黄河三角洲北部海岸水下岸坡蚀退过程及主要特征

EROSION PROCESS AND MAIN FEATURES OF UNDERWATER COAST SLOPE OF THE NORTHERN COAST IN THE YELLOW RIVER DELTA

黄河三角洲海岸以其独特的成因、演化有别于其它海岸，本文通过对黄河三角洲北部海岸水下岸坡不同时期地形变化对比，展示了在侵蚀阶段潮间带蚀退变化的特征、潮下带斜坡准平衡带的形成及演化，并就其成因和发展作了探讨。

Study of topographic features of the northern underwater coast of the Yellow River Delta shows that the coast has been in an erosion process since 1976. A.Intertidal zone There was strong erosion in this area.It was divided into three parts by geomorphic features:steep slope,gentle slope and uplifted zone.In the intertidal zone,the erosion rate was 1 5km/a in horizontal direction and 0 2mm/a in the vertical direction from 1993 to 1995. B.Underwater cost zone (from low tide line to -15m depth) In this area exists the quasi equilibrium zone.At beginning,there was strong erosion at the bothside of the quasi equilibrium zone,then erosion only occurred up the zone and deposition down the zone,and at last the quasi equilibrium zone became wide and disappeared.