Slip distribution of the 2015 Lefkada earthquake and its implications for fault segmentation

Bie, Lidong, González, Pablo J. and Rietbrock, Andreas (2017) Slip distribution of the 2015 Lefkada earthquake and its implications for fault segmentation. Geophysical Journal International, 210 (1). pp. 420-427. ISSN 0956-540X

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Abstract

It is widely accepted that fault segmentation limits earthquake rupture propagations and therefore earthquake size. While along-strike segmentation of continental strike-slip faults is well observed, direct evidence for segmentation of off-shore strike-slip faults is rare. A comparison of rupture behaviours in multiple earthquakes might help reveal the characteristics of fault segmentation. In this work, we study the 2015 Lefkada earthquake, which ruptured a major active strike slip fault offshore Lefkada Island, Greece. We report ground deformation mainly on the Lefkada Island measured by interferometric synthetic radar (InSAR), and infer a coseismic distributed slip model. To investigate how the fault location affects the inferred displacement based on our InSAR observations, we conduct a suite of inversions by taking various fault location from different studies as a prior. The result of these test inversions suggests that the Lefkada fault trace is located just offshore Lefkada Island. Our preferred model shows that the 2015 earthquake main slip patches are confined to shallow depth (<10 km), with amaximum slip of~1.6 m. In comparison to the 2003 earthquake,which mainly ruptured the northern part of the Lefkada fault, we suggest that the 2015 earthquake closed the seismic gap, at least partially, left by the 2003 earthquake by rupturing the shallow part of the Lefkada fault. The spatial variation in slip distributions for the two earthquakes reveals segmentation along strike, and possibly downdip of the Lefkada fault. A comparison of aftershock locations and coseismic slip distribution shows that most aftershocks appear near the edge of main coseismic slip patches.

Item Type: Article
Additional Information: Funding Information: We thank the editor (Prof Duncan Agnew) and two anonymous reviewers for their helpful comments. This work was partially supported by the UK Natural Environmental Research Council (NERC) through NE/K011006/1, NE/P008828/1, and the Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics (COMET, GA/13/M/031, http://comet.nerc.ac.uk). The Sentinel-1 interferograms presented are a derived work of Copernicus data, subject to the ESA use and distribution conditions. We thank Dr Stephen Hicks for constructive comments on an early version of this paper. Publisher Copyright: © The Authors 2017.
Uncontrolled Keywords: earthquake source observations,europe,radar interferometry,geophysics,geochemistry and petrology ,/dk/atira/pure/subjectarea/asjc/1900/1908
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Depositing User: LivePure Connector
Date Deposited: 25 Apr 2022 09:31
Last Modified: 25 Apr 2022 09:31
URI: https://ueaeprints.uea.ac.uk/id/eprint/84774
DOI: 10.1093/gji/ggx171

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