Study On Geomorphological And Geohazards In Bohai Strait Based On High Resolution Acoustic Detection

In recent years, with the rapid development of marine economic development,the investigation and research of mankind on marine geology has enteredhigh-precision, large-scale stage,the requirements of the detection accuracy of seabedtopography and geological disasters are getting higher and higher，High resolutionacoustic detection technology has been widely used and development in thisgeological background. The seabed topography and geological disasters in the studyarea has been detailed described and analysed based on the latest high-precisionsingle-beam depth investigation， high-resolution seismic profile data andhigh-resolution side-scan sonar data and the unique area natural geographicalenvironment， hydrodynamic environment， regional geological backgroundinformation and historical data of Bohai Strait and adjacent seas. The seabedtopography of the study area were classified based on the principle of form causes,found that Bohai Strait is rich in the landform types， Including the coastalgeomorphology and Continental shelf geomorphology, mainly with Continental shelfgeomorphology in the study area, it was mainly divided into Continentalshelf erosion plain of accumulation and Continental shelf erosion depression thirdgeomorphic units,it mainly including the erosion grooves, sand waves, tidal sandridges, shoals, reefs and so on, and they are clearly reflected in the sidescan profile.Through analyzing the controlling factors of the Bohai Strait topography found thatthe structure of the fracture and depression force controls the basic landform patternsof the Strait;the marine regression and transgression caused by the rise and decline ofthe global sea level made a major impact on the early topography of the study area;the erosion and accumulation force caused by the strong trends force in the strait is animportant outside forces factor in shaping the modern Strait landforms; meanwhilethe development of the Bohai economic circle affect the seabed geomorphologyevolution and development of the Bohai Strait. And through analyzinghigh-resolution stratigraphic section acoustic data from the seabed down, The stratumof Bohai Strait is divided into T（0seabed）、T1、T2、T3、T4, etc. four acoustic reflectorsand SU1、SU2、SU3、SU4、SU5, etc.5acoustic stratigraphic units, and the thickness distribution of the various stratigraphic units were drew,found that there are differentdegrees of missing about unit SU1to SU4in the seas of Laotieshan which wasreplaced by the residual sediments. At last the potential hazards of geological factorswere classied the causes and influences were analyzed.They were divided into theerosion scarps, erosion grooves, erosion depressions, rocks, tidal sand ridges, activesand waves, shoal, shallow bedrock surface, shallow gases, active faults, and so on.Meanwhile,the geo-hazard map of the study area has been completed.