Collaborative Research: Paleoseismology of the M7.3 1915 Pleasant Valley Earthquake Ruptures

合作研究：1915 年 M7.3 普莱森特谷地震破裂的古地震学

• 批准号: 1920514
• 负责人: Steven Wesnousky
• 金额: $ 22.14万
• 依托单位: Board of Regents, NSHE, obo University of Nevada, Reno
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1920514&HistoricalAwards=false
• 关键词: Collaborative; Research; Paleoseismology; M7.3; 1915

This project to use geology to assess the past size and frequency of occurrence of large earthquakes on the fault that produced the magnitude 7.3 1915 Pleasant Valley earthquake in Nevada forms the underpinnings of a collaborative program of science, education and outreach. It is through the cumulative study of individual earthquakes that the research community gains observations to understand earthquake ruptures and their role in active tectonic processes. The information gained in this project will be incorporated into the National Hazard Maps designed to reduce failure of building infrastructure and lifelines and loss of life in future earthquakes. The collaboration of three institutes is designed to provide the opportunity for undergraduate and graduate students to learn methods and concepts bearing on earthquake science in the framework of an active research project, lead to the development of online and classroom materials for education and research, create links between rural Nevada college campuses and the University of Nevada, Reno. Principal investigators at two of the three participating institutions are early career female researchers.The study will consider one of the few large continental earthquakes that occurred in recent history and remove a significant void in our collective understanding of active tectonics in the Basin and Range and the Central Nevada Seismic Belt. This research will quantify the timing of past earthquakes and the average rate of slip on the fault that produced the Mw 7.3 1915 earthquake. The use of modern Accelerator Mass Spectrometry radiocarbon, Optical Stimulated Luminescence, and Terrestrial Cosmogenic dating methods in conjunction with paleoearthquake trenching investigations proposed herein will yield observations to 1) assess the northward extent to which slip rate is elevated along the Central Nevada Seismic Belt within the interior of the Basin and Range, 2) to determine whether the past history of events in Pleasant Valley exhibits repeated clustering of events that is observed in the Central Nevada Seismic Belt to the south, 3) address whether or not strands of the 1915 rupture separated by a 4 kilometer step in trace exhibited the same behavior in past earthquakes, 4) compare geologic rates of slip during the late Pleistocene as compared to modern geodesy, 5) cross-check multiple dating techniques applied to the same sediments, and 6) develop quantitative constraints on the timing of alluvial fan deposition in Pleasant Valley as a possible tool for assessing fault slip rates on adjacent range fronts exhibiting the same geomorphic and soil characteristics. In sum, there are few continental normal fault earthquake ruptures on which to gather observations bearing on the characteristics of rupture and recurrence. This study will provide the basis to compare and contrast characteristics of the 1915 ruptures to those that occurred before, both on the 1915 fault and elsewhere around the globe. The data collected will place observational bounds on conceptual models of earthquake recurrence and the physics of earthquake processes that form the underpinnings of seismic hazard analysis.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.

这个项目利用地质学来评估发生在1915年内华达州普莱森特谷7.3级地震的断层上的大地震过去的规模和发生频率，形成了科学、教育和推广合作项目的基础。通过对单个地震的累积研究，研究团体获得了观测结果，以了解地震破裂及其在活动构造过程中的作用。在这个项目中获得的信息将被纳入国家灾害地图，旨在减少未来地震中建筑基础设施和生命线的损坏和生命损失。三个研究所的合作旨在为本科生和研究生提供机会，在一个活跃的研究项目框架内学习与地震科学有关的方法和概念，促进教育和研究的在线和课堂材料的开发，在内华达州农村大学校园和内华达大学里诺分校之间建立联系。在三个参与机构中，有两个机构的首席研究员是早期职业女性研究人员。这项研究将考虑近代历史上发生的为数不多的大型大陆地震之一，并消除我们对盆地和山脉以及内华达中部地震带活动构造的集体理解中的一个重要空白。这项研究将量化过去地震的时间和产生1915年7.3级地震的断层的平均滑动率。利用现代加速器质谱法、放射性碳法、光学激发发光法和地球宇宙生成测年法，结合本文提出的古地震沟调查，将产生以下观测结果：1)评估沿盆地和山脉内部内华达中部地震带向北滑移率升高的程度；2)确定普莱森特谷过去的历史事件是否显示了在南部内华达中部地震带观察到的重复聚集事件，3)确定1915年的断裂链是否在过去的地震中表现出相同的行为，4)将晚更新世的地质滑动率与现代大地测量相比较，5)交叉检查应用于同一沉积物的多种测年技术，6)对Pleasant Valley的冲积扇沉积时间进行定量约束，作为评估具有相同地貌和土壤特征的相邻山脉前缘断层滑动率的可能工具。总而言之，很少有大陆正断层地震破裂可以收集到与破裂和复发特征有关的观测资料。这项研究将为1915年断层和全球其他地方的断裂特征与之前发生的断裂特征进行比较和对比提供基础。收集到的数据将为地震复发的概念模型和地震过程的物理学提供观测范围，这些模型是地震危害分析的基础。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。