Strike slip motion and the triggering of subduction initiation
- Creators
- Li, Yida
- Gurnis, Michael
Abstract
Plate tectonic reconstructions of three of the best-defined Cenozoic subduction initiation (SI) events in the western Pacific, Izu-Bonin-Mariana, Vanuatu, and Puysegur subduction zones, show substantial components of strike-slip motion before and during the subduction initiation. Using computational models, we show that strike-slip motion has a large influence on the effective strength of incipient margins and the ease of subduction initiation. The parameter space associated with visco-elasto-plastic rheologies, plate weakening, and plate forces and kinematics is explored and we show that subduction initiates more easily with a higher force, a faster weakening, or greater strike-slip motion. With the analytical solution, we demonstrate that the effect of strike-slip motion can be equivalently represented by a modified weakening rate. Along transpressive margins, we show that a block of oceanic crust can become trapped between a new thrust fault and the antecedent strike-slip fault and is consistent with structural reconstructions and gravity models of the Puysegur margin. Together, models and observations suggest that subduction initiation can be triggered when margins become progressively weakened to the point that the resisting forces become smaller than the driving forces, and as the negative buoyancy builds up, the intraplate stress eventually turns from compressional into extensional. The analytical formulation of the initiation time, t_(SI), marking the moment when intraplate stress flips sign, is validated with a computational models. The analytical solution shows that t_(SI) is dominated by convergence velocity, while the plate age, strike-slip velocity, and weakening rate all have a smaller but still important effect on the time scale of subduction initiation.
Additional Information
© 2023 Li and Gurnis. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. This article is part of the Research Topic Tectono-Magmatism, Metallogenesis, and Sedimentation at Convergent Margins. Supported by the National Science Foundation through awards OCE–1654766, EAR–1645775, and OCE–2049086. This work used Stampede-2 at the Texas Advanced Computer Center from the Extreme Science and Engineering Discovery Environment (XSEDE), which was supported by National Science Foundation. Author contributions. YL contributes to study conception, model setup, manuscript preparation, interpretation MG contributes to study conception, manuscript preparation, interpretation. All authors reviewed the results and approved the final version of the manuscript. Data availability statement. The datasets presented in this study can be found in online repositories. The names of the repository/repositories and accession number(s) can be found in the article/Supplementary Material. The datasets for this study can be found in the CaltechDATA at https://doi.org/110.22002/ae55y-m7q16. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.Attached Files
Published - feart-11-1156034.pdf
Supplemental Material - Data_Sheet_1.pdf
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Additional details
- Eprint ID
- 121673
- Resolver ID
- CaltechAUTHORS:20230602-251509000.4
- OCE-1654766
- NSF
- EAR-1645775
- NSF
- OCE-2049086
- NSF
- Created
-
2023-06-12Created from EPrint's datestamp field
- Updated
-
2023-10-20Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences, Seismological Laboratory