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Unpublished Paper
USGS NEHRP Grant 1434-HQ-96-GR-02752, Final Technical Report (1998)
  • James P. McCalpin
Compiled data from numerous neotectonic-geomorphic and trench studies reveals patterns in the spatial and temporal variation of coseismic fault displacement. Recurrence intervals between successive large earthquakes on faults define a near-symmetrical probability distribution with a coefficient of variance of 0.36. Normal faults have the most regular recurrence, and subduction zones the most variable. Variability in recurrence times at a site is not dependent on the number of recurrence intervals dated at that site. During historic surface-rupturing earthquakes slip has varied widely along strike. Based on 56 ruptures where more than 15 displacement measurements were made, the generic pattern is for average displacement (Davg) to equal 0.35 of maximum displacement (Dmax). The frequency of smaller-than-average displacements is much greater than larger-than-average ones, with less than 5% of displacements being larger than 90% of the maximum. The frequency distributions permit one to estimate Dmax or Davg from one or more random measurements of displacement, which then permits an estimate of paleoearthquake magnitude.
  • paleoseismology,
  • surface rupture,
  • recurrence interval
Publication Date
Citation Information
James P. McCalpin. "STATISTICS OF PALEOSEISMIC DATA" USGS NEHRP Grant 1434-HQ-96-GR-02752, Final Technical Report (1998)
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