Publication Date:
2019
Description:
Abstract
While power‐law distributions in seismic moment and inter‐event times are ubiquitous in regional earthquake catalogs, the statistics of individual faults remains controversial. Continuum fault models without heterogeneity typically produce characteristic earthquakes or a narrow range of sizes, leading to the view that regional statistics originate from interaction of multiple faults. I present theoretical arguments and numerical simulations demonstrating that seismicity on homogeneous planar faults can span several orders of magnitude in rupture dimensions and inter‐event times, if the fault dimension W is sufficiently large compared to a characteristic length Lcrit, related to the nucleation dimension. Large faults are increasingly less characteristic, with the fraction of system‐size ruptures proportional to (Lcrit/W)1/2. Earthquake statistics for large W/Lcrit is remarkably close to nature, exhibiting Omori decay and power‐law distributed rupture lengths. Simple crack models are consistent with a Gutenberg‐Richter distribution with b=3/4, and provide a physical basis for these distributions on individual faults.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
