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Variability of displacement at a point: Implications for earthquake‐size distribution and rupture hazard on faults

Bulletin of the Seismological Society of America

By:
, , and
DOI: 10.1785/​0120120159

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Abstract

To investigate the nature of earthquake‐magnitude distributions on faults, we compare the interevent variability of surface displacement at a point on a fault from a composite global data set of paleoseismic observations with the variability expected from two prevailing magnitude–frequency distributions: the truncated‐exponential model and the characteristic‐earthquake model. We use forward modeling to predict the coefficient of variation (CV) for the alternative earthquake distributions, incorporating factors that would effect observations of displacement at a site. The characteristic‐earthquake model (with a characteristic‐magnitude range of ±0.25) produces CV values consistent with the data (CV∼0.5) only if the variability for a given earthquake magnitude is small. This condition implies that rupture patterns on a fault are stable, in keeping with the concept behind the model. This constraint also bears upon fault‐rupture hazard analysis, which, for lack of point‐specific information, has used global scaling relations to infer variability in average displacement for a given‐size earthquake. Exponential distributions of earthquakes (from M 5 to the maximum magnitude) give rise to CV values that are significantly larger than the empirical constraint. A version of the model truncated at M 7, however, yields values consistent with a larger CV (∼0.6) determined for small‐displacement sites. Although this result allows for a difference in the magnitude distribution of smaller surface‐rupturing earthquakes, it may reflect, in part, less stability in the displacement profile of smaller ruptures and/or the tails of larger ruptures.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Variability of displacement at a point: Implications for earthquake‐size distribution and rupture hazard on faults
Series title:
Bulletin of the Seismological Society of America
DOI:
10.1785/​0120120159
Volume
103
Issue:
2A
Year Published:
2013
Language:
English
Publisher:
GeoScienceWorld
Contributing office(s):
Earthquake Science Center
Description:
24 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Bulletin of the Seismological Society of America
First page:
651
Last page:
674
Country:
United States