Collaborative Research: Improving the Chronology of Deformation and Earthquakes at La Rinconada, Argentina: Testing Segmentation and Recurrence Patterns of Blind Thrust Regimes

合作研究：改进阿根廷拉林科纳达变形和地震的年代学：测试盲目推力机制的分段和重现模式

• 批准号: 0838344
• 负责人: Lewis Owen
• 金额: $ 3.91万
• 依托单位: University of Cincinnati Main Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-02-01 至 2010-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0838344&HistoricalAwards=false
• 关键词: Collaborative; Research; Improving; Chronology; Deformation

Understanding the earthquake potential of blind thrust faults (faults that do not reach the Earth?s surface) has major seismic hazard implications for heavily populated areas such as Los Angeles and Seattle in the United States as well as other population centers within seismically active regions around the World. Key questions regarding the long-term behavior of destructive earthquake faults include what are the size and frequency of earthquakes and how do those vary in time and space. Better knowledge of the timing and sizes of past earthquakes is essential information used to forecast future events, to characterize local and regional seismic hazards, and to inform the public and emergency planners. Heavily populated areas, however, are difficult to study because concrete, buildings, and development obscure the expression of active faults. In this study, an active fault system near San Juan Argentina, which bears structural similarities to blind faults within metropolitan regions in the United States, but has the advantage that the area is largely undisturbed, is being investigated to better understand the surficial expression and earthquake history of several active blind thrust faults. This project is focused on dating of a large suite of samples collected from river terraces and alluvium deformed and faulted by the earthquake faults. From these new data, the timing of the past five large earthquakes on the blind fault system will be established. The new age data will allow comparison with the earthquake history of nearby fault systems documented in earlier work, faults that were responsible for damaging earthquakes in 1944 and 1977 in the region. This project will test whether earthquake frequency on individual faults is quasi-periodic (and therefore predictable), whether these fault systems produce earthquakes that cluster in time, and test whether some past earthquake may have ruptured a larger source region or have been confined to the same source dimensions as the historical events. Like the results from an earlier phase of this project, the Argentinean collaborators and others will use the new results from this project to constrain seismic hazard, inform earthquake engineers, and educate the public about earthquake hazards.

了解盲冲断层（未到达地球表面的断层）的地震潜力对美国洛杉矶和西雅图等人口稠密地区以及周边地震活跃地区的其他人口中心具有重大地震灾害影响世界。关于破坏性地震断层长期行为的关键问题包括地震的规模和频率以及它们在时间和空间上如何变化。 更好地了解过去地震的时间和规模是预测未来事件、描述当地和区域地震灾害以及向公众和应急规划人员提供信息的重要信息。然而，人口稠密的地区很难研究，因为混凝土、建筑物和开发掩盖了活动断层的表现。在这项研究中，正在对阿根廷圣胡安附近的一个活动断层系统进行调查，以更好地了解地表表现和地震，该断层系统与美国大都市区内的盲断层结构相似，但具有该地区基本上未受干扰的优点几个活动盲冲断层的历史。 该项目的重点是对从地震断层变形和断层的河流阶地和冲积层收集的大量样本进行年代测定。根据这些新数据，将确定盲断层系统上过去五次大地震的时间。新时代的数据将能够与早期工作中记录的附近断层系统的地震历史进行比较，这些断层是造成该地区 1944 年和 1977 年破坏性地震的原因。该项目将测试单个断层上的地震频率是否是准周期性的（因此是可预测的），这些断层系统是否产生及时聚集的地震，并测试过去的一些地震是否可能破裂了更大的震源区域或仅限于与历史事件相同的来源维度。与该项目早期阶段的结果一样，阿根廷合作者和其他人将利用该项目的新结果来限制地震灾害，为地震工程师提供信息，并对公众进行有关地震灾害的教育。