Collaborative Research: A 3-D Seismic Investigation of the Nankai Trough Plate Boundary System in the Kumano Basin

PI团队将获取、处理和解释日本纪伊半岛南部熊野盆地地区的高质量三维地震反射数据体。三维地震调查将于2006年4月由PGS船R/V Ramform Vicary(挪威注册处)进行，由NSF和JAMSTEC联合支持。这些数据将确定构成孕震带上倾端的多条断层的基本几何、历史和物理性质，其中许多断层在1944年托南凯8.1级地震中破裂。这项拟议的工作是南开海槽综合孕震带实验(NantroSEIZE)的主要组成部分，包括最近排名较高的浅部无立管钻探和通过综合大洋钻探计划(IODP)计划的深部立管钻探。通过钻探获得的地面真实资料和相关的钻孔地球物理实验，这一3D地震体将提供前所未有的板块边界断层系统的照明，以可视化其几何形状、历史和相关的岩石属性，因为它向下倾斜演化为地震孕育区。此外，3D成像和地震属性绘图是细化钻探现场位置和详细规划钻井和套管作业的重要组成部分，以支持有史以来最雄心勃勃的科学海洋钻探作业。该项目是四个美国和两个日本机构的合作努力，目的是与一家地震公司签约，收集和提供从熊野盆地到南开吸积棱镜前缘推覆的断面上约20x80公里的三维地震反射网格的初步处理。这项研究涵盖了一些更广泛的影响，包括更好地了解危险的俯冲带逆冲地震的起源所带来的社会益处。

AbstractThe PI team will acquire, process, and interpret a high-quality 3-D seismic reflection data volume in the Kumano Basin region south of Kii Peninsula, Japan. The 3D seismic survey will be carried out in April 2006 by PGS ship R/V Ramform Victory (Norwegian registry), jointly supported by the NSF and JAMSTEC. These data will define the fundamental geometry, history and physical properties of the multiple faults that compose the up-dip end of the seismogenic zone, many of which ruptured in the 1944 M 8.1 Tonankai earthquake. The proposed work is a major component of the integrated Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE), including the recently highly ranked shallow non-riser drilling and the deep riser drilling planned through the Integrated Ocean Drilling Program (IODP). With ground-truth from drilling and associated borehole geophysical experiments, this 3D seismic volume will provide unprecedented illumination of a plate boundary fault system to visualize its geometry, history, and associated rock properties, as it evolves down dip into a seismogenic zone. Furthermore, 3D imaging and seismic attribute mapping are essential components for refining drill site locations and for detailed planning for drilling and casing operations in support of the most ambitious scientific ocean drilling operation ever conceived. This project is a collaborative effort among four U.S. and two Japanese institutions to contract a seismic company to collect and provide preliminary processing of an ~20x80 km 3-D seismic reflection grid, along a transect from the Kumano Basin to the frontal thrust of the Nankai accretionary prism. The study encompasses a number of broader impacts, including the societal benefit of better understanding the origin of dangerous subduction zone thrust earthquakes.