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Surface faulting earthquake clustering controlled by fault and shear-zone interactions
Author(s)
Language
English
Obiettivo Specifico
2T. Deformazione crostale attiva
Status
Published
JCR Journal
JCR Journal
Peer review journal
Yes
Title of the book
Issue/vol(year)
/13 (2022)
ISSN
2041-1723
Publisher
Nature PG
Pages (printed)
7126
Issued date
November 2022
Alternative Location
Subjects
Abstract
Surface faulting earthquakes are known to cluster in time from historical and palaeoseismic studies, but the mechanism(s) responsible for clustering, such as fault interaction, strain-storage, and evolving dynamic topography, are poorly quantified, and hence not well understood. We present a quantified replication of observed earthquake clustering in central Italy. Six active normal faults are studied using 36Cl cosmogenic dating, revealing out-of-phase periods of high or low surface slip-rate on neighboring structures that we interpret as earthquake clusters and anticlusters. Our calculations link stress transfer caused by slip averaged over clusters and anti-clusters on coupled fault/shear-zone structures to viscous flow laws. We show that (1) differential stress fluctuates during fault/shear-zone interactions, and (2) these fluctuations are of sufficient magnitude to produce changes in strain-rate on viscous shear zones that explain slip-rate changes on their overlying brittle faults. These results suggest that fault/shear-zone interactions are a plausible explanation for clustering, opening the path towards process-led seismic hazard assessments.
Type
article
File(s)
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Name
s41467-022-34821-5.pdf
Description
Open Access published article
Size
5.62 MB
Format
Adobe PDF
Checksum (MD5)
249b68cf7fde17e7dbe411e4f4137c17