Temporal and spatial earthquake clustering revealed through comparison of millennial strain-rates from 36 Cl cosmogenic exposure dating and decadal GPS strain-rate.

Autor: Iezzi F; DiSPUTer, Università Degli Studi 'Gabriele d'Annunzio' Chieti-Pescara, Via dei Vestini, 66100, Chieti, Italy. francesco.iezzi.15@ucl.ac.uk.; Department of Earth and Planetary Sciences, Birkbeck, University of London, Malet Street, London, WC1E 7HX, UK. francesco.iezzi.15@ucl.ac.uk., Roberts G; Department of Earth and Planetary Sciences, Birkbeck, University of London, Malet Street, London, WC1E 7HX, UK., Faure Walker J; Institute for Risk and Disaster Reduction, University College London, Gower Street, London, WC1E 6BT, UK., Papanikolaou I; Mineralogy-Geology Laboratory, Department of Natural Resources Development and Agricultural Engineering, Agricultural University of Athens, 75 Iera Odos, 118-55, Athens, Greece., Ganas A; Institute of Geodynamics, National Observatory of Athens, Lofos Nymfon, 11810, Athens, Greece., Deligiannakis G; Mineralogy-Geology Laboratory, Department of Natural Resources Development and Agricultural Engineering, Agricultural University of Athens, 75 Iera Odos, 118-55, Athens, Greece., Beck J; Computer, Electrical and Mathematical Sciences & Engineering (CEMSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia., Wolfers S; Computer, Electrical and Mathematical Sciences & Engineering (CEMSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia., Gheorghiu D; Scottish Universities Environmental Research Centre, Rankine Avenue, East Kilbride, G750QF, UK.
Jazyk: angličtina
Zdroj: Scientific reports [Sci Rep] 2021 Dec 02; Vol. 11 (1), pp. 23320. Date of Electronic Publication: 2021 Dec 02.
DOI: 10.1038/s41598-021-02131-3
Abstrakt: 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 36 Cl 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 36 Cl analyses. Results from Bayesian inference of the measured 36 Cl 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.
(© 2021. The Author(s).)
Databáze: MEDLINE
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