Collaborative Research: Structural-Petrologic Characterization of the San Andreas Fault in the SAFOD Drill Holes

0454527埃文斯SAFOD的科学目标是了解活动板块边界断层内变形和地震生成的物理和化学过程。只有彻底记录断裂带的结构和地球化学，并与其他数据相结合，才有可能全面了解断裂带。这一合作努力将表征天文台圣安德烈亚斯断层的组成，结构和变形机制。从先导孔和前两个阶段的钻探（2004-2005年）的岩心和岩屑的观察，以及从钻探现场附近的断层暴露的样本，将与其他SAFOD研究中提供的地球物理和水文数据相结合，以解决有关断层的结构，物理性质和力学的关键问题，并测试地震破裂动力学，能量平衡和断层弱化的假设。工作包括确定断层岩的岩性、裂缝的分布和方向、次级断层、矿脉和粒度，并针对关键结构进行详细的微观结构、矿物学和地球化学分析。

0454527EvansThe scientific objective of SAFOD is to understand the physical and chemical processes ofdeformation and earthquake generation within an active, plate-bounding fault. Comprehensiveunderstanding will be possible only if the structure and geochemistry of the fault zone arethoroughly documented and integrated with other data. This collaborative effort will characterizethe composition, structure and deformation mechanisms of the San Andreas fault at theObservatory. Observations of core and cuttings from the pilot hole and first two phases of drilling(2004-2005), and of samples from fault exposures near the drill site, will be integrated withgeophysical and hydrologic data presented in other SAFOD studies to address key questionsregarding structure, physical properties and mechanics of the fault, and to test hypotheses ofearthquake rupture dynamics, energy balance, and fault weakening. Work includes determiningfault rock lithology, and distributions and orientations of fractures, secondary faults, veins, andparticle sizes, and targeting key structures for detailed microstructure, mineralogy, andgeochemistry analyses.