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Scaling and Variability of Interacting Repeating Earthquake Sequences Controlled by Asperity Density
Author(s) -
Dublanchet P.
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl084614
Subject(s) - asperity (geotechnical engineering) , geology , scaling , seismology , induced seismicity , seismic moment , fault (geology) , moment (physics) , san andreas fault , creep , geometry , physics , geotechnical engineering , mathematics , classical mechanics , thermodynamics
The period T r of repeating earthquakes scales asV c − 1M 0 1 / 6 ,V c being the creep rate of the fault and M 0 the seismic moment of the events. Models consisting of a single asperity embedded in a creeping fault capture this scaling but fail to explain the variability in recurrence time observed during natural sequences. Here I show by a statistical analysis of repeating earthquakes generated in a rate‐and‐state fault model, that the observed scaling and variability in T r are reproduced if a population of asperities is considered. For that, the density of asperities needs to be smaller than a critical threshold allowing system‐size ruptures. Creep mediated stress transfers control the variability in T r in this regime, which increases with asperity density. Beyond that density, the seismicity is highly clustered leading to moment‐independent recurrence. The dynamics of repeating earthquakes could therefore be an indicator of the amount of seismogenic asperities on creeping faults.