RAPID/Collaborative Research: Advancing Probabilistic Fault Displacement Hazard Assessments by Collecting Perishable Data from the 2023 Turkiye Earthquake Sequence

RAPID/合作研究：通过收集 2023 年土耳其地震序列的易腐烂数据推进概率断层位移危险评估

• 批准号: 2330153
• 负责人: Clinton Wood
• 金额: $ 5万
• 依托单位: University of Arkansas
• 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: 2023-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2330153&HistoricalAwards=false
• 关键词: RAPID; Collaborative; Research; Advancing; Probabilistic

The 300-km-long magnitude (M) 7.8 earthquake rupture along the East Anatolian Fault in Türkiye is one of the largest strike-slip ruptures instrumented globally. At the same time, the 150-km-long M7.5 rupture of the largest aftershock on the Sürgü fault, produced surface displacements on the order of 8 m, exceeding, on average, the displacement-length relations used for the 2023 National Seismic Hazard Model (NSHM) update by more than fifty percent. These ruptures share a similar tectonic setting with the San Andreas Fault System (SAFS) in California, so evaluating the NSHM by comparison with the Türkiye fault ruptures is important in the context of risk reduction in the US. A similar rupture on the SAFS, often referred to as 'The Big One' in California, will threaten the population and economy of major urban centers, national defense installations, and other critical infrastructures. Observing and documenting displacements along these exceedingly long and rare ruptures is therefore critical to understanding and reproducing earthquake rupture processes, empirically and numerically; to reducing uncertainty in regional hazard models; and reducing the risk of distributed infrastructure systems that are vital to the health and prosperity of communities, and vulnerable to ground deformation, such as water and gas pipelines. Findings and open-source datasets from this Grant for Rapid Response Research (RAPID) fieldwork will guide public policy and engineering design codes through future improvements of the NSHM, as well as decision makers for a greater extent of societal well-being and national defense. To complete this work, partnerships between academia and government agencies in both the US and Türkiye have been established; the team is diverse and includes a balance of early-career scientists and senior scientists, geotechnical earthquake engineers and earthquake geologists, US-based and in-country collaborators, and scientists from underrepresented backgrounds. The intellectual merit of this work lies in setting a new paradigm in fault rupture field mapping for engineering applications. While there is field, laboratory and numerical evidence that shallow geological conditions affect fault displacements, the evidence is at best qualitative, and thus the documented data cannot be integrated in engineering models for risk reduction. In order to capture these effects in predictive empirical models for engineering applications, new kind of dataset is needed that associates each fault displacement measurement site with geotechnical site characterization measurements. The primary field objectives include characterization of the 2023 ruptures by means of: (1) mapping the main fault rupture with high-resolution (cm-scale) GNSS surveys, photographs, ground-based lidar, and UAV-based terrain models, (2) documenting discrete and perishable offsets of cultural and geomorphic features, (3) characterizing the width and style of the deformation zone, (4) accompanying the measurements of the transient deformation zones with dynamic site characterization measurements on a sub-km scale using active source and ambient wavefield surface wave methods, along with horizontal to vertical spectral ratio (HVSR) measurements, (5) providing geological context (e.g., dominant geological processes and depositional units) for site characterization efforts, and (6) identifying secondary effects such as gravitational failures and liquefaction. Insights and scaling behaviors stemming directly from the field data will provide the first of what is envisioned to constitute the next-generation fault displacement datasets that will allow future PFDHA models to capture repeatable effects associated with local geologic conditions and fault geometry among other parameters.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.

土耳其东部安纳托利亚断层沿线发生的 300 公里长的 7.8 级地震破裂是全球监测到的最大的走滑破裂之一，同时也是最大的 150 公里长的 M7.5 破裂。 Sürgü 断层上的余震产生了约 8 m 的地表位移，平均超过了用于2023 年国家地震灾害模型 (NSHM) 更新了 50% 以上，这些断裂与加利福尼亚州的圣安德烈亚斯断层系统 (SAFS) 具有相似的构造环境，因此通过与 Türkiye 断层断裂进行比较来评估 NSHM 非常重要。 SAFS 的类似破裂（在加利福尼亚州通常被称为“大事件”）将威胁主要城市中心的人口和经济以及国防。因此，观察和记录这些极长且罕见的破裂过程对于从经验和数值上理解和再现地震破裂过程至关重要；对社区的健康和繁荣至关重要，并且容易受到地面变形的影响，例如水和天然气管道。快速响应研究补助金 (RAPID) 实地工作的调查结果和开源数据集将指导公共政策和工程。通过 NSHM 的未来改进来设计规范，并为决策者提供更大程度的社会福祉和国防。为了完成这项工作，美国和土耳其的学术界和政府机构之间建立了合作伙伴关系；是多元化的，包括早期职业科学家和资深科学家、岩土地震工程师和地震地质学家、美国和国内合作者以及来自代表性不足背景的科学家。这项工作的智力价值在于设定了一个新的范式。虽然有现场、实验室和数值证据表明浅层地质条件影响断层位移，但这些证据最多是定性的，因此记录的数据无法集成到工程模型中以降低风险。为了在工程应用的预测经验模型中捕获这些影响，需要一种新的数据集，将每个断层位移测量站点与岩土站点特征测量相关联，主要的现场目标包括通过以下方式表征 2023 年破裂。主要的使用高分辨率（厘米级）GNSS 勘测、照片、地面激光雷达和无人机地形模型来确定断层破裂，(2) 记录文化和地貌特征的离散和易消失的偏移，(3) 描述宽度和类型(4) 使用主动源和环境波场表面波方法以及水平与垂直谱比，对瞬态变形区进行伴随测量，并进行亚公里尺度的动态场地特征测量（HVSR）测量，（5）为场地表征工作提供地质背景（例如，主要地质过程和沉积单元），以及（6）确定直接来自现场数据的重力破坏和液化等次要影响和建模行为。将提供第一个构建下一代断层位移数据集的设想，该数据集将使未来的 PFDHA 模型能够捕获与当地地质条件和断层几何形状以及其他参数相关的可重复影响。该奖项反映了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，NSF 的法定使命被认为值得支持。