CAREER: Does long-term topography preserve details of the seismic cycle? Seeing through, and exploiting, the diverse forcings influencing actively deforming landscapes.

职业：长期地形是否保留了地震周期的细节？

• 批准号: 2237437
• 负责人: Adam Forte
• 金额: $ 47.55万
• 依托单位: Louisiana State 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: 2023-06-01 至 2028-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2237437&HistoricalAwards=false
• 关键词: CAREER; Does; long; term; topography

The shape of topography in tectonically active regions reflects a balance between the uplift of rocks from tectonic forces and the removal of rock and sediment by erosive forces, the latter of which are mediated by the local details of the climate and the types of rocks exposed. If the climatic and rock type details are constrained, then aspects of topography, like the shape of rivers, can serve as proxies for details of the tectonic forces and reveal, for example, the location and relative activity of faults. While providing critical insight into active tectonics, these approaches tend to idealize rock uplift along faults as a steady process. However, in reality rock uplift and the growth of topography usually occurs through more punctuated processes, specifically long periods of slow distributed deformation between earthquakes and then sudden and violent deformation during earthquakes, which combined over millennia, result in the integrated and idealized average rock uplift. The extent to which details of this “seismic cycle” are preserved in topography is unclear, but unlocking potential records stored in topography would be transformative as it could provide insight into specifics critical for hazard assessments, like average time between earthquakes and the relative extents of earthquake ruptures, through relatively quick, easy, and cheap analyses from globally available topography data. This project explores the preservation potential of aspects of the seismic cycle through a two-pronged approach. First, a large and comprehensive suite of simulations of landscapes developing through successive earthquake events and with varying climate and lithology details are being used to develop a set of fingerprints for relating landscape form to earthquake details. Secondly, these fingerprints are being applied to regions with independently established histories of fault and earthquake activity to vet and refine the results from the simulations. The broad goal of this research is providing a critical set of tools for better understanding earthquake hazards, both domestically and abroad in regions that lack comprehensive seismic hazard assessments and improve the safety and security of populations living in regions of potential hazard. In addition to the research goals of this project, a set of unique educational tools to provide resources for understanding the ways in which topography more generally reflects the shaping tectonic and climatic forces is being developed. The results of this effort include a LandscapeLibrary, a large set of landscape simulations developed under a wide array of controlled conditions, which will be made available to the public through an interactive web interface. Additionally, a series of educational exercises which use the LandscapeLibrary are being developed for a range of education levels from secondary to graduate level, providing a far-reaching educational resource that will contribute to development of the STEM workforce and promote general understanding of the critical context for the surface of the Earth.Fundamental details of the tectonic history of actively deforming regions are encoded in their fluvial topography, but interpreting these histories requires full consideration of the array of forcing mechanisms contributing to their form. For example, significant prior work focused on the influence of spatially or temporally variable precipitation, variations in lithologic resistance to erosion, or autogenic processes within catchments, amongst others in complicating, the interpretation of tectonics from topography and the extent to which these additional forcings can be factored out and a meaningful tectonic signal can still be reliably extracted from fluvial topography. The tectonic signals interpreted from this topography typically are first-order characteristics of fault systems, e.g., the location and relative activity of major structures, their subsurface geometries, or temporal changes in their average slip rates, but which largely treat the deformation on faults, and resulting patterns in rock uplift driving topographic development, simplistically as rigid block motion. However, fault motion typically occurs seismically and with significant spatial variability in surface deformation within a single seismic cycle, and indeed, likely between seismic cycles driven by interseismic creep on non-locked portions of fault and strain accumulation on locked portions of faults which is released coseismically. The extent to which the seismic cycle influences the development of topography is fundamentally unknown, but a general assumption is that it can be safely ignored, and that topography reflects average slip rates and associated rates of rock uplift. However, some work has questioned this assumption, specifically whether a signal of incomplete recovery of interseismic strain by earthquakes may leave a signal in topography. More broadly, it remains unclear whether topography can record any details of the seismic cycle, but it is hypothesized in this project that it may, specifically because of interactions between the seismic cycle and other forcing mechanisms, such as spatially and temporally variable precipitation. This project is testing this hypothesis with an integrated modeling study coupled with a large-scale topographic analysis effort. Specifically, the project seeks to 1) use coupled surface processes and deformation models that simulate interseismic and coseismic deformation to identify topographic signatures of the seismic cycle and 2) assess whether these signals are recognizable in natural landscapes with independent constraint on at least parts of their seismic cycles. The project will provide crucial insight into the connections between the long-term topography developed in active deforming regions and short-term earthquake processes, which is a long-standing goal within both the tectonics and earth surface processes communities. This project follows recent efforts that attempt to use the topographic characteristics of simulated landscapes to extract more quantitative information from topography directly, e.g., estimation of slip rate magnitudes, but promises to extend our view to details of the seismic cycle and fault behavior. These details of the seismic cycle are a fundamental input for seismic hazard analysis, which is of great societal relevance, but extracting this critical information is often challenging, laborious, and expensive. As such, being able to assess even broad information about the seismic cycle of a fault system from something as ubiquitous and globally accessible as topography would be incredibly beneficial - and is a potential outcome from the proposed work. This effort will occur in tandem with the development of a large body of precomputed synthetic landscapes developed under diverse forcing conditions to build the LandscapeLibrary and an interface for easy access and visualization of this library. This resource, and educational materials developed with it, are designed to help provide an easy visual representation of landscape evolution for a variety of classroom purposes. The LandscapeLibrary will provide an invaluable resource for other geoscientist educators around the world who wish to provide their students an intuitive view of the diverse forcing on landscape evolution. Finally, this project will support one PhD student and a postdoctoral researcher.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.

构造活性区域中地形的形状反映了构造力量的岩石升高与侵蚀力量岩石和沉积物之间的平衡，后者是由气候的局部细节与暴露的岩石类型所介导的。如果气候和岩石类型的细节受到限制，那么地形的各个方面，例如河流的形状，可以作为构造力细节的代理，并揭示了例如故障的位置和相对活动。在对主动构造学的重要洞察力的同时，这些方法倾向于将沿断层的岩石提升为稳定的过程。然而，实际上，摇滚的隆起和地形的生长通常是通过更具标点的过程发生的，特别是地震之间地震之间的长时间较长的分布变形，然后在地震期间突然而剧烈的变形，这在数千年中结合在一起，导致整合和理想化的平均岩石提升。在地形中保留了这种“地震循环”的细节在多大程度上尚不清楚，但是在地形中存储的潜在潜在记录将具有变化性，因为它可以提供对危害评估至关重要的细节，例如地震之间的平均时间和地震中的平均时间和相对较快，易于较快，易于且可用的全球可用的超出性层表数据的廉价分析。该项目通过两管齐下的方法探索了地震周期方面的保护潜力。首先，通过成功的地震事件以及各种气候和岩性细节开发的景观的大量模拟套件已被用来开发一套指纹，以将景观形式与地震细节联系起来。其次，这些指纹应用于具有独立的断层和地震活动史的区域，以兽医和改进模拟结果。这项研究的广泛目标是提供一组关键的工具，以更好地理解地震危害，这是在缺乏全面的地震危险评估的地区，并改善了生活在潜在危险地区的人群的安全和安全性。除了该项目的研究目标外，还提供了一系列独特的教育工具，可提供资源以理解地形通常反映构成构造和民事力量的方式。这项工作的结果包括在广泛的受控条件下开发的大量景观模拟，通过交互式Web界面向公众提供。此外，正在为从次级到研究生水平的一系列教育水平开发一系列使用景观的教育练习，提供了深远的教育资源，这将有助于STEM劳动力的发展，并促进对地球表面的关键环境的一般理解。强迫有助于其形式的机制。例如，重大的先前工作重点关注空间或暂时可变的降水，岩性抗侵蚀性的变化或流域内的自动源过程，以及其他方面的自动源过程，使构造学从地形学对构造学的解释以及这些其他强制性的概括和有意义的tectonic Signal的范围仍然可以相互介入，从而可以相互介绍。从该地形中解释的构造信号通常是故障系统的一阶特征，例如，主要结构的位置和相对活性，其地下几何形状或平均滑动速率的临时变化，但在很大程度上可以治疗故障的变形，以及在岩石上的摇摆地形开发中，刚性驱动的图形在刚性的固定块运动中，导致的模式。然而，断层运动通常在地震中发生，并且在单个地震循环中表面变形的空间变形显着，实际上，可能是在断层锁定部分的非锁定部分驱动的地震周期之间的地震循环之间的地震循环，并在断层的锁定部分上积累，这是释放出抗异害性的。地震周期影响地形的发展的程度从根本上是未知的，但是一个普遍的假设是可以安全地忽略它，并且地形反映了平均滑移速率和相关的岩石升高速度。但是，某些工作质疑这一假设，特别是地震恢复了穿刺菌株不完全恢复的信号是否可能在地形中留下信号。更广泛地说，尚不清楚地形是否可以记录地震循环的任何细节，但是在该项目中假设它可能是因为地震循环与其他强迫机制之间的相互作用，例如空间和暂时可变的降水。该项目正在通过一项集成的建模研究以及大规模的地形分析工作来检验这一假设。具体而言，该项目寻求1）使用耦合的表面过程和变形模型，这些模型模拟了经过震动和coseismisic变形，以识别地震周期的地形特征，以及2）评估这些信号在自然景观中是否在其地震周期的至少限制的自然景观中识别。该项目将提供至关重要的见解，了解在主动变形区域和短期地震过程中开发的长期地形之间的联系，这在构造和地面过程中都是社区中的长期目标。该项目遵循最近的努力，试图使用模拟景观的地形特征直接从地形中提取更多的定量信息，例如对滑移速率的估计，但有望将我们的观点扩展到地震周期和断层行为的细节。地震周期的这些细节是地震危害分析的基本意见，这是非常社会相关性的，但是提取这些关键信息通常受到挑战，实验室和昂贵的挑战。因此，能够从无处不在且全球访问的地形访问的事物中评估有关断层系统的地震周期的广泛信息，这是非常有益的 - 这是拟议中的潜在结果。这项工作将与在潜水员强迫条件下开发的大量预算合成景观的发展同时进行，以构建景观景观和界面，以便于访问和可视化该库。该资源以及用它开发的教育材料旨在帮助提供各种课堂目的的景观演化的视觉表现。 LandscapeLibrary将为世界各地的其他地球科学家教育提供宝贵的资源，他们希望为学生提供对潜水员对景观进化的强迫的直观看法。最后，该项目将支持一名博士生和一名博士后研究员。该奖项反映了NSF的法定任务，并通过使用基金会的知识分子优点和更广泛的影响审查标准来评估诚实地支持了支持。