Distributed normal faulting in the tip zone of the South Alkyonides Fault System, Gulf of Corinth, constrained using 36Cl exposure dating of Late-Quaternary wave-cut platforms.

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Authors

Jenni Robertson, Gerald Roberts, Francesco Iezzi, Marco Meschis, Delia Gheorghiu, Diana Sahy, Chris Bristow, Claudia Sgambato

Abstract

In order to investigate the geometry, rates and kinematics of active faulting in the region close to the tip of a major crustal-scale normal fault in the Gulf of Corinth, Greece, we have mapped faults and dated their offsets using a combination of 234U/230Th coral dates and in situ 36Cl cosmogenic exposure ages for sediments and wave-cut platforms deformed by the faults. Our results show that deformation in the tip zone is distributed across as many as eight faults arranged within ~700 m across strike, each of which deforms deposits and landforms associated with the 125 ka marine terrace of Marine Isotope Stage 5e. Summed throw-rates across strike achieve values as high as 0.3-1.6 mm/yr, values that are relatively high compared to that at the centre of the crustal-scale fault (2-3 mm/yr from Holocene palaeoseismology and 3-4 mm/yr from GPS geodesy). The relatively high deformation rate and distributed deformation rate in the tip zone are discussed in terms of stress enhancement from rupture of neighbouring crustal-scale faults and in terms of how this should be considered during fault-based seismic hazard assessment.

DOI

https://doi.org/10.31223/osf.io/r4jpa

Subjects

Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure

Keywords

normal faulting, 36Cl exposure dating, Deformed marine terraces, Distributed faulting, Fault tip zone, Wave-cut platform

Dates

Published: 2019-10-24 11:01

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License

GNU Lesser General Public License (LGPL) 2.1

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