GOUGE - Hydrothermal deformation experiments on ICDP fault zone materials

从孕震区钻探中获得的断层泥可以揭示地震机制，从而间接帮助评估社会风险。ICDP在挤压（台湾车笼埔）、走滑（美国圣安德烈亚斯）和伸展系统（希腊科林斯湾）中回收了此类物质。在本提案中，我们建议开发一种加热（高达200-250°C）、背压式直接剪切仪，在该仪器中，可以在高达200 MPa的正应力下测试此类断层泥。它将提供广泛的机会，精确测量沉积物和岩石的速率相关的摩擦强度，加载过程中的孔隙压力和渗透率的瞬变，故障，剪切运动，以及在已知或推断的原位条件下的剪切增强压实和强化的粘性。主要重点将是SAFOD项目，因为此时正在回收新的核心。它将补充来自Nobeaka和Nojima断层的材料，来自Shimanto带或Franciscan Complex的岩石（以覆盖高达约1000 ℃的宽温度谱）。350°C），以及从克里特岛（也是一个潜在的ICDP钻探地点）的板断裂中挖掘出来的岩石。从中期角度来看，这些结果可以与重要的海洋等效物进行比较，例如南海海槽（将在IODP内与DV Chikyu一起恢复）和其他地方的主要滑脱断层泥，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.