GOUGE - Hydrothermal deformation experiments on ICDP fault zone materials

地震孕育区钻探得到的断层泥可能有助于揭示地震机制，从而间接有助于评估社会风险。ICDP在挤压(车龙铺，台湾)、走滑(美国圣安德烈亚斯)和伸展系统(科林斯湾，希腊)中发现了这些物质。在这项建议中，我们建议开发一种加热(高达200-250°C)、背压直接剪切仪，其中这种断层泥可以在高达200兆帕的法向应力下进行测试。它将提供广泛的机会来精确测量沉积物和岩石的与速率相关的摩擦强度，加载、破坏和剪切运动过程中的孔压和渗透率的瞬变，以及已知或推断的原地条件下的扩容和剪切强化压实和加强。主要焦点将是SAFOD项目，因为目前正在回收新的核心。它还将补充来自Nobeaka和Nojima断层的材料、来自Shimanto带或Franciscan杂岩(覆盖高达约350摄氏度的宽温谱)的岩石，以及从克里特岛(也是ICDP潜在钻探地点)板片断裂中挖掘出的岩石。从中期角度来看，这些结果可以与重要的海洋相当物相比较，例如南开海槽的主要滑脱泥(将在与DV Chikyu的IODP内恢复)和其他地方，从而将大陆和海洋领域的两个科学钻探计划联系起来。

Fault gouge from seismogenic zone drilling may shed light on earthquake mechanisms and thus, indirectly help to assess societal risk. ICDP recovered such materials in compressional (Chelungpu, Taiwan), strike-slip (San Andreas, USA) and extensional systems (Gulf of Corinth, Greece). In this proposal, we suggest the development of a heated (up to 200-250°C), back-pressured direct shear apparatus where such fault gouges may be tested at up to 200 MPa normal stress. It will offer a wide range of opportunities to precisely measure rate-dependent frictional strength of sediments and rocks, transients of pore pressure and permeability during loading, failure, and shear movement, and dilatancy versus shear-enhanced compaction and strengthening at the known or inferred in situ conditions. The major focus will be the SAFOD project, as new core is recovered at this moment. It will be complemented by material from the Nobeaka and Nojima faults, rocks from the Shimanto Belt or the Franciscan Complex (to cover a wide temperature spectrum going as high as ca. 350°C), and exhumed rocks from slab break-off on Crete (also a potential ICDP drill site). As a mid-term perspective, the results can be compared to important marine equivalents such as major decollement gouges at the Nankai Trough (to be recovered within IODP with DV Chikyu) and elsewhere, and hence link the two scientific drilling programs in the continental and marine realm.