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Understanding slow-slipping submarine landslides: 3D seismic investigations of the Tuaheni landslide complex

了解缓慢滑动的海底滑坡：Tuahen 滑坡复合体的 3D 地震调查

基本信息

批准号：
254069062
负责人：
Dr. Jörg Bialas
金额：
--
依托单位：
National Institute of Water & Atmospheric Research - Wellington
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2017-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/254069062?language=en
关键词：
Understanding slow slipping submarine landslides

项目摘要

The dynamics of submarine landslides is only poorly understood. While some landslides rapidly disintegrate others may stay as coherent blocks. Recently, it has been proposed that submarine landslides could also be characterized by very slow (creeping) deformation. The Tuaheni landslide complex off the east coast of New Zealand may acts as key site for investigating such slow-slipping landslides. We propose to collect 3D-seismic data covering different parts of the slide complex by means of the so-called P-cable system. The P-cable system is a cost-efficient, low-fold, high resolution 3D-seismic acquisition system, which can be deployed on relatively small vessels. Ship time for this project will be provided by our New Zealand cooperation partners on the research vessel Tangaroa. Main objectives of the proposed project include the development of a model for landslide evolution, the investigation of the methane hydrate system in the working area with special emphasis on its role for landslide dynamics, and the analysis of the deformations style for the Tuaheni landslide complex. Two competing hypotheses have been postulated to explain the deformation style: i) The Hydrate Valve suggest build-up of overpressure at the base of the gas hydrate stability zone beneath a shallow gas hydrate zone, which causes hydro-fracturing and induces small scale episodic mobility. ii) The Hydrate-Sediment Glacier postulates plastic behavior of gas hydrate bearing sediments resulting in continuous downslope creep. Gas hydrates are known to strengthen sediments during short-term deformation but it is unclear whether they may exhibit plastic behavior during slow deformation, similar to ice.While the Hydrate Valve hypothesis is supported by theoretical models, recent laboratory experiments favor the hydrate-sediment glacier hypothesis. The 3D-seismic data will allow to map deformation indicators (compression, extension, shear zones, decollement) that will help distinguishing the kinematics of creep versus episodic slip. The proposed data would be the first 3D-seismic data set of a slow-sipping submarine landslide. In addition, the data will significantly support planned drilling activities in the frame of IODP (Integrated Ocean Drilling Program) and with the robotic seafloor drilling rig MeBo during an upcoming RV Sonne cruise.

人们对海底滑坡的动力学了解甚少。虽然一些山体滑坡会迅速瓦解，但其他山体滑坡可能会保持一致。最近，有人提出，海底滑坡也可能具有非常缓慢（爬行）变形的特征。新西兰东海岸的Tuaheni滑坡群可能是研究这种缓慢滑坡的关键地点。我们建议通过所谓的p -索系统收集覆盖滑动复合体不同部分的三维地震数据。P-cable系统是一种经济高效、低折叠、高分辨率的3d地震采集系统，可以部署在相对较小的船舶上。该项目的装船时间将由我们的新西兰合作伙伴Tangaroa科考船提供。该项目的主要目标包括建立滑坡演化模型，调查工作区域的甲烷水合物系统，特别强调其在滑坡动力学中的作用，以及分析图阿赫尼滑坡复合体的变形类型。有两种相互竞争的假设被用来解释这种变形类型：1)水合物阀表明，在天然气水合物稳定带的底部，在浅层天然气水合物带下面，超压的积累导致了水力压裂，并引起了小规模的幕式移动。ii)水合物-沉积物冰川假定含天然气水合物沉积物的塑性行为导致连续的下坡蠕变。众所周知，天然气水合物会在短期变形期间加强沉积物，但尚不清楚它们是否会在缓慢变形期间表现出类似冰的塑性行为。虽然水合物阀假说得到理论模型的支持，但最近的实验室实验倾向于水合物-沉积物冰川假说。3d地震数据将允许绘制变形指标（压缩、拉伸、剪切带、脱落），这将有助于区分蠕变和偶发滑动的运动学。拟议的数据将是第一个关于海底滑坡的3d地震数据集。此外，这些数据将为IODP（综合海洋钻井计划）框架下的钻井活动以及即将到来的RV Sonne巡航期间的海底机器人钻井平台MeBo提供重要支持。