Geological Criteria for Evaluating Seismicity

Abstract

This paper argues that the geologic record, and the late Quaternary history in particular, is a far more valuable tool in estimating seismicity and associated seismic hazard than has generally been appreciated. Those parts of the world with the longest historic records of earthquakes — some 2,000 yr for Japan and the Middle East and 3,000 yr for China — are the areas that should give us the greatest pause in using historic records for extrapolations, because earthquakes in these regions show surprisingly large long-term temporal and spatial variations. The very short historic record in North America should, therefore, be used with extreme caution in estimating possible future seismic activity. The geologic history of late Quaternary faulting is the most promising source of statistics on frequencies and locations of large shocks.

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