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Surface faulting earthquake clustering controlled by fault and shear-zone interactions

Mildon, Zoë K.; Roberts, Gerald P.; Faure Walker, Joanna P.; Beck, Joakim; Papanikolaou, Ioannis; Michetti, Alessandro M.; Toda, Shinji; Iezzi, Francesco; Campbell, Lucy; McCaffrey, Kenneth J.W.; Shanks, Richard; Sgambato, Claudia; Robertson, Jennifer; Meschis, Marco; Vittori, Eutizio

Surface faulting earthquake clustering controlled by fault and shear-zone interactions Thumbnail


Authors

Zoë K. Mildon

Gerald P. Roberts

Joanna P. Faure Walker

Joakim Beck

Ioannis Papanikolaou

Alessandro M. Michetti

Shinji Toda

Francesco Iezzi

Lucy Campbell

Richard Shanks

Claudia Sgambato

Jennifer Robertson

Marco Meschis

Eutizio Vittori



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.

Citation

Mildon, Z. K., Roberts, G. P., Faure Walker, J. P., Beck, J., Papanikolaou, I., Michetti, A. M., …Vittori, E. (2022). Surface faulting earthquake clustering controlled by fault and shear-zone interactions. Nature Communications, 13(1), Article 7126. https://doi.org/10.1038/s41467-022-34821-5

Journal Article Type Article
Acceptance Date Nov 3, 2022
Online Publication Date Nov 21, 2022
Publication Date 2022
Deposit Date Dec 2, 2022
Publicly Available Date Dec 2, 2022
Journal Nature Communications
Publisher Nature Research
Peer Reviewed Peer Reviewed
Volume 13
Issue 1
Article Number 7126
DOI https://doi.org/10.1038/s41467-022-34821-5

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http://creativecommons.org/licenses/by/4.0/

Copyright Statement
This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.




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