Tectono-seismic characteristics of faults in the shallow portion of an accretionary prism
Tectono-seismic characteristics of faults in the shallow portion of an accretionary prism
复制标题
增生棱柱浅部断层的构造地震特征
DOI：
10.1016/j.tecto.2018.01.014
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发表时间：
2018
期刊：
影响因子：
2.9
通讯作者：
T.
中科院分区：
文献类型：
--
作者：
Hirono;T. and Ishikawa;T.
为了了解俯冲-增生系统浅部断层的构造-地震演化，我们通过进行多种构造、地球化学和矿物学分析，研究了日本房总半岛惠美群（霍塔群）化石增生棱柱体中的主要断层。由于地层相对较浅（埋深1-4 km），与俯冲、增生和隆升过程有关的早期变形在三个主要断裂带中保存完好。综合前人的研究成果和我们的地球化学、矿物学研究结果，我们认为早期的高孔隙流体压力下的近海沟背景下的断裂活动和第二阶段的相对较深的沿着俯冲方向的断裂活动，表现为速度强化特征，对应于地壳的运动变形;在晚期断裂活动中，可能与增生和隆升过程有关，地球化学温度代用指标揭示了高温流体，通过热增压机制触发断层弱化，并可能导致海啸的产生。
To understand the tectono-seismic evolution of faults in the shallow part of a subduction–accretion system, we examined major faults in a fossil accretionary prism, the Emi Group (Hota Group), Boso Peninsula, Japan, by performing multiple structural, geochemical, and mineralogical analyses. Because the strata are relatively shallow (burial depth, 1–4 km), early stage deformation related to subduction, accretion, and uplifting processes is well preserved in three dominant fault zones. On the basis of both previous findings and our geochemical and mineralogical results, we inferred that early stage faulting in a near-trench setting under high pore fluid pressure and second stage faulting at relatively deep along subduction corresponded to aseismic deformations, as shown by velocity strengthening characteristics; and during late stage faulting, probably in association with accretion and uplift processes, a high-temperature fluid, revealed by a geochemical temperature proxy, triggered fault weakening by a thermal pressurization mechanism, and potentially led to the generation of a tsunami.