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Introduction

Since World War II, scientists have greatly increased their knowledge about the Earth's crust. That knowledge has led directly to a better understanding of why earthquakes happen. Now most seismologists and geologists are confident about the accuracy of their long-term earthquake predictions. But they have had much less success with their short-term predictions.

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Overview

The 1970s were heady days for seismologists, geologists and geophysicists. They were convinced that it was possible to predict the time, place and magnitude of at least some earthquakes. American scientists, encouraged by several accurate predictions overseas, eagerly exchanged information with their Japanese. Chinese and Soviet colleagues at international conferences and then rushed to the field to try out new approaches. On Aug. 2, 1973, Yash P. Aggarwal, at the time a graduate student at Columbia University, accurately forecast a small earthquake in the Adirondack Mountains of New York state. Other successful earthquake predictions followed. A breakthrough seemed imminent—so near, in fact, that in 1975, one prominent geophysicist said that “prediction within a decade [is] a realistic goal.”

Thirteen years later, however, scientists still aren't able to make accurate, short-term predictions of earthquakes. Frank Press, president of the National Academy of Sciences in Washington, D.C., sums up the lack of progress this way: “Some of the ideas that we had in the 1970s didn't pan out….I don't think anybody would claim that we have either a long-term or a short-term prediction capacity, except in probabilistic terms….There have been some successful short-term predictions in China, but the techniques when applied elsewhere have failed.”