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Published March 2019 | Published + Supplemental Material
Journal Article Open

Source parameters of the 2017 M_w 6.2 Yukon earthquake doublet inferred from coseismic GPS and ALOS-2 deformation measurements

Abstract

We investigated an M_w ∼ 6.2 earthquake doublet on the border of the USA and Canada using ALOS2 Light-of-Sight displacements and GPS measurements. We selected three L-band ALOS-2 interfergorams with temporal baselines of one yr to extract coseismic deformation maps, in which master and slave images were both acquired in July. A subpixel-based alignment and another range spectral splitting techniques under the GAMMA InSAR software framework were applied to improve the interferometric coherence and reduce the effects of phase anomalies in two of the three interferometric pairs due to either ionospheric delay or a potential focusing issues in the generation of the ALOS2 SLC data. The updated interferograms convincingly reveal deformation fringe patterns produced by the two earthquakes. We conducted a nonlinear geophysical inversion to estimate the geometric parameters of the earthquakes with the InSAR and GPS measurements. The best-fitting model shows that a thrust faulting on a reverse fault and left-lateral strike-slip faulting on a nearly vertical fault with the centroid depths of 9.3±0.6 and 8.4±0.7 km, respectively, are most likely responsible for the earthquake doublet. The eastern Denali fault (EDF) and Duke River fault are major active faults in the region and the earthquake doublet could be due to reactivation of the part of the two faults system.

Additional Information

© 2018 The Author(s). Published by Oxford University Press on behalf of The Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model). Accepted 2018 November 21. Received 2018 November 11; in original form 2018 March 01. Published: 22 November 2018. We sincerely thank the Editor and two reviewers' thorough reviews which significantly improved the manuscript. We thank JAXA for providing ALOS2 ScanSAR and StripMap SAR data through a RA6 PI project (3159). We also thank Mrs Rosie Cobbett from the Yukon geological survey for providing local geological information. Dr Xiaohui He is thanked for providing the GPS data and sharing their newly published results on the two events. We also thank the funding from Guangdong Province Introduced Innovative R&D Team of Geological Processes and Natural Disasters around the South China Sea (2016ZT06N331). All figures are prepared with the Genetic Mapping Tool (GMT) (Wessel & Smith 1998; Wessel et al. 2013). We thank Dr Urs Wegmuller and Dr Charles L. Werner for the insightful comments on the use of the GAMMA software package. The work related with GACOS was partly supported by the UK NERC through the Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics (COMET, ref.: come30001) and the LICS project (ref. NE/K010794/1).

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Created:
August 19, 2023
Modified:
October 20, 2023