Abstract:Based on analysis and study of high resolution shallow seismic profile data in the depth of 2131km, structure characteristics in offshore shallow strata in Weihai city have been revealled, the types and distribution characteristics of marine disasters and geological factors have been analyzed, and the distribution map of main disaster geological factors has drawn. The shallow strata in the offshore area in Weihai city can be divided into 5 layers. The first layer is Holocene argillaceous wedge, and the thickness of the strata is 8~15m. The second layer is the transgression layer since the last ice age, and the thickness is generally less than 3m. The third layer is the continental sedimentary layer of MIS2 phase, and the strata thickness is 3~8m. The fourth layer is the marine sedimentary layer of MIS3 phase, and the thickness is 3~6m. The fifth layer is not fully disclosed. The geological factors of the offshore marine disaster mainly include five types, including the buried deep valley, shallow fault, shallow gas, submarine sandy ridge, shallow buried undulating bedrock, etc. The buried valley is mainly distributed in the U3 stratigraphic unit in the southern ocean. The shallow faults are mainly distributed in the southern ocean with the depths over than 20m. The shallow gas is mainly distributed in the northern sea area, and the area in the east and south is small. The bottom of the sandy ridge is mainly distributed in the sea area. The shallow buried undulating bedrock is mainly distributed in the adjacent waters of bedrock coast and island.
