Collaborative Research: Tracing the Geomorphic Signature of Strike-Slip Faulting in Marlborough Hill Country, South Island, New Zealand

合作研究：追踪新西兰南岛马尔堡丘陵地区走滑断层的地貌特征

• 批准号: 1321859
• 负责人: Alison Duvall
• 金额: $ 30.57万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1321859&HistoricalAwards=false
• 关键词: Collaborative; Research; Tracing; Geomorphic; Signature

When active, strike-slip faults are among the most dangerous geologic features on Earth. At present, characterizing in detail their slip rates, seismic hazard, and evolution over a range of timescales challenges the earth science community. An under-exploited tool in strike-slip fault characterization is quantitative analysis of the geomorphic response to lateral fault motion to extract tectonic information directly from the landscape. At present, studies of this nature typically focus solely on vertical motion in mountain systems. This research will develop a new framework for applying geomorphic analysis to strike-slip fault systems and in doing so, will move the scientific community toward a more comprehensive and quantitative understanding of the geomorphic response to lateral crustal motion, which we currently lack. A suite of parallel right-lateral strike-slip faults known as the Marlborough Fault System (MFS), South Island, New Zealand offers an excellent natural laboratory for this problem. From north to south, fault initiation ages as well as cumulative fault displacement are thought to decrease whereas slip rates increase over four fold, providing snapshots of different stages of fault evolution. Using the MFS as a natural experiment, this project will test the degree to which surface processes and landforms can be used as a quantitative indicator of lateral fault activity. Geomorphology, thermochronology, and numerical modeling will be applied to document regional erosion history, identify differences (or similarities) in landscape morphology between regions of variable slip rate, fault age, and degree of vertical motion, and make quantitative predictions about the surficial response to different strike-slip fault scenarios using landscape evolution models.The primary goal of this work is to test the degree to which landscape response can be used as an indicator of strike-slip fault activity. Studying the landscape response to strike-slip faulting within the Marlborough Fault System has the potential to improve our understanding of horizontal fault zone activity and the geomorphic response to fault motion, at this location and in general; ultimately mitigating the hazards associated with living in and around strike-slip faults. Seismic activity occurs frequently within the greater Marlborough region, including along faults that were previously unknown (as in the case of the destructive Darfield 2010 magnitude 7.1 and Christchurch 2011 magnitude 6.3 earthquakes). Results from this work will benefit seismic hazard assessment at this location, as well as at many other locations around the world where far less is known about active strike-slip faulting. Detailed study of the timing and magnitude of vertical motion along the primary fault strands as well as along the secondary contractional structures within the MFS will also provide new constraints on the tectonic evolution of the New Zealand orogen and foster already strong international collaboration between U.S. and New Zealand geologists.

当活跃时，滑移断层是地球上最危险的地质特征之一。目前，详细描述了它们的滑移速率，地震危险和在一系列时间尺度上的进化，挑战了地球科学界的挑战。在滑雪断层表征中，探索较低的工具是对横向断层运动的地貌响应的定量分析，直接从景观中提取构造信息。目前，对这种性质的研究通常仅关注山系统中的垂直运动。这项研究将开发一个新的框架，用于将地貌分析应用于滑移断层系统，并在此过程中将科学界迈向对对横向地壳运动的地质响应的更全面和定量的理解，这是我们目前所缺乏的。新西兰南岛的一套平行右侧滑滑断层，称为马尔伯勒断层系统（MFS），为此问题提供了出色的天然实验室。从北到南，认为故障启动年龄以及累积断层位移被认为会降低，而滑移速率在四倍上的增加，从而提供了不同阶段的阶段的快照。将MFS作为自然实验，该项目将测试表面过程和地面可以用作横向断层活动的定量指标。地貌学，热量增长学和数值建模将应用于记录区域侵蚀历史，确定差异（或相似性（或相似性）之间的景观形态之间的差异（或相似性），可变滑移速率，故障年龄，垂直运动程度和垂直运动程度，并对对不同的射击场的降落模型进行验证的指标，以验证景观的响应。走滑断层活动。研究马尔伯勒断层系统内对滑移断层的景观响应有可能提高我们对水平断层区活动的理解和对断层运动的地貌响应，在这个位置和一般而言；最终减轻了与居住在滑滑断层中及其周围相关的危害。地震活动经常发生在更大的马尔伯勒地区，包括沿着以前未知的断层（如破坏性Darfield 2010级7.1和基督城2011年6.3级地震）。这项工作的结果将受益于该位置的地震危险评估，以及在世界各地的许多其他地点，对于主动滑移断层而言，知之甚少。详细研究沿主要断层链的垂直运动的时间和幅度以及MFS内的二级收缩结构还将为新西兰造山机基因的构造演化提供新的约束，并养育了美国和新西兰地质学家之间已经强有力的国际协作。