Moreno E J, Manea V C, Manea M, Yoshioka S, Suenaga N, Bayona A
Research Center for Urban Safety and Security, Kobe University, Kobe, 657-8501, Japan.
Computational Geodynamics Laboratory, Centro de Geociencias, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro, 76230, México.
Sci Rep. 2023 Oct 25;13(1):18313. doi: 10.1038/s41598-023-45370-2.
The subduction of the Philippine Sea (PHS) plate along the Nankai Trough in in southwest Japan is a relatively recent process compared with subduction along the Japan Trench in northeast Japan. However, the tectonic evolution of the PHS plate along the Nankai Trough is still controversial and not fully understood. There are several competing hypotheses based on different estimates for the time variations of convergence rate and plate age. Our study employs numerical modelling of subduction in order to evaluate the slab evolution for the last 15 Myr and aims to evaluate each tectonic scenario against the present-day slab geometry along a profile passing through the Shikoku and Chugoku regions. The modelling strategy involves a parameter study where subduction initiation and various subduction parameters are analyzed in terms of subduction geometry evolution. Two-dimensional visco-elasto-plastic numerical simulations of spontaneous bending subduction predict that convergence rate and plate age variations play an important role in the evolution of subduction geometry. Modeling results after 15 Myr of evolution reveal that the tectonic model based on a high convergence rate between ~ 15 Ma and ~ 3 Ma produces a slab geometry that agrees well with the observed present-day slab shape specific for the Shikoku and Chugoku regions.
与日本东北部日本海沟的俯冲相比，菲律宾海板块沿日本西南部南海海槽的俯冲是一个相对较新的过程。然而，菲律宾海板块沿南海海槽的构造演化仍存在争议，尚未完全被理解。基于对汇聚速率和板块年龄时间变化的不同估计，存在几种相互竞争的假说。我们的研究采用俯冲数值模拟来评估过去1500万年的板块演化，并旨在根据沿四国和中国地区的剖面，对照现今板块几何形状评估每种构造情形。建模策略涉及一项参数研究，其中从俯冲几何形状演化的角度分析俯冲起始和各种俯冲参数。自发弯曲俯冲的二维粘弹塑性数值模拟预测，汇聚速率和板块年龄变化在俯冲几何形状演化中起重要作用。演化1500万年后的建模结果表明，基于约1500万年前至约300万年前高汇聚速率的构造模型产生的板块几何形状与四国和中国地区现今观测到的特定板块形状吻合良好。
