气候变化领域集成服务门户(CCPortal): How Sediment Thickness Influences Subduction Dynamics and Seismicity

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DOI	10.1029/2019JB018964
	How Sediment Thickness Influences Subduction Dynamics and Seismicity
	Brizzi S.; van Zelst I.; Funiciello F.; Corbi F.; van Dinther Y.
发表日期	2020
ISSN	21699313
卷号	125 期号:8
英文摘要	It has long been recognized that sediments subducting along the megathrust influence the occurrence of giant (Mw ≥ 8.5) megathrust earthquakes. However, the limited observation span and the concurrent influence of multiple parameters on megathrust behavior prevent us from understanding how sediments affect earthquake size and frequency. Here, we address these limitations by using two-dimensional, visco-elasto-plastic, seismo-thermo-mechanical numerical models to isolate how sediment thickness affects subduction geometry and seismicity. Our results show that increasing sediment thickness on the incoming plate results in a decrease of the slab dip, as the trench retreats due to the seaward growth of the sedimentary wedge that also unbends the slab. This decrease in megathrust dip results in a wider seismogenic zone, so that the maximum magnitude of megathrust earthquakes increases. Concurrently, the recurrence time of characteristic events increases and partial ruptures are introduced. The maximum magnitude estimated for subduction segments with the thickest sediment input (Makran, West-Aegean, and Calabria) is distinctly higher than the instrumentally recorded magnitude. These segments may thus experience larger than as of yet observed earthquakes, albeit infrequently. Increasing sediment thickness also decreases megathrust normal stresses, as the seismogenic zone is more shallow and overlain by a lighter forearc structure. Thicker incoming plate sediments also favor more splay fault activity, whereas we observe more outer rise events for low sediment thickness. Finally, we demonstrate that modeling long-term subduction dynamics and sediment subduction is crucial for understanding and quantifying megathrust seismicity and seismic potential of subduction zones. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	megathrust maximum magnitude; natural data analysis; numerical modeling; sediments; seismicity; subduction zone processes
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187703
作者单位	Laboratory of Experimental Tectonics, University of Roma Tre, Rome, Italy; Natural and Experimental Tectonics Research Group, University of Parma, Parma, Italy; Now at Jackson School of Geosciences, University of Texas at Austin, Austin, TX, United States; Department of Earth Sciences, Seismology and Wave Physics, Institute of Geophysics, ETH Zürich, Zürich, Switzerland; Now at Institute of Geophysics and Tectonics, School of Earth and Environment, University of Leeds, Leeds, United Kingdom; Department of Earth Sciences, Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany; Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences, Potsdam, Germany; Department of Earth Sciences, Utrecht University, Utrecht, Netherlands
推荐引用方式 GB/T 7714	Brizzi S.,van Zelst I.,Funiciello F.,et al. How Sediment Thickness Influences Subduction Dynamics and Seismicity[J],2020,125(8).
APA	Brizzi S.,van Zelst I.,Funiciello F.,Corbi F.,&van Dinther Y..(2020).How Sediment Thickness Influences Subduction Dynamics and Seismicity.Journal of Geophysical Research: Solid Earth,125(8).
MLA	Brizzi S.,et al."How Sediment Thickness Influences Subduction Dynamics and Seismicity".Journal of Geophysical Research: Solid Earth 125.8(2020).