47 Historical seismology: the long memory of the inhabited world

Abstract

Historical data provides valuable information about the size and frequency of past earthquakes, thus contributing to the formulation of seismic hazard and risk estimates and the location of active faults—especially where particular geological complications make their identification difficult. Historical seismology uses historical data to identify the effects of past earthquakes and to explore specific seismological questions such as when, where, and how large did these earthquakes occur. The introduction of computerized catalogs brought a revolution in the way information about historical earthquakes was dealt with, because it necessitated the conversion of their objective aspects into parameters and codes, which could be handled in automatic form. The most advanced catalogs are the information systems in which data are presented in a critical way, and grouped according to research levels or within a pre-established logical hierarchy. Historical earthquake catalogs generally vary in quality from one country to another, but they are all based on descriptive data derived from human observation; from the long memory of the inhabited world. Historical seismology finds its basic data in three great record containers—namely, individuals (chronicles, letters, and diaries); institutions (archive sources); and scientific field.