NSFGEO-NERC: Latest Pleistocene-Holocene incremental slip record of the Kekerengu-Jordan fault system, northern South Island, New Zealand

NSFGEO-NERC：新西兰南岛北部 Kekerengu-Jordan 断层系统最新更新世-全新世增量滑移记录

• 批准号: 1759252
• 负责人: James Dolan
• 金额: $ 35.41万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1759252&HistoricalAwards=false
• 关键词: NSFGEO; NERC; Latest; Pleistocene; Holocene

The standard model for rupture of large earthquakes along strike-slip faults is that the slip that generates the earthquake occurs on a single surface. The November 14, 2016 Kaikoura, New Zealand, magnitude 7.8 earthquake shook up this thinking about fault slip behavior. In what initially seemed to be an event resulting from slip along a single fault, turned out to be more complex with slip jumping from one fault to another within a network of faults called the Marlborough fault system. In this project, a research team from the University of Southern California, United Kingdom, and New Zealand will use a variety of cutting-edge methods to reconstruct the slip and paleo-earthquake history of one of the Marlborough fault system faults, the Kekerengu-Jordan fault system, which experienced about 12 meters of slip in the 2016 event. Data collected in this project would be used in conjunction with data from other faults in system to better understand earthquake recurrence rates and, more importantly, the temporal and spatial linkage between these faults, something that was clearly not well understood before the Kaikoura earthquake. Understanding the threat from major earthquakes to an increasingly urbanized American population is of critical importance for facilitating proactive and efficient measures to reduce future loss of life and property. Yet understanding of what to expect in terms of the occurrence of large earthquakes in time and space remains severely limited by the current lack of information about how entire systems of inter-connected earthquake faults store and release seismic energy in large, potentially damaging earthquakes. Comprehensive data sets, such as those that will result from this project will reveal how the major faults in a fault system interact with one another to generate potentially damaging earthquakes. These kinds of observations will, in turn, allow for better forecasting of what to expect from similar fault networks in the United States, particularly in earthquake-prone California, but more generally for all of the major faults that underlie large parts of the country. The project has potential to benefit society or advance desired societal outcomes through full participation of women in STEM, increased public scientific literacy with STEM through outreach activities, improved well-being of individuals in society by better understanding of fundamental processes underlying earthquakes that would improve the capability to model earthquake hazards, development of a diverse, globally competitive STEM workforce through graduate student training, and increased partnerships through international collaboration.The primary aim is to advance understanding of the collective behavior of regional fault networks, particularly the importance of emergent phenomena such as earthquake clusters and strain transients that may not be expected in the current understanding of earthquake physics and that are not accounted for in current seismic hazard assessment strategies. Mounting evidence suggests that the occurrence of large earthquakes on both single faults and fault systems is not a random process, with increasing observations of temporal and spatial earthquake clustering, changes in incremental fault slip rates, variations in fault loading rates, and potentially coordinated waxing and waning of slip on mechanically complementary faults in regional fault systems. Although a thorough understanding of both the causes and generality of such phenomena is of basic importance for fault mechanics, earthquake physics, and more accurate assessment of seismic hazard, evaluation of the importance of these behaviors has been severely data limited. In particular, there are too few comprehensive paleo-earthquake and incremental fault slip rate data sets to fully assess the collective behavior of major plate-boundary fault systems in time and space. This study focuses on the Pacific-Australia plate boundary in northern South Island New Zealand in order to document a complete latest-Pleistocene-Holocene (15 ka-present) record of incremental plate boundary slip encompassing all major structures in the system. The research team will build on previous work by developing robust records for the Kekerengu-Jordan fault system, an 85-km-long, oblique reverse-dextral fault system, which is the fastest-slipping fault in the onshore part of the plate boundary at 25-30 mm/year. Slip on the Kekerengu-Jordan fault system generated most of the moment release in the 2016 Mw=7.8 Kaikoura earthquake. The new post-IR IRSL225 luminescence dating protocol will be used at key sites on the Kekerengu-Jordan fault system, and at additional sites located with the new post-earthquake high-resolution lidar data collected by the New Zealand government. This new luminescence dating technique provides precise and reproducible dating of carbon-poor sediments typical of those in the study area with precision roughly equal to that of radiocarbon dating. Combining incremental fault offsets and trench observations with post-IR IRSL225 dating, and carbon-14 analysis will yield detailed fault slip rates and earthquake ages along the fault system spanning individual ruptures back though several dozen earthquakes. In conjunction with existing data sets from both the onshore and offshore faults, including the subduction megathrust that underlies the Kekerengu-Jordan fault system, the research will facilitate a comprehensive, system-level analysis of plate-boundary strain release through time and space during latest Pleistocene-Holocene time.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.

沿走滑断层发生大地震破裂的标准模型是产生地震的滑动发生在单个表面上。 2016 年 11 月 14 日新西兰凯库拉发生的 7.8 级地震动摇了人们对断层滑动行为的看法。最初似乎是由沿着单一断层滑动引起的事件，结果变得更加复杂，在称为马尔堡断层系统的断层网络中，滑动从一个断层跳跃到另一个断层。在这个项目中，来自南加州大学、英国和新西兰的一个研究小组将使用多种尖端方法来重建马尔堡断层系断层之一——Kekerengu-的滑动和古地震历史。乔丹断层系统，在2016年的赛事中经历了约12米的滑移。该项目收集的数据将与系统中其他断层的数据结合使用，以更好地了解地震复发率，更重要的是，这些断层之间的时间和空间联系，这在凯库拉地震之前显然没有得到很好的了解。了解大地震对日益城市化的美国人口的威胁对于采取积极有效的措施来减少未来的生命和财产损失至关重要。然而，由于目前缺乏关于整个相互关联的地震断层系统如何在大的、潜在破坏性地震中储存和释放地震能量的信息，对大地震在时间和空间上发生的预期的了解仍然受到严重限制。综合数据集（例如该项目产生的数据集）将揭示断层系统中的主要断层如何相互作用，从而产生潜在的破坏性地震。反过来，此类观测将有助于更好地预测美国类似断层网络的预期结果，特别是在地震多发的加利福尼亚州，但更普遍的是该国大部分地区的所有主要断层。该项目有潜力造福社会或通过妇女充分参与 STEM、通过外展活动提高公众对 STEM 的科学素养、通过更好地了解地震的基本过程来改善社会中个人的福祉来促进期望的社会成果，从而改善地震的发生。地震灾害建模能力、通过研究生培训培养多元化、具有全球竞争力的 STEM 劳动力，以及通过国际合作加强伙伴关系。主要目的是增进对区域断层网络集体行为的理解，特别是诸如此类的突发现象的重要性作为地震群和应变目前对地震物理学的理解可能无法预料到的瞬态现象，并且当前的地震灾害评估策略也没有考虑到这些瞬态现象。越来越多的证据表明，单断层和断层系统上大地震的发生都不是一个随机过程，随着对时空地震集群的观测不断增加，断层滑动速率增量的变化，断层加载速率的变化，以及潜在的协调打蜡和打滑现象。区域断层系统中机械互补断层上的滑移减弱。尽管彻底了解此类现象的原因和普遍性对于断层力学、地震物理学和更准确的地震灾害评估具有基本重要性，但对这些行为重要性的评估一直受到数据的严重限制。特别是，全面的古地震和增量断层滑移率数据集太少，无法全面评估主要板块边界断层系统在时间和空间上的集体行为。本研究重点关注新西兰南岛北部的太平洋-澳大利亚板块边界，以记录最新更新世-全新世（距今 15 ka）增量板块边界滑移的完整记录，涵盖该系统中的所有主要结构。研究小组将在之前的工作基础上，为 Kekerengu-Jordan 断层系统开发可靠的记录，这是一个 85 公里长的倾斜反右旋断层系统，是位于 2017 年板块边界陆上部分滑动最快的断层。 25-30 毫米/年。在 2016 年 Mw=7.8 凯库拉地震中，Kekerengu-Jordan 断层系统上的滑动产生了大部分力矩释放。新的后红外 IRSL225 发光测年协议将用于 Kekerengu-Jordan 断层系统的关键地点，以及新西兰政府收集的新震后高分辨率激光雷达数据所在的其他地点。这种新的发光测年技术可以对研究区域典型的贫碳沉积物进行精确且可重复的测年，其精度大致相当于放射性碳测年的精度。将增量断层偏移和海沟观测与红外 IRSL225 测年和碳 14 分析相结合，将产生沿着断层系统的详细断层滑移率和地震年龄，跨越数十次地震的单个破裂。结合陆上和海上断层的现有数据集，包括克克伦古-约旦断层系统下方的俯冲巨型逆冲断层，该研究将有助于对最近的板块边界应变随时间和空间的释放进行全面的系统级分析。更新世-全新世时间。该奖项反映了 NSF 的法定使命，并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，被认为值得支持。