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Fault Geometry and Slip Distribution at Depth of the 1997 Mw 7.2 Zirkuh Earthquake: Contribution of Near-Field Displacement Data

Authors :
Mathilde Marchandon
Olivier Cavalié
Mathilde Vergnolle
Henriette Sudhaus
Géoazur (GEOAZUR 7329)
Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur
Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])
Christian-Albrechts-Universität zu Kiel (CAU)
COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])
Source :
Journal of Geophysical Research : Solid Earth, Journal of Geophysical Research : Solid Earth, American Geophysical Union, 2018, 123 (2), pp.1904-1924. ⟨10.1002/2017JB014703⟩, Journal of Geophysical Research : Solid Earth, 2018, 123 (2), pp.1904-1924. ⟨10.1002/2017JB014703⟩
Publication Year :
2018
Publisher :
HAL CCSD, 2018.

Abstract

International audience; In this study, we reestimate the source model of the 1997 Mw 7.2 Zirkuh earthquake (northeastern Iran) by jointly optimizing intermediate‐field Interferometry Synthetic Aperture Radar data and near‐field optical correlation data using a two‐step fault modeling procedure. First, we estimate the geometry of the multisegmented Abiz fault using a genetic algorithm. Then, we discretize the fault segments into subfaults and invert the data to image the slip distribution on the fault. Our joint‐data model, although similar to the Interferometry Synthetic Aperture Radar‐based model to the first order, highlights differences in the fault dip and slip distribution. Our preferred model is ∼80° west dipping in the northern part of the fault, ∼75° east dipping in the southern part and shows three disconnected high slip zones separated by low slip zones. The low slip zones are located where the Abiz fault shows geometric complexities and where the aftershocks are located. We interpret this rough slip distribution as three asperities separated by geometrical barriers that impede the rupture propagation. Finally, no shallow slip deficit is found for the overall rupture except on the central segment where it could be due to off‐fault deformation in quaternary deposits.

Details

Language :
English
ISSN :
21699313 and 21699356
Database :
OpenAIRE
Journal :
Journal of Geophysical Research : Solid Earth, Journal of Geophysical Research : Solid Earth, American Geophysical Union, 2018, 123 (2), pp.1904-1924. ⟨10.1002/2017JB014703⟩, Journal of Geophysical Research : Solid Earth, 2018, 123 (2), pp.1904-1924. ⟨10.1002/2017JB014703⟩
Accession number :
edsair.doi.dedup.....04c63d3f66a32a270aff584936462621
Full Text :
https://doi.org/10.1002/2017JB014703⟩