Investigation of gas migration as a triggering mechanism for submarine landslides on continental slopes (TRISCO)

气体运移作为大陆坡海底滑坡触发机制的研究（TRISCO）

• 批准号: 401025920
• 负责人: Professor Dr.-Ing. Jürgen Grabe
• 金额: --
• 依托单位: Forschungseinheit Marine Geodynamik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/401025920?language=en
• 关键词: Investigation; gas; migration; triggering; mechanism

Submarine landslides are common along continental slopes worldwide. Fast-moving, large volume landslides can potentially trigger destructive tsunamis. The flows that landslides generate damage and disrupt global communication links and other critical marine infrastructure. While the importance of submarine landslides for society and economy is evident, our understanding of the mechanisms leading to submarine slope failure is limited. Geophysical investigations often provide evidence for the existence of free gas below failure planes. Laboratory experiments have shown that both the presence of gas bubbles and gas driven excess pore pressure may reduce the sediment’s shear strength. It has therefore been suggested that free gas may play an important role for submarine slope stability. We therefore propose to test whether the vertical or lateral migration of gas could be responsible for causing submarine landslides on continental slopes by means of geophysical and geotechnical analyses, thereby aiming to ensure a direct and continuous integration of laboratory and numerical experiments with field data. Advanced analysis of 3D seismic data from two case studies (Storegga and Ana slides) will provide a detailed spatial and quantitative relationship of landsliding and free gas occurrence. Laboratory experiments on gassy sediments and numerical modeling of their constitutive behavior will form the basis for stability analyses of gas-charged submarine slopes. The integration of all results will allow identifying the conditions under which gas-charged continental slopes may fail, which will provide important constraints on future offshore developments and hazard assessments.

海底滑坡在世界各地的大陆斜坡上很常见。快速移动的大规模山体滑坡可能会引发破坏性的海啸。山体滑坡造成破坏和扰乱全球通信连接和其他重要海洋基础设施的流动。虽然海底滑坡对社会和经济的重要性是显而易见的，但我们对导致海底滑坡破坏的机制的了解有限。地球物理调查经常提供在断层下存在游离气的证据。室内实验表明，气泡的存在和气体驱动的超孔压都会降低沉积物的抗剪强度。因此，游离气对海底边坡的稳定性可能起着重要的作用。因此，我们建议通过地球物理和岩土分析来测试气体的垂直或横向运移是否可能导致大陆斜坡上的海底滑坡，从而确保实验室和数值实验与现场数据直接和持续地结合在一起。对来自两个案例研究(Storegga和Ana幻灯片)的3D地震数据的高级分析将提供滑坡和游离气赋存状态的详细空间和数量关系。含气沉积物的室内实验及其本构关系的数值模拟将成为充气海底边坡稳定性分析的基础。综合所有结果，将能够确定充气陆坡可能发生破坏的条件，这将为未来的近海开发和危险评估提供重要限制。