In Situ Stress and Pore Pressure in the Deep Interior of the Nankai Accretionary Prism, Integrated Ocean Drilling Program Site C0002
In Situ Stress and Pore Pressure in the Deep Interior of the Nankai Accretionary Prism, Integrated Ocean Drilling Program Site C0002
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南开增生棱柱内部深处的原位应力和孔隙压力，综合海洋钻探计划站点 C0002
DOI：
10.1002/2017gl075127
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发表时间：
2017
影响因子：
5.2
通讯作者：
Hirose Takehiro
中科院分区：
文献类型：
--
作者：
Kitajima Hiroko;Saffer Demian;Sone Hiroki;Tobin Harold;Hirose Takehiro
俯冲型巨型逆冲断层的强度和滑动行为不仅受断层带本身的物理性质和应力状态控制，而且受俯冲板块和俯冲板块围岩的物理性质和应力状态控制。在南海海槽，在综合大洋钻探计划C 0002现场钻了一个3公里深的立管钻孔，进入熊野弧前盆地和下面的增生棱柱体。我们通过整合钻井数据、地球物理测井和井下测量，使用描述沉积物压实行为作为加载路径函数的经验关系，量化了C 0002现场的完整原地应力张量和孔隙压力。熊野盆地在单轴垂直应变条件下加载，而下面的棱柱体加载了更大的差应力，具有适度升高的孔隙压力，位于走滑断层区如果水平应力随时间或深度变化，和/或如果沿大逆冲断层的剪切应力沿着较低，则这可以与大逆冲断层上的滑动相一致。
Strength and slip behaviors of subduction megathrusts are controlled by the physical properties and stress state not only of the fault zones themselves but also the adjacent wall rocks in overriding and subducting plates. In the Nankai Trough, a 3 km deep riser borehole at Integrated Ocean Drilling Program Site C0002 was drilled into the Kumano fore‐arc basin and the underlying accretionary prism. We quantify the full in situ stress tensor and pore pressure at Site C0002 by integrating drilling data, geophysical logging, and downhole measurements using empirical relations that describe sediment compaction behavior as a function of loading path. The Kumano Basin is loaded in uniaxial vertical strain conditions, whereas the prism below is loaded with greater differential stress, has a modestly elevated pore pressure, and lies in a strike‐slip faulting regime. This can be reconciled with slip on the megathrust fault if the horizontal stresses vary with time or depth and/or if shear stress along the megathrust is low.