Collaborative Research: Neogene history of mass transport deposits offshore North Carolina

海底滑坡是大洋两侧北大西洋被动边缘的常见海底特征；它们出现在北美东部边缘是规则，而不是例外。它们威胁着这些海岸沿线的大量人口中心，可能会引发海啸，并在边缘演化期间将物质从浅海转移到深海。尽管被动边缘非常普遍，特别是在美国东海岸，但人们对其原因、机械行为和频率了解很少，也没有研究它们在被动边缘发展中的作用。该项目将使用R/V Marcus Langseth收集新的地震数据，以检查过去2300万年来北卡罗来纳州近海经历过大规模海底滑坡的地区的大型海底滑坡行为。沉积物岩芯将从恐惧角滑坡中提取，这是该地区最新的大型海底滑坡，目前仍在海底表现出来。这些核心将提供对预适应和触发机制的见解。这项研究将加深对斜坡破坏随时间的变化以及过去事件可能影响后续事件的方式的理解，并将为三名研究生和三名职业生涯早期的科学家提供培训和国际合作机会。该项目将收集北卡罗来纳州近海恐惧角海底滑坡附近大陆隆起和斜坡的高分辨率多道地震数据和活塞岩心。这些数据将被用来研究边缘地形、流体和热流、孔隙压力和海底物质传输沉积之间的相互作用。恐惧角地区的物质传输沉积、模拟海底反射和地层序列将被地震成像。新的高分辨率地震数据将与现有的地震和钻孔数据相结合，以解释事件的数量、时间、震源面积、体积、面积范围和跳动长度以及物质传输沉积物的边界表面。地震数据将被用来评估和模拟物质输运沉积和周围沉积物的内部特征，包括变形方式、现今孔隙压力和温度分布以及天然气的存在。该项目包括获取3843公里的二维高分辨率多道地震数据，以及水深、海底剖面仪和水柱数据。将在与渗漏或模拟海底反射有关的位置收集七个活塞和七个重力岩芯。将进行岩土和孔隙流体化学分析。处理后的地震数据将被解释为地层年龄控制、面积范围和物质输运堆积量。将通过地震属性分析来研究物质输运矿床的内部变形。沉积物的物理性质将用全波形反演得到，破坏条件的定量模型将被开发出来。该项目的结果将与了解世界范围内具有类似特征的被动边缘上的海底滑坡动力学相关。该奖项反映了NSF的法定使命，并已通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Submarine landslides are a common seafloor feature of the North Atlantic passive margin on both sides of the ocean; their presence on the Eastern North American Margin is the rule rather than the exception. They threaten large population centers along these coasts with possible tsunamis, and move material from the shallow to the deep sea during margin evolution. Despite their high prevalence on passive margins and in particular, on the U.S. east coast, very little about their causes, mechanical behavior, and frequency is understood, and their role in the development of the passive margin as it exists today has not been examined. This project will collect new seismic data with the R/V Marcus Langseth to examine large submarine landslide behavior over the past 23 million years in a region offshore North Carolina that has experienced large, recent submarine landslides. Sediment cores will be retrieved from the Cape Fear Slide, which is the most recent large submarine landslide in the area and still expressed on the seafloor. The cores will provide insights into pre-conditioning and triggering mechanisms. This study will improve understanding of how slope failures operate through time and the manner in which past events might influence subsequent events, and will provide training and international collaboration opportunities for three graduate students and three early-career scientists.This project will collect high-resolution multichannel seismic data and piston cores on the continental rise and slope in the vicinity of the Cape Fear submarine landslide offshore North Carolina. These data will be used to examine the interplay between margin topography, fluid and heat flow, pore pressure, and submarine mass transport deposits. Mass transport deposits, bottom-simulating reflections, and stratigraphic sequences in the Cape Fear region will be seismically imaged. The new high-resolution seismic data will be combined with existing seismic and borehole data to interpret number of events, timing, source areas, volumes, areal extent and runout length, and bounding surfaces of mass transport deposits. The seismic data will be used to assess and model internal characteristics of mass transport deposits and surrounding sediments, including deformation style, present-day pore pressure and temperature distribution, and the presence of gas. This project consists of acquiring 3843 km of 2D high-resolution multichannel seismic data, along with bathymetry, subbottom profiler, and water column data. Seven piston and seven gravity cores will be collected in locations associated with seeps or bottom-simulating reflections. Geotechnical and pore fluid chemical analyses will be performed. The processed seismic data will be interpreted for stratigraphic age control, areal extent, and volume of mass transport deposits. Internal deformation of mass transport deposits will be examined through seismic attribute analysis. Sediment physical properties will be derived using full waveform inversion and quantitative models of conditions for failure will be developed. The results of this project will be relevant to understanding submarine landslides dynamics on passive margins with similar characteristics worldwide.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.