Constant strain accumulation rate between major earthquakes on the North Anatolian Fault
Abstract
Earthquakes are caused by the release of tectonic strain accumulated between events. Recent advances in satellite geodesy mean we can now measure this interseismic strain accumulation with a high degree of accuracy. But it remains unclear how to interpret short-term geodetic observations, measured over decades, when estimating the seismic hazard of faults accumulating strain over centuries. Here, we show that strain accumulation rates calculated from geodetic measurements around a major transform fault are constant for its entire 250-year interseismic period, except in the ~10 years following an earthquake. The shear strain rate history requires a weak fault zone embedded within a strong lower crust with viscosity greater than ~10^(20) Pa s. The results support the notion that short-term geodetic observations can directly contribute to long-term seismic hazard assessment and suggest that lower-crustal viscosities derived from postseismic studies are not representative of the lower crust at all spatial and temporal scales.
Additional Information
© 2018 The Author(s). This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. Received: 25 August 2017; Accepted: 09 March 2018; Published online: 11 April 2018. This work has been supported by the UK Natural Environment Research Council (NERC) project grant number: NE/I028017/1, which supported the lead author's Ph.D. studentship as part of the FaultLab project at the University of Leeds. The Envisat satellite data are freely available and were obtained from the European Space Agency's Geohazard Supersites project. The GNSS data were obtained from the Global Strain Rate Model project website (http://gsrm.unavco.org). Many of the figures in this paper were made using the public domain Generic Mapping Tools (GMT) software. Part of this work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. COMET is the NERC Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics. Contributions: E.H. and T.J.W. designed and wrote the paper. E.H., R.J.W., and R.L. processed the InSAR data, and D.P.S.B. and R.J.W. corrected the data for atmospheric errors. A.H. implemented the iterative unwrapping procedure into StaMPS. E.H. performed the modelling and strain rate analysis. All authors contributed to finalising and editing the paper. Competing interests: The authors declare no competing interests.Attached Files
Published - s41467-018-03739-2.pdf
Supplemental Material - 41467_2018_3739_MOESM1_ESM.pdf
Supplemental Material - 41467_2018_3739_MOESM2_ESM.pdf
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Additional details
- PMCID
- PMC5895838
- Eprint ID
- 85888
- Resolver ID
- CaltechAUTHORS:20180417-081113555
- Natural Environment Research Council (NERC)
- NE/I028017/1
- NASA/JPL/Caltech
- Created
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2018-04-17Created from EPrint's datestamp field
- Updated
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2022-03-11Created from EPrint's last_modified field