Can't tell or foretell

Published: Sunday 31 August 1997

earthquakes do not follow predictions. A conclusion that has long been reached by other countries and only now accepted by Japan. The country's earthquake-prediction programme, the last in the world, with an annual budget of us $145 million is about to close down. A report accepted by the ministry of education's Geodesy Council finally admits that their programme is a complete failure. The Council is now asking the government to divert the resources into constructing safer buildings. With the Japanese capital sitting over the junction of the Earth's three tectonic plates, it was hoped that the earthquake-prediction programme will detect any abnormal precursor phenomena -- bulging of the Earth's crust, variations in its electrical resistance and in the local magnetic field, and changes in the level and chemical composition of ground water among others.

For instance, seismologists in California had noticed that a section of the San Andreas fault near the town of Parkfield tended to slip every 20 years generating a magnitude 6 earthquake. They confidently predicted another earthquake before 1993. In Japan, it was predicted that the shock which killed 142,000 people in the greater Tokyo area in 1923 was one in a series of quakes that occur every 69 years or so. But fortunately, for the residents of Parkfield and Tokyo and unfortunately for the scientists involved in earthquake prediction, both these shocks have not yet occurred. However, the Kobe earthquake in 1995 in Japan, which killed 6,400 people quite escaped the notice of the seismologists.

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