (“No Warning At Warning Center” by Michele Kayal and Matthew L Wald, The New York Times, December 28, 2004). The authors, themselves oceanographers, admitted two problems in identifying the seaquake in the Indian Ocean and alerting potential victims. "There is no direct connection between an earthquake magnitude and a resulting tsunami," they wrote. "Not all quakes under the ocean lift the ocean floor to displace the water needed to create a tsunami."

D R Nandy, former director of the Geological Survey of India (GSI), who worked for nearly three decades on geo-environment, including earthquakes, warns against obsession with prediction. "Will Durant's coinage 'geological consent' is significant," he says. "Of about 4.08 million victims of natural disasters between 1900 and 1988, 85 per cent were killed in Asia and the Southwest Pacific region. The poor, mostly the abject poor, are chiefly vulnerable to natural catastrophes. Their ignorance and illiteracy, living habits, etc, push them to tragedies. They aren't mentally or physically prepared to confront mega-disasters. I raised this point at a seminar on disaster management in 1999 at Jadavpur University [Kolkata]. I have been talking of micro-zonation and rehabilitation thereof, based on vulnerability index to give the poor a hedge against earthquakes and more than half of India is seismic. When we can't prevent them we must learn how to live with them, instead of foolishly interfering with the 'playground' of nature."

One of the very few specialists on seismic hazards, Nandy questions the reliability of predictions. In a paper, "Neotectonism and seismic hazards in India" (Indian Journal of Geology, Vol 67, 1995), he suggested estimation of "return period" in "seismogenic faults in western Gujarat", citing earthquakes in Bhuj, Anjar and adjoining areas in 1919 and 1956, but categorically said — when his attention was drawn to the paper — "I refrained from forecasting a major earthquake. The Chinese hazards analysts who link strange behaviour of animals as precursor to quakes got it right in 1975 but failed in 1976. Let's not chase the mirage of prediction."

Unfortunately, some scientists aren't talking sense, either. Even President A P J Abdul Kalam, a man of solid scientific temper, said in his D S Kothari Memorial Lecture on December 31, 2004, "In certain countries, earthquakes have been successfully predicted using a noticeable increase in background seismic activities. If foreshocks can be recognised early, giving a timely warning can save lives of many people." The President has, however, never worked in this area.

Philip L F Liu, Cornell professor of civil and environmental engineering, wrote in an article in Science (October 1997), "From locations all around the Pacific, we cannot now predict what kind of tsunamis form, where they are from, and how to accurately gauge their magnitude." Brimming with optimism, he said that with a network of underwater sensors, "we can start to research tsunamis and perhaps we'll be able to save lives".

The problem is that the much-vaunted PTWC has also frequently failed to predict tsunamis. Despite crowing about its abilities post-tsunami, it has even been known to issue false alarms. That's par for the course — disaster prediction is built on a plinth of baloney.