埕岛海区水下岸坡沉积物不稳定运动的区域差异性

    STUDY ON REGIONAL DISTRIBUTION PATTERN OF SUBAQUEOUS SHORE SLOPE SEDIMENT MOVEMENT IN CHENGDAO SEA AREA

    • 摘要: 埕岛海区水下岸坡是海底不稳定活动的频发地带,存在着海底差异冲蚀、残留岗丘、沉积物块体运动等灾害地质,对海上工程设施造成极大威胁。通过对海区多波束、声呐、浅剖等声学调查资料的分析,结合前人研究成果,对水下岸坡沉积物块体运动的区域差异性进行了研究。认为埕岛水下岸坡区沉积物块体运动极为发育,受海区波浪诱发因素的控制,岸坡上部水深3~6 m的区域中,海底沉积物块体运动沿坡向深水方向水平运动的趋势明显,对海洋工程设施影响较大;岸坡下部,沉积物块体运动主要表现为向深部地层的扰动和区域性的失水塌陷压实作用。

       

      Abstract: The subaqueous shore slope in the Chengdao sea is an instable zone in terms of sediment movement, where occur various geological hazards, such as seabed differential erosion, residual mounds, and mass sediment movement, threatening the safety of submarine engineering facilities. Based on the data of acoustic, multibeam, sonar, sub-bottom profiling surveys and previous research works, we made a study on the regional distribution pattern of subaqueous shore slope sediment movement in this paper. It is found that mass movement of sediments is frequent in the subaqueous shore slope of the study area. In the upper part of the slope in the water depth from 3m to 6m, due to the impact of sea waves, mass movement of bottom sediments in the direction of the slope is often observed. It has great threats on the submarine engineering facilities. In the lower part of the slope, however, the mass movement of the bottom sediments is mainly observed as disturbance of the deeper sediments and sediment collapse as well as compaction induced by water escape.

       

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