Seismological studies of plate tectonic boundaries and rifted margins

板块构造边界和裂谷边缘的地震学研究

• 批准号: RGPIN-2020-05562
• 负责人: Nedimovic, Mladen
• 金额: $ 4.44万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=750949
• 关键词: Seismological; studies; plate; tectonic; boundaries

The proposed research program is focused on plate boundaries and major transition zones in the Earth's solid outer layer, the lithosphere. The plate boundaries under investigation, namely subduction zones, mid-ocean ridges and transform faults, as well as the continent-ocean transitions found at rifted margins and internal to the plates, all form as part of the Earth's plate tectonic cycle. Subduction zones are places where oceanic and continental plates converge, where the thinner but denser oceanic plate sinks under the continental plate to eventually recycle into the Earth's mantle, and where the largest earthquakes on Earth occur. At transform margins, plates slide past one another, producing earthquakes with magnitudes second only to those occurring on subduction thrusts. Mid-ocean ridges are divergent plate tectonic boundaries where new oceanic crust is continuously generated. They make up the most extensive mountain system and the longest chain of volcanoes on Earth. Rifted continental margins form by extension and breakup of the continental lithosphere, a process that creates new ocean basins. The proposed research program will apply state-of-the-art data analysis methods to active and passive source seismic data. The goal is to investigate the targeted subsurface structures at unprecedented resolution in order to test leading scientific hypotheses and answer questions that have the potential to transform our understanding of plate boundaries. The selected study areas are: Cascadia Subduction Zone, Queen Charlotte Fault, Southwest Indian Ridge, and Western Baffin Bay. The study areas and problems to be addressed are chosen based on their suitability for achieving my short- and long-term science goals, the potential for high-impact discoveries, their economic and societal impacts, and interest to a broad group of earth scientists and general public. Earthquakes and the associated tsunamis, as well as volcanic eruptions pose significant hazards to Canadians and our infrastructure. Improved constraints on the geometry and character of seismogenic zones and seismicity in general, an anticipated outcome of the planned research, will lead to more accurate probabilistic seismic hazards maps and improved building codes. These are the primary means used to mitigate earthquake damage. New constraints on the deep structures at rifted margins, which host the largest recently drilled hydrocarbon deposits, will help guide future exploration. All of the projects that comprise the proposed research program are high-profile international collaborations because investigations of structures deep below the seabed, which is one of the Earth's last frontiers, require major resources, both human and technological. This cutting-edge collaborative environment presents an excellent opportunity to train HQP that will one day lead the next generation of researchers to new discoveries.

拟议的研究计划的重点是板块边界和地球固体外层岩石圈的主要过渡区。所研究的板块边界，即俯冲带、洋中脊和转换断层，以及在断裂边缘和板块内部发现的大陆-海洋过渡带，都是地球板块构造循环的一部分。俯冲带是海洋板块和大陆板块汇聚的地方，在那里，较薄但密度较大的海洋板块下沉到大陆板块之下，最终再循环进入地幔，地球上最大的地震发生在那里。在转换边缘，板块相互滑动，产生的地震震级仅次于俯冲逆冲断层。洋中脊是发散的板块构造边界，新的洋壳在这里不断生成。它们构成了地球上最广阔的山脉系统和最长的火山链。裂断大陆边是大陆岩石圈的伸展和断裂形成的，这一过程产生了新的洋盆。拟议的研究计划将采用最先进的数据分析方法，主动和被动源地震数据。其目标是以前所未有的分辨率调查目标地下结构，以测试领先的科学假设，并回答有可能改变我们对板块边界理解的问题。选定的研究区域是：卡斯卡迪亚俯冲带，夏洛特女王断层，西南印度洋脊和西巴芬湾。要解决的研究领域和问题的选择是基于它们是否适合实现我的短期和长期科学目标，高影响力发现的潜力，它们的经济和社会影响，以及对地球科学家和公众的广泛兴趣。地震和相关的海啸以及火山爆发对加拿大人和我们的基础设施构成重大危险。改善对孕震区和地震活动性的几何形状和特征的限制，这是计划研究的预期成果，将带来更准确的概率地震灾害地图和更好的建筑规范。这些是用于减轻地震破坏的主要手段。裂谷边缘的深层构造存在着最近钻探的最大的碳氢化合物矿床，对这些构造的新限制将有助于指导未来的勘探。包括拟议研究计划在内的所有项目都是备受瞩目的国际合作，因为对海底深处结构的调查是地球最后的前沿之一，需要大量的人力和技术资源。这种尖端的协作环境为培养HQP提供了绝佳的机会，有朝一日，HQP将带领下一代研究人员取得新的发现。