Collaborative Research: Active deformation and exhumation at the transition from subduction to oblique collision in Central New Zealand

合作研究：新西兰中部俯冲到斜碰撞过渡过程中的主动变形和折返

• 批准号: 2313490
• 负责人: Colin Amos
• 金额: $ 26.4万
• 依托单位: Western Washington University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2313490&HistoricalAwards=false
• 关键词: Collaborative; Research; Active; deformation; exhumation

Earth’s outer shell consists of rigid tectonic plates that interact primarily along their edges. Several factors control these interactions, including the composition of the plates (oceanic versus continental) and the relative sense of motion between them (colliding, diverging, or sliding past one another). These factors combined control the natural hazards expressed along tectonic plate boundaries, including earthquakes, landslides, tsunamis, and volcanoes. Because Earth’s tectonic plates are not static, the distribution and character of tectonic plate boundaries change over geologic time. As such, understanding plate-boundary hazards requires a comprehensive view of their evolution in response to changes in plate motions and character. The 2016 M7.8 Kaikōura earthquake in Aotearoa New Zealand occurred at a critical plate tectonic transition zone, where the boundary changes from subduction (oceanic plate consumed beneath continental) to strike slip (sliding parallel to one another) and ultimately continental collision. The extent of deformation and triggered landslides in this event highlight the complex hazards associated with a major plate-boundary transition. This study will shed light on how plate transitions evolve by studying active faults and cooling ages of uplifted bedrock in the area surrounding the 2016 earthquake. Impacts of this study include advancing scientific knowledge and training graduate students, thereby contributing to a globally competitive scientific workforce. The project bolsters domestic and international partnerships by engaging US students in collaborative, international field work, and deepens connections between US and New Zealand researchers. The investigators will develop an international university seminar series focused on exploring bicultural approaches to weaving indigenous knowledge and geoscience research. With New Zealand collaborators and Māori advisors at the University of Canterbury, the investigators will build on their institutional connections to indigenous and minoritized communities to broaden participation of these groups both in the seminar and in geological field research. Finally, this project will enhance research and educational infrastructure by supporting new and existing analytical capacities at Western Washington University and the University of Michigan.This project focuses on the evolution of crustal deformation across a plate-boundary transition from subduction to oblique collision through collection and integration of new neotectonic and low-temperature thermochronologic data in North Canterbury, New Zealand. Specific research tasks include: (1) characterizing the rate and kinematics of shallow faulting for understudied structures surrounding the epicentral region of the 2016 Kaikōura earthquake, (2) measuring differential uplift from incised fluvial surfaces along major rivers transecting fault-related folds in this area, and (3) quantifying the onset, rate, and spatial pattern of bedrock exhumation associated with the transition from subduction to oblique collision. These tasks target existing knowledge gaps related to the mechanics and kinematics of plate boundary migration, and will shed light on outstanding research questions including: How do plate-boundary terminations migrate over time, and what are the fault growth mechanisms through which a new plate-boundary structure develops? Is there a measurable “bow wave” or “wake” attending this migration that impacts crustal deformation and exhumation? What is the role of the subducting slab in controlling deformation at a subduction termination over multiple earthquake cycles?This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

地球的外壳由刚性构造板块组成，这些板块主要沿着其边缘相互作用，有几个因素控制着这些相互作用，包括板块的组成（海洋板块与大陆板块）以及板块之间的相对运动感（碰撞、发散或相互滑过）。这些因素共同控制了沿板块边界的自然灾害，包括地震、山体滑坡、海啸和火山，因为地球的板块不是静态的，其分布和特征也是如此。因此，了解板块边界灾害需要全面了解板块运动和特征变化对板块边界的影响。 2016 年新西兰奥特亚罗瓦 M7.8 凯库拉地震发生在一个关键的板块构造时期。过渡区，边界从俯冲（海洋板块在大陆下方消耗）转变为滑动走向（彼此平行滑动），并最终发生大陆碰撞的程度。此次事件中的山体滑坡凸显了与主要板块边界转变相关的复杂危害。这项研究将通过研究 2016 年地震周围地区隆起基岩的活动断层和冷却年龄来揭示板块转变的演变过程。该项目通过让美国学生参与国际合作实地工作，促进国内和国际合作，并加深美国和新西兰研究人员之间的联系。大学系列研讨会的重点是探索将土著知识和地球科学研究结合起来的双文化方法，研究人员将与新西兰合作者和坎特伯雷大学的毛利顾问一起，建立他们与土著和少数民族社区的机构联系，以扩大这些群体对地球科学研究的参与。最后，该项目将通过支持西华盛顿大学和密歇根大学新的和现有的分析能力来加强研究和教育基础设施。该项目的重点是板块边界转变过程中地壳变形的演化。通过收集和整合新西兰北坎特伯雷的新新构造和低温热年代学数据，研究俯冲到倾斜碰撞的具体研究任务包括：（1）表征2016年震中区域周围未研究构造的浅层断层运动的速率和运动学。凯库拉地震，(2) 测量该地区横断断层相关褶皱的主要河流沿线切割河流表面的差异隆起，以及 (3) 量化这些任务针对与板块边界迁移的力学和运动学相关的现有知识差距，并将阐明突出的研究问题，包括：板块如何运动。 -边界终端随着时间的推移而迁移，新的板块边界结构发展的断层生长机制是什么？是否存在可测量的“弓波”或“尾流”参与这种影响地壳变形和折返的迁移？俯冲板片在控制多个地震周期俯冲终端变形方面的作用是什么？该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。