Slow moving submarine landslides and hydrates

GSTDTAP

项目编号	NE/R016992/1
	Slow moving submarine landslides and hydrates
	Davide Alexandre Gamboa
主持机构	NERC British Geological Survey
项目开始年	2019
	2019
项目结束日期	2019-07-31
资助机构	UK-NERC
项目类别	Research Grant
项目经费	64160(GBP)
国家	英国
语种	英语
英文摘要	Submarine landslides are a major offshore geohazards occurring on continental margins worldwide. The flow and accumulation of landslides offshore can be fairly complex as well. Simple slope failures can have uniform flow characters and create homogeneous deposits, whereas large ones are commonly characterised by differential flow velocities and internal stresses than lead to different internal deformation patterns. The slope failure can be triggered by a variety of processes, such as from major tectonic movements and earthquakes, rapid sediment accumulation rates and fluid overpressure within the sedimentary units accumulated offshore. Despite the possible predominance of a major triggering process, it is likely that slope failure is preconditioned by an association of factors over time. The presence of methane hydrates in the subsurface is one of such factors. These features consist of a cage-like lattice of ice inside of which are trapped molecules of methane under specific conditions of stability. If hydrate stability is compromised, these start to dissociate and release gas and water that will migrate upwards, potentially causing overpressure in the shallower subsurface and favour slope instability. IODP Expedition 372 will drill the Tuaheni Landslide Complex, offshore New Zealand, where a relationship between a slow-moving submarine landslide and underlying methane hydrates has been observed. The expedition will focus on testing three main hypothesis: 1) interstitial gas hydrates in sediments cause creep, akin to an ice glacier; 2) overpressure associated with the hydrates causes hydrofracturing, facilitating the overpressure migration and sediment weakening; and 3) overpressure may lead to slow sliding at the base of the gas hydrate stability zone. The results are expected to shed new light into the current knowledge on the relationships between hydrates and slope failure, and will be applicable to many other continental margins where methane hydrates cover wide areas.
来源学科分类	Natural Environment Research
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/87398
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Davide Alexandre Gamboa.Slow moving submarine landslides and hydrates.2019.