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

PI团队将在日本纪井半岛南部熊野盆地地区获取、处理和解释高质量的三维地震反射数据。三维地震调查将于2006年4月由PGS船R/V Ramform Victory（挪威注册）进行，由NSF和JAMSTEC联合支持。这些数据将定义构成发震区上倾端的多个断层的基本几何、历史和物理性质，其中许多断层在1944年的8.1级托南开地震中破裂。拟议的工作是综合南开槽孕震带实验（NanTroSEIZE）的主要组成部分，包括最近排名较高的浅层无隔水管钻井和综合海洋钻井计划（IODP）计划的深隔水管钻井。通过钻井和相关的钻孔地球物理实验，这个三维地震体将为板块边界断层系统提供前所未有的照明，以可视化其几何形状、历史和相关的岩石性质，因为它向下倾斜演变成一个地震带。此外，3D成像和地震属性映射是优化钻井地点和详细规划钻井和套管作业的重要组成部分，为有史以来最雄心勃勃的科学海洋钻井作业提供支持。该项目由四家美国机构和两家日本机构合作，与一家地震公司签订合同，收集并提供一个20x80公里的三维地震反射网格的初步处理，该网格沿着熊野盆地到南开增积棱镜的锋面推进的样带。这项研究包含了许多更广泛的影响，包括更好地了解危险俯冲带逆冲地震起源的社会效益。

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.