For about twenty-five centuries observations have been made of a great number of possible precursory phenomena of seismic events, and related data have been gathered and recorded by observers, whether professional, casual, or indirect. During the last 120 years such data have been collected more systematically; they have become the object of prediction-oriented applied research during the last thirty years, in conjunction with a better understanding of the physical and chemical phenomena which accompany earthquake occurrences. The main ways in which concepts about earthquakes, earthquake precursors, and earthquake prediction research have spread in space and time have been reconstructed. The constraining scientific and economic factors that have caused acceleration or retardation in seismic precursor research have been considered and commented upon.

You do not currently have access to this article.