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.

沿土耳其东安纳托利亚断层沿着的300公里长的7.8级地震破裂是全球观测到的最大的走滑破裂之一。与此同时，苏尔古断层上最大余震的150公里长的M7.5破裂产生了8米量级的地表位移，平均超过了2023年国家地震危险模型（NSHM）更新所使用的位移-长度关系的50%以上。这些断裂与加州的圣安德烈亚斯断层系统（SAFS）具有相似的构造背景，因此，在美国降低风险的背景下，通过与土耳其断层断裂进行比较来评估NSHM非常重要。在加州，SAFS上的类似破裂通常被称为“大破裂”，将威胁到主要城市中心的人口和经济、国防设施和其他关键基础设施。因此，观察和记录这些极长且罕见的断裂带的位移沿着对于以下方面至关重要：从经验和数字上理解和再现地震断裂过程;减少区域灾害模型的不确定性;以及减少分布式基础设施系统的风险，这些基础设施系统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。来自快速反应研究（RAPID）现场工作的研究结果和开源数据集将通过NSHM的未来改进指导公共政策和工程设计规范，以及决策者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;该团队是多元化的，包括早期职业科学家和高级科学家，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建立一个新的范例，断层破裂场映射的工程应用。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，证据充其量是定性的，因此，记录的数据不能集成在工程模型中，以减少风险。为了在工程应用的预测经验模型中捕获这些影响，需要将每个断层位移测量站点与岩土站点表征测量相关联的新型数据集。主要现场目标包括通过以下方式对2023年断裂进行表征：（1）高分辨率绘制主断层破裂图（厘米级）全球导航卫星系统调查、照片、地面激光雷达和无人机地形模型，（2）记录文化和地貌特征的离散和易消失的偏移，（3）描述变形带的宽度和风格，（4）伴随瞬态变形区的测量，使用有源和环境波场表面波方法，沿着水平与垂直频谱比（HVSR）测量，进行亚公里尺度的动态场地表征测量，（5）提供地质背景（例如，主要地质过程和沉积单元），用于场地表征工作，以及（6）识别重力破坏和液化等次级效应。直接来自现场数据的见解和缩放行为将提供第一个设想构成下一个-生成断层位移数据集，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NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准。