Cannot Earthquakes be Predicted?

Wyss, Max; Aceves, Richard; Park, Stephen; Geller, Robert; Jackson, David; Kagan, Yan; Mulargia, Francesco

Robert J. Geller et al. are on shaky ground when they state, in the title of their Perspective (1), that earthquakes cannot be predicted. In spite of their advice, we should not stop studying the physics of preparation for catastrophic rupture, in the held, the laboratory, and theoretically; neither should we stop measuring crustal parameters that might furnish constraints for physical models; and we should continue researching statistical methods to evaluate prediction claims and to test hypotheses quantitatively. Some of the arguments Geller et al. put forward are incorrect. For example, the 'slip on geological faults' is not always as 'sudden' as they state. In 10% to 30% of large earthquakes, foreshocks occur days (2) to months (3) before the main shock. Seismologists agree that foreshocks are a symptom of some preparatory process to the main rupture. Thus, foreshocks are precursors. If that process could be detected and understood by measuring the several physical parameters of Earth's crust that probably change during it then prediction would be possible, even if foreshocks themselves can be identified with a low probability only (4). When Geller et al. state that '[t]here are no objective definitions of 'anomalies'' and that 'statistical evidence for a correlation is lacking,' they appear to be referring to specific papers that have been criticized (5). However, there are examples of clearly formulated, even tested, hypotheses. Evison and Rhoades (6) formulated a rigorous statistical test and applied it in real time to their well-defined hypothesis of precursory earthquake swarms. The algorithm M8 (7) has been tested in real time, and critically evaluated by others (8). The hypothesis of precursory quiescence also has been clearly stated (9), and specific predictions have been made to test it (10). On the basis of a mathematical model of failure of earth materials, the hypothesis of increasing moment release has been formulated (11) and tested by predictions (12). Geller et al. are also incorrect in stating that 'no quantitative physical mechanism links the alleged precursors to earthquakes.' Geller et al. are again incorrect when they say that 'the leading seismological authorities of each era have generally concluded that earthquake prediction is not feasible.' Geller et al. state that they believe that earthquakes occur at random. The figure in the Perspective by Geller et al. (p. 1617) does not support the idea that earthquakes are unpredictable. At the time of Columbus, most experts asserted that one could not reach India by sailing from Europe to the west and that funds should not be wasted on such a folly. Geller et al. make a similar mistake, but I doubt that human curiosity and ingenuity can be prevented in the long run from exploring fully the extent to which at least some earthquakes are predictable, although it is not easy. Such discoveries will be made in Japan, Europe, or China if the current lack of funding for earthquake prediction research continues in the United States

Cannot Earthquakes be Predicted?

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