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

断层加载和应变释放速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的未解决的问题之一。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，应变储存和释放在很大的时间范围内相对连续。然而，最近对东加州剪切带的莫哈韦段的大地测量和地质速率数据进行的比较表明，发生了明显的应变瞬变。这些观测结果提出了几个根本性的重要问题，即应变是如何沿着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东加州剪切带北方半部应变积累和释放的时空恒定性。具体来说，这项工作将重点关注死亡谷-鱼湖谷断层带，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，进入内华达州西南部。通过用宇宙成因核素和光释光地质年代学测定偏移冲积地貌的年代，确定断层系统长度沿着各种地质时间尺度（1 000 - 100 000年）的断层滑动速率。变形的地貌特征是根据机载激光条带测绘数字地形数据进行识别、测绘和恢复的，这些数据是在沿断层沿着两公里宽的条带中采集的，使研究小组能够确定断层带的地貌背景，并捕捉任何次级断层链或断层外变形。将死谷-鱼湖谷断层带确定的地质滑动速率与短期大地测量数据（十年）和该地区其他断层的地质滑动速率进行比较，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时应变积累是否作为太平洋-北美板块边界的一个基本特征向北延伸，与圣安德烈亚斯断层的大弯相关的结构复杂区有关。该研究小组将与美国国家公园管理局在死亡谷国家公园密切合作，向公园游客传播该项目的成果。

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.