Iezzi, F., Roberts, G., Faure Walker, J., Papanikolaou, I., Ganas, A., Deligiannakis, G., Beck, J., Wolfers, S. and Gheorghiu, D. (2021) Temporal and spatial earthquake clustering revealed through comparison of millennial strain-rates from 36Cl cosmogenic exposure dating and decadal GPS strain-rate. Scientific Reports, 11, 23320. (doi: 10.1038/s41598-021-02131-3) (PMID:34857777) (PMCID:PMC8639784)
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Abstract
To assess whether continental extension and seismic hazard are spatially-localized on single faults or spread over wide regions containing multiple active faults, we investigated temporal and spatial slip-rate variability over many millennia using in-situ 36Cl cosmogenic exposure dating for active normal faults near Athens, Greece. We study a ~ NNE-SSW transect, sub-parallel to the extensional strain direction, constrained by two permanent GPS stations located at each end of the transect and arranged normal to the fault strikes. We sampled 3 of the 7 seven normal faults that exist between the GPS sites for 36Cl analyses. Results from Bayesian inference of the measured 36Cl data implies that some faults slip relatively-rapidly for a few millennia accompanied by relative quiescence on faults across strike, defining out-of-phase fault activity. Assuming that the decadal strain-rate derived from GPS applies over many millennia, slip on a single fault can accommodate ~ 30–75% of the regional strain-rate for a few millennia. Our results imply that only a fraction of the total number of Holocene active faults slip over timescales of a few millennia, so continental deformation and seismic hazard are localized on specific faults and over a length-scale shorter than the spacing of the present GPS network over this time-scale. Thus, (1) the identification of clustered fault activity is vital for probabilistic seismic hazard assessments, and (2) a combination of dense geodetic observations and palaeoseismology is needed to identify the precise location and width of actively deforming zones over specific time periods.
Item Type: | Articles |
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Additional Information: | This work has been funded by NERC Grant CIAF 9183-1017, NERC Studentship NE/L002485/1, MIS 5002697/ NSRF 2014-2020, Greece, and the European Union (European Regional Development Fund). A.G acknowledges funding by the project “HELPOS—Hellenic System for Lithosphere Monitoring”. |
Status: | Published |
Refereed: | Yes |
Glasgow Author(s) Enlighten ID: | Gheorghiu, Dr Delia M |
Authors: | Iezzi, F., Roberts, G., Faure Walker, J., Papanikolaou, I., Ganas, A., Deligiannakis, G., Beck, J., Wolfers, S., and Gheorghiu, D. |
College/School: | College of Science and Engineering > Scottish Universities Environmental Research Centre |
Journal Name: | Scientific Reports |
Publisher: | Nature Research |
ISSN: | 2045-2322 |
ISSN (Online): | 2045-2322 |
Copyright Holders: | Copyright © 2021 The Authors |
First Published: | First published in Scientific Reports 11: 23320 |
Publisher Policy: | Reproduced under a Creative Commons License |
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