| Since1980s, the research on the Mass Movements in Yellow River subaqueousDelta has developed greatly. Many findings have been published concerning thequalitative understanding, quantitative analysis and geo-hazard assessment, etc..Furthermore, since1990s, human’s activities have affected the modern geologicalsetting of Yellow River subaqueous Delta in many aspects. The topographical featuresof this area has been affected to some extent, and no analysis has been made on howthese changes can affect the mass movements in this area for now. It is therefore avaluable subject to discuss the changes in mass movements in Yellow Riversubaqueous Delta since1980s. This article is based on some newly aquired submarineacoustic data, in an attempt to analyze the type, trigger mechanism of the massmovement in Diaokou lobe of Yellow River Delta, and the influences posed by thesemass movements on marine structures. The conclusions are: the main type of massmovement in study area is debris flow. Liquefied Flows may occur at some parts ofthe moving sediment mass. The mass movements in study area are small in scale,concentrated, obvious of post-failure erosion features, backward expanding, stronglymixed, locally liquefied, plastic, translational in moving direction. In shallow seafloora well-developed distinct disturbed layer could be found which was caused by mixingin transportation. This layer is acoustically transparent in sub-bottom seismic data.The evolution mechanism is: the sediments of Yellow River subaqueous Delta becomeunstable under gravity stress along slope which was caused by differential erosion andlocalized uneven layers, then slow migration may occur, draining, liquefaction,mixing, redeposit ion may occur during this process. The possible geo-hazards causedby Debris Flow in study area are that the pipeline may be damaged by shear stresscaused by debris flow, and debris flows may happen again by interaction betweenman-made submarine structure and local seafloor. |
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