An overview of submarine slope stability and runout assessment for deep water pipelines

Submarine landslides are one of the major hazards for offshore pipelines. Progressive differential ground movements caused by earthquakes can initiate runout/debris flows that can impact and damage the pipelines. Hence it is important to assess both the stability of submarine slopes due to earthquakes and also the potential runout distances. This is particularly important for deep water pipelines whose routes often cross areas that are prone to landslide and debris flow. This paper presents an overview of slope stability and runout assessment for the offshore pipelines using both analytical and numerical methods. Analytical slope stability assessment is based on guidelines for seismic design and assessment of natural gas and liquid hydrocarbon pipelines, while SLOPE/W and QUAKE/W are used for the numerical assessments. The paper provides a state-of-the art review of runout assessments in literature and summarizes the best methodology through a case study.