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

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.