Thermal regime and slab dehydration beneath the Izu‐Bonin arc: Implications for fast and slow subduction earthquakes
Thermal regime and slab dehydration beneath the Izu‐Bonin arc: Implications for fast and slow subduction earthquakes
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DOI：
10.1111/ter.12568
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发表时间：
2021-11
期刊：
影响因子：
2.4
通讯作者：
Weiling Zhu;Yingfeng Ji;Rui Qu;Chaodi Xie;S. Yoshioka;D. Zeng
中科院分区：
文献类型：
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作者：
Weiling Zhu;Yingfeng Ji;Rui Qu;Chaodi Xie;S. Yoshioka;D. Zeng
从冷弧到热弧的过渡被认为是俯冲动力学的基础。然而，沿打击方向发生显著变化的冷鼻的范围和深度是难以约束的。通过结合三维高分辨率板块地形和MORVEL板块运动场来约束热力学模型，我们估计了伊豆-博宁地区的俯冲热状态和岩石脱水。多层热液体系逐渐由冷前弧向不冷前弧过渡，并伴随着沿走向变化的大规模俯冲脱水过程。榴辉石化和哈兹布尔石化引起的脱水脆化作用影响了特大逆冲构造上快慢地震的发生。令人印象深刻的是，冷鼻被限制在弧和莫霍深度板块界面之间的60公里深度。深层俯冲板块冷中心温度的降低和岩石哈尔兹布尔化的延迟，是热弧后界面下深地震发生的原因。
The transition from cold forearc to hot arc is considered fundamental to subduction dynamics. However, the range and depth of the cold nose changing significantly along the strike are difficult to constrain. By incorporating the three‐dimensional high‐resolution slab topography and MORVEL plate motion field to constrain thermomechanical modelling, we estimate the subduction thermal state and petrological dehydration in Izu‐Bonin. The multilayered hydrothermal regime gradually transitions from cold to less cold forearc, associated with a large‐scale subduction dewatering process varying along the strike. The dehydration embrittlement resulting from eclogitization and harzburgitization influences the occurrence of fast to slow earthquakes on megathrusts. Impressively, the cold nose is constrained to a depth of 60 km between the arc and Moho‐depth plate interface. The lowered temperature and delay of rock harzburgitization in the cold center of the subducted plate at depth contribute to the occurrence of deep earthquakes below the hot backarc interface.