Subduction dynamics as revealed by trench migration
Subduction dynamics as revealed by trench migration
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DOI：
10.1029/2007tc002212
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发表时间：
2008-06
期刊：
影响因子：
4.2
通讯作者：
S. Lallemand;A. Heuret;C. Faccenna;F. Funiciello
中科院分区：
文献类型：
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作者：
S. Lallemand;A. Heuret;C. Faccenna;F. Funiciello
对沟槽迁移率的新估计使我们能够解决沟槽迁移和弧后应变的动态问题。我们表明，海沟迁移主要受俯冲板块速度 Vsub 控制，这很大程度上取决于其在海沟处的年龄。使用热和弱的弧到弧后区域作为应变传感器，我们定义了以不存在显着应变为特征的中性弧，这意味着力（板拉力、弯曲和锚定）沿着板之间的界面几乎平衡的地方。我们表明，中性俯冲带满足海沟和俯冲板块绝对运动之间的运动学关系：HS3 参考系中的 Vt = 0.5Vsub − 2.3（单位为 cm a−1）。当速度组合偏离运动平衡时就会发生变形。平衡作用在海沟上的力的扭矩分量表明，坚硬的（旧的）俯冲板块通过抵抗弯曲来促进海沟前进。
New estimates of trench migration rates allow us to address the dynamics of trench migration and back‐arc strain. We show that trench migration is primarily controlled by the subducting plate velocity Vsub, which largely depends on its age at the trench. Using the hot and weak arc to back‐arc region as a strain sensor, we define neutral arcs characterized by the absence of significant strain, meaning places where the forces (slab pull, bending, and anchoring) almost balance along the interface between the plates. We show that neutral subduction zones satisfy the kinematic relation between trench and subducting plate absolute motions: Vt = 0.5Vsub − 2.3 (in cm a−1) in the HS3 reference frame. Deformation occurs when the velocity combination deviates from kinematic equilibrium. Balancing the torque components of the forces acting at the trench indicates that stiff (old) subducting plates facilitate trench advance by resisting bending.