Discussion of paper by V. I. Keylis-Borok and L. N. Malinovskaya, ‘One regularity in the occurrence of strong earthquakes’

Abstract

The observation of general increase in the seismic activity of an area for an extended period before a major event has been reported on a number of occasions. Well-known examples are those associated with the great earthquakes in Japan in 1891 and 1923. The authors have made a creditable effort to convert this rather indefinite and elusive phenomenon into a precisely definable one. It is important that they confirm the necessity of considering a very extensive region including the center of the approaching event. It is very rarely true that a major event is preceded by increasing activity in its immediate vicinity. Such a claim was made by Davison for the Japanese occurrence of 1891; critical reading suggests that he overlooked many details and misinterpreted the data.