ORCID
- Zoë K. Mildon: 0000-0001-6192-765X
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.
Publication Date
2022-11-21
Publication Title
Nature Communications
Volume
13
Issue
1
ISSN
2041-1723
Embargo Period
2022-12-09
Recommended Citation
Mildon, Z., Roberts, G., Faure, W., Beck, J., Papanikolaou, I., Michetti, A., Toda, S., Iezzi, F., Campbell, L., McCaffrey, K., Shanks, R., Sgambato, C., Robertson, J., Meschis, M., & Vittori, E. (2022) 'Surface faulting earthquake clustering controlled by fault and shear-zone interactions', Nature Communications, 13(1). Available at: 10.1038/s41467-022-34821-5
