Collaborative Research: Investigating Slip Distribution over Multiple Timescales across the Central Walker Lane: Implications for the Evolution of an Active Tectonic Plate Boundary

合作研究：调查中央沃克巷多个时间尺度的滑移分布：对活动板块边界演化的影响

• 批准号: 1419855
• 负责人: Warren Sharp
• 金额: $ 7.46万
• 依托单位: Berkeley Geochronology Center
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1419855&HistoricalAwards=false
• 关键词: Collaborative; Research; Investigating; Slip; Distribution

The Walker Lane is an enigmatic zone of northwest-trending belt of deformation that straddles the California and Nevada border and is nearly 700 kilometers long. It is primarily characterized by northwest-striking faults that show evidence of right-lateral shear. The faults of the Walker Lane have formed in response to deformation related to relative motion of the Pacific and North American tectonic plates as they slide past one another. The goal of this study is to investigate the spatial and temporal distribution of fault slip and motion along a set of active faults across the relatively narrow eastern part of the central Walker Lane in Nevada. This research will yield the first fault slip rates from right-lateral (dextral) faults using modern geologic techniques collected over multiple time scales on these faults. The results will bracket the timing of dextral faulting and will result in more accurate fault slip rates during the Quaternary (i.e., from about 2.6 million years to the present-day). The data obtained in this study will aid in developing improved estimates of seismic hazards in the region. In addition to the scientific objectives of the study, the project will contribute to strengthening and diversify the geoscience academic workforce through mentorship of two early career scientists; it will promote interdisciplinary research projects through collaborations among students, faculty, and researchers from multiple institutions; it will contribute to the training of the next generation of scientists by involvement in research and high impact inquiry-based course activities; will disseminate these activities to the teaching community for adoption in their own courses to increase geoscience literacy; and will enhance scientific literacy of the public by developing an outreach program of lectures and online land- and aerial-based videos. The project represents collaboration and partnerships between educational and research institutions of diverse scale and mission, as well as with state and governmental agencies. The principal investigators will investigate the spatial and temporal distribution of faulting and fault kinematics along a set of active northwest-striking dextral faults across the relatively narrow eastern part of the central Walker Lane, Nevada. The research involves an integrated program of geologic mapping including terrestrial laser scanning structural and kinematic studies, and geochronology using 40Ar/39Ar, terrestrial cosmogenic 10Be and 36Cl, and U-series dating. The research is motivated by: ongoing GPS studies of contemporary dextral strain accumulation in the central Walker Lane; geologic studies of dextral strain release across wider zones of deformation in the northern and southern Walker Lane; and proposed changes in the forces driving deformation over time including edge forces (related to changing directions and rates of relative motion between the Pacific and North American plates) and internal forces (increased gravitational potential energy as a consequence of recent uplift of the Sierra Nevada). The Walker Lane is a zone of dextral shear that accommodates approximately 25% of the Pacific-North American relative plate motion that is superimposed on Basin and Range extension. Our proposed research program across the central Walker Lane will yield dextral fault slip rates collected over multiple time scales (millions to thousands) and brackets on the timing of dextral faulting. Documenting the strain release patterns along faults in this part of the Walker Lane will allow the principal investigators to characterize the spatial and temporal patterns of strain release along faults in this part of the Walker Lane. Combining these data with similar geologic studies ongoing elsewhere in the Walker Lane, and studies ongoing throughout the Walker Lane will allow the principal investigators to document the magnitude of strain partitioning among the western and eastern central Walker Lane, the adjacent Basin and Range, and the northern Walker Lane. Examination of these data will allow assessment of whether patterns of strain in the Walker Lane have changed in synchrony with known changes in potential driving forces the western U.S. This project will support the continued development and application of U-series geochronological techniques for dating late Quaternary landforms and deposits. The combination of terrestrial cosmogenic radionuclide and U-series geochronology used in this study will provide a comprehensive evaluation of its application to dating late Quaternary landforms and deposits in the Great Basin that will inform future slip-rate studies in this region and worldwide.

沃克巷（Walker Lane）是一个神秘的西北趋势腰带，跨越了加利福尼亚和内华达州边界，长将近700公里。它的主要特征是西北危机的断层，显示右侧剪切的证据。沃克巷的断层是响应于与太平洋和北美构造板的相对运动相关的变形而形成的，因为它们彼此滑行。这项研究的目的是沿着内华达州中央沃克巷相对狭窄的一组活动断层进行断层滑移和运动的空间和时间分布。这项研究将使用这些断层上多个时间尺度收集的现代地质技术产生第一个断层率，从右侧（右侧）断层产生断层率。结果将括起来右旋断层的时机，并在第四纪期间（即从260万年到今天）导致更准确的断层滑动率。这项研究中获得的数据将有助于提高该地区地震危害的估计值。除了研究的科学目标外，该项目还将通过两位早期职业科学家的指导来加强和多样化地球科学学术劳动力。它将通过来自多个机构的学生，教职员工和研究人员之间的合作来促进跨学科研究项目；它将通过参与研究和基于高影响询问的课程活动来为下一代科学家的培训做出贡献；将向教学社区传播这些活动在自己的课程中采用，以提高地球科学素养；并将通过制定讲座和在线土地和天线视频来增强公众的科学素养。该项目代表了各种规模和任务的教育机构与研究机构以及州和政府机构之间的合作和合作伙伴关系。首席研究人员将研究沿着内华达州中部沃克巷相对狭窄的东部相对狭窄的一组活跃的西北右旋断裂，断层和断层运动学的空间和时间分布。该研究涉及一项综合的地质映射程序，包括陆生激光扫描结构和运动学研究，以及使用40AR/39AR，陆地宇宙基因10BE和36Cl以及U系列约会的年代学。这项研究是由：中央沃克巷（Central Walker Lane）中当代右旋应变积累的持续GPS研究；北部和南部沃克巷变形区域右侧变形区域的右旋应变释放的地质研究；并提出了驱动变形随时间的变化的变化，包括边缘力（与太平洋和北美板之间的变化方向和相对运动的变化有关）和内力（由于内华达山脉最近的提升而增加了重力势能）。 Walker Lane是一个右旋剪切的区域，可容纳大约25％的太平洋 - 北美相对板运动，该板层叠加在盆地和范围延伸上。我们在中央沃克巷（Central Walker Lane）上提出的研究计划将产生在多个时间尺度（数百万到成千上万）和右旋断层时机上收集的右旋断层滑动率。记录沃克巷这一部分的故障的应变释放模式，将使主要研究人员可以表征沃克巷这一部分沿断层的空间和时间释放的时空模式。将这些数据与Walker Lane其他地方正在进行的类似地质研究结合在一起，并且整个Walker Lane正在进行的研究将使主要研究人员能够记录西方和东部中部Walker Lane，相邻的盆地和范围以及北部Walker Lane之间应变分配的幅度。对这些数据的检查将允许评估Walker Lane中的应变模式是否已随着潜在驱动力的已知变化而变化。美国西部该项目将支持U-Series Geronological Techniques的持续开发和应用，以约会Quaternary Landforms晚期和沉积物。本研究中使用的陆生宇宙放射性核素和U系数的结合将对其在大盆地的晚期Quaternary Landforms和矿床的应用进行全面评估，以告知该地区和全球范围内的未来滑移率研究。