Academic Journal

How Sediment Thickness Influences Subduction Dynamics and Seismicity

التفاصيل البيبلوغرافية
العنوان: How Sediment Thickness Influences Subduction Dynamics and Seismicity
المؤلفون: Brizzi, S., van Zelst, I., Funiciello, F., Corbi, F., van Dinther, Y.
المساهمون: Tectonics
سنة النشر: 2020
مصطلحات موضوعية: Taverne
الوصف: 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.
نوع الوثيقة: article in journal/newspaper
وصف الملف: application/pdf
اللغة: English
تدمد: 2169-9313
Relation: https://dspace.library.uu.nl/handle/1874/408971
الاتاحة: https://dspace.library.uu.nl/handle/1874/408971
Rights: info:eu-repo/semantics/OpenAccess
رقم الانضمام: edsbas.CB6AD953
قاعدة البيانات: BASE