Collaborative Research: Constraints on sediment physical properties at the Cape Fear and Currituck landslides from velocity analysis of new, open access seismic reflection data

合作研究：通过新的开放获取地震反射数据的速度分析对 Cape Fear 和 Currituck 滑坡沉积物物理性质的限制

• 批准号: 1830726
• 负责人: Derek Sawyer
• 金额: $ 13.05万
• 依托单位: Ohio State University
• 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: 2018-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1830726&HistoricalAwards=false
• 关键词: Collaborative; Research; Constraints; sediment; physical

Seafloor landslides that occur just offshore of continents can have significant impacts on coastal areas. On the continental margin offshore of the heavily populated U.S. Mid-Atlantic, about 15% of the continental slope shows scars from large submarine landslides. This study aims to understand the driving mechanisms behind these common features. The role that fluids within the sediments play in triggering landslides will be examined by applying new analysis techniques to existing data. Slope failure can occur gradually or catastrophically, and the type of failure will control the severity of the impacts to coastal areas. Results of this study will provide a better understanding of the following: (1) the natural hazard risk from tsunamis generated by catastrophic slope failures, (2) potential impacts when trapped greenhouse gases are released from both gradual and catastrophic failures, and (3) sedimentary systems along continental margins in a broader scientific sense. The project supports the training of two graduate students and a post-doctoral investigator.The Cape Fear and Currituck submarine landslides offshore North Carolina will be examined using open-access seismic reflection data. A key question for these and other slope failures is "What is the role of elevated pore-fluid pressure in promoting slope instability?" Using pre-stack waveform inversion (PWI) and high-quality seismic data, detailed information on variations in P- and S- wave velocity of sediments inside and outside of these two slide complexes will be obtained. The new velocity information will be integrated with other available information on sediment properties from coring and drilling to constrain variations in sediment physical properties between failed and un-failed regions. Variations in pore-fluid pressure will be estimated using an effective-medium approach relating velocity and effective stress. Also, the seismic profiles will be reprocessed through pre-stack depth migration using velocities obtained by PWI to improve imaging of slide features. This study will add critical new constraints on in situ sediment properties and the stress state within and around the Cape Fear and Currituck slide complexes to the growing body of information on these slides.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.

仅在大陆附近发生的海底滑坡可能会对沿海地区产生重大影响。在人口稠密的美国中大西洋的大陆边距海上，大约15％的大陆坡度显示出来自大型海底滑坡的疤痕。这项研究旨在了解这些共同特征背后的驾驶机制。沉积物中的流体在触发滑坡中发挥的作用将通过将新分析技术应用于现有数据来检查。 斜坡故障可能会逐渐或灾难性发生，并且失败的类型将控制对沿海地区影响的严重程度。这项研究的结果将更好地理解以下几点：（1）灾难性斜坡故障产生的海啸的自然危害风险，（2）当被困的温室气体从渐进和灾难性失败中释放出来时，潜在的影响，以及（3）在更广泛的科学意义上沿大陆沿大陆的沉积系统。该项目支持对两名研究生的培训和一名博士后调查员。将使用开放式地震反射数据来检查北卡罗来纳州的Cape Cape Fear和Currituck潜艇滑坡北卡罗来纳州。这些和其他坡度故障的关键问题是“升高孔隙液压在促进斜坡不稳定性中的作用是什么？”使用堆栈波形反转（PWI）和高质量的地震数据，将获得有关这两个幻灯片复合物内外沉积物的P-和S波速度变化的详细信息。新的速度信息将与其他有关沉积物特性的可用信息集成，从训练和钻孔到限制失败区域和未拖运区域之间沉积物物理特性的变化。孔隙液压的变化将使用有效的中等方法估算，该方法与速度和有效应力有关。同样，使用PWI获得的速度来改善幻灯片特征的成像，将通过堆栈深度迁移来重新处理地震曲线。这项研究将增加对原位沉积物特性以及Cape Cape Fear和Currituck Slide Complexse内部及其周围的应力状态的关键新约束，以在这些幻灯片上的信息越来越多。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛的影响审查标准来通过评估来通过评估来支持的。