Collaborative Research: Determination of Slip Rates on the Death Valley-Fish Lake Valley Fault System: Toward an Understanding of the Spatial & Temporal Extent of Strain Transi

合作研究：死亡谷-鱼湖谷断层系统滑动率的确定：了解空间

• 批准号: 0537901
• 负责人: James Dolan
• 金额: $ 9.3万
• 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: 2006
• 资助国家: 美国
• 起止时间: 2006-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0537901&HistoricalAwards=false
• 关键词: Collaborative; Research; Determination; Slip; Rates

The degree to which fault loading and strain release rates are constant (or non-constant) in time and space is one of the most fundamental, unresolved issues in modern geodynamics. Comparisons of short-term geodetic data with very long-term (million year) global plate motion data indicate that, along most plate boundaries, strain storage and release are relatively continuous over a large temporal range. Recent comparisons of geodetic and geologic rate data across the Mojave section of the eastern California shear zone however, point to the occurrence of a pronounced strain transient. These observations raise several fundamentally important questions about how strain accumulates and is released along major plate boundary fault systems. A team of scientists from the University of Southern California, University of Cincinnati, and University of California at Berkeley seeks to understand the spatial and temporal constancy of strain accumulation and release in the northern half of the eastern California shear zone. Specifically, the work will focus on the Death Valley-Fish Lake Valley fault zone, the largest fault system in the region, extending over 300 km from the Garlock fault northward into southwest Nevada. Fault slip rates are being determined at a variety of geologic time scales (1,000 - 100,000 years) along the length of the fault system by dating offset alluvial landforms with cosmogenic nuclide and optically stimulated luminescence geochronology. Deformed geomorphic features are identified, mapped, and restored based on airborne laser swath mapping digital topographic data, acquired in a two-kilometer-wide swath along the fault to allow the research team to determine the geomorphic context of the fault zone and to capture any secondary fault strands or off-fault deformation. Comparison of geologic slip rates determined from the Death Valley-Fish Lake Valley fault zone with short-term geodetic data (decadal) and geologic slip rates from other faults in the region will allow the team to evaluate if the transient strain accumulation observed in the Mojave segment of the eastern California shear zone extends northward as a fundamental feature of the Pacific-North America plate boundary or is alternatively, tied to the zone of structural complexity associated with the Big Bend of the San Andreas fault. The research team will work closely with the U.S. National Park Service in Death Valley National Park to disseminate results of this project to park visitors.

断层载荷和应变释放率在时间和空间上的恒定（或非恒定）程度是现代地球动力学中最基本、最未解决的问题之一。短期大地测量数据与非常长期（百万年）的全球板块运动数据的比较表明，沿着大多数板块边界，应变的储存和释放在很大的时间范围内是相对连续的。然而，最近对加州东部剪切带莫哈韦剖面的大地测量和地质速率数据的比较表明，出现了明显的应变瞬变。这些观察结果提出了几个根本性的重要问题，即应变是如何沿着主要板块边界断层系统积累和释放的。来自南加州大学、辛辛那提大学和加州大学伯克利分校的一组科学家试图了解加州东部剪切带北半部应变积累和释放的时空常数。具体来说，这项工作将集中在死亡谷-鱼湖谷断裂带，这是该地区最大的断层系统，从加洛克断层向北延伸300多公里，一直延伸到内华达州西南部。断层滑动率沿着断层系统的长度在不同的地质时间尺度上（1000 - 100000年）通过宇宙核素和光学激发发光地质年代学测定偏移冲积地貌的年代来确定。根据沿断层2公里宽的机载激光测绘数字地形数据，研究小组可以确定断裂带的地貌背景，并捕获任何次级断层链或断层外变形，从而识别、绘制和恢复变形的地貌特征。将死亡谷-鱼湖谷断裂带的地质滑动率与短期大地测量数据（年代际）和该地区其他断层的地质滑动率进行比较，将使研究小组能够评估在加州东部剪切带的莫哈韦段观察到的瞬变应变积累是作为太平洋-北美板块边界的基本特征向北延伸，还是相反。与圣安德烈亚斯断层大弯曲相关的复杂构造带有关。研究小组将与死亡谷国家公园的美国国家公园管理局密切合作，向公园游客传播该项目的结果。