A Seismological Retrospective of the Brady-Spence Prediction

Abstract

In the annals of earthquake prediction research a small handful of specific predictions are notable by virtue of their impact in scientific and/or societal circles. Of these, the so-called Brady-Spence prediction that a large earthquake would strike Peru in 1981 stands out both for having been put forward by members of the mainstream earthquake science community and for having generated significant repercussions in the international arena. A well researched book-length retrospective was published in 1989 (Olson et al. 1989). This book considers the reaction to this prediction from a social science perspective. The lead author is a political scientist; two co-authors are also social scientists. Olson et al. (1989) conclude that the scientific community's response to the prediction serves as an example of the hostile reaction that Kuhn (1962) observes to be frequently engendered by scientific research that challenges existing paradigms. For the scientists involved with evaluation of the Brady-Spence prediction, the episode was generally viewed as an unpleasant exercise, best forgotten. Perhaps as a consequence, a retrospective of the prediction from a scientific perspective has never been published. The purpose of this report is to rectify that. Although it came to be known as the Brady-Spence prediction, the prediction was primarily the brainchild of Brian Brady, a geophysicist who had earned a PhD in geophysics from the Colorado School of Mines and in the 1970s worked at the United States Bureau of Mines, where his research focused on rock bursts in mines. Founded in 1910, the USBM was for years at the forefront of research in the minerals and mining fields. In September 1995 the Bureau of Mines was closed; the bureau's minerals information functions were transferred to the U.S. Geological Survey. By the mid-1970s, when Brady began to formulate his prediction, the agency's fortunes were in decline; in …