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

海底滑坡是世界各地沿着大陆斜坡的常见现象。快速移动的大体积山体滑坡可能引发破坏性海啸。泥石流造成破坏，扰乱全球通信联系和其他重要的海洋基础设施。虽然海底滑坡对社会和经济的重要性是显而易见的，但我们对导致海底边坡破坏的机制的理解是有限的。地球物理调查经常提供证据，证明在破坏面以下存在游离气。室内试验表明，气泡的存在和气体驱动的超孔隙压力都可能降低沉积物的抗剪强度。因此，有人建议，游离气可能发挥重要作用的海底斜坡的稳定性。因此，我们建议测试是否垂直或横向迁移的气体可以负责造成海底滑坡大陆坡的地球物理和岩土工程分析的手段，从而旨在确保一个直接和持续的整合实验室和数值实验与现场数据。对来自两个案例研究（Storegga和Ana滑坡）的三维地震数据进行的高级分析将提供滑坡和游离气体发生的详细空间和定量关系。含气沉积物的室内实验及其本构特性的数值模拟将为含气海底斜坡的稳定性分析奠定基础。综合所有结果将有助于确定含气大陆坡可能发生破坏的条件，这将对今后的近海开发和危险评估产生重要的制约。

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.