天津近海海底地质灾害类型及声学特征

Acoustic characteristics and types of submarine geological hazards in Tianjin offshore areas

作者利用浅地层剖面资料研究了天津近海海域存在的主要海底地质灾害。研究发现:浅层气、埋藏三角洲前缘、水下潮流沙脊、陡坎、沙波等地质灾害发育。浅层气主要分布在研究区北部海域的近岸附近,南部海域远离海岸浅层气逐渐增多;埋藏三角洲前缘分布区北至涧河口,南至南港工业区东部海域;水下沙脊分布于北部海域5 m~7 m水深的近岸带,地层内部前积斜层理发育;沙波区延伸长度约3 km,整体上在天津海域分布较少;海底表层陡坎出现在天津港及以南海域,其成因主要是航道两侧边缘陡坎或因吹填而抽走的泥沙造成的,近岸及远海地区均有分布。

On the basis of the shallow seismic profile data,the submarine geological hazards in Tianjin offshore areas,which include shallow gas,scarp,buried delta front,submarine sand ridges,and sand waves,were discussed.Shallow gas is widely distributed in the inshore waters of the northern area and the farshore waters of the southern area.The buried delta front is distributed north of the Jian River and south to the eastern sea area of the Nangang industrial zone.Submarine sand ridges are distributed in the nearshore waters of the northern area whose depth ranges from 5 m to 7 m.Inclined foreset bedding exists as an internal formation.Sand waves extend approximately 3 km and are rarely distributed.The scarp is distributed in the eastern and southern sea areas of the Tianjin port,which exists because of channel excavation and land formation and is distributed from nearshore to farshore.