Because the construction of trans-sea channel of Bohai strait is a strategic marine engineering project, a systematic geological and geophysical investigation as well as analysis in the area is foundamental in the early stage of engineering. In this paper, on the basis of existing information and actual survey, seabed topographical features of the Bohai strait are analyzed, the strata lithologic structure since the Neogene is preliminarily investigated, major active faults are identified, a seismicity analysis on Bohai strait and its neighboring area is carried out, and areas of potential seismic source are divided. The results show that erosion scarp, erosion groove and depression, tidal sand ridge, and underwater shoal are the unfavorable factors of the channel construction. The area along the Changdao islands chain is conducive to the undersea tunnel construction for the bedrock buried depth is shallow. The proposed cross-sea channel is located in the potential seismic source area with a maximum magnitude of 6.0~7.0; the main part of the potential seismic source area with 7.0-magnitude is located within Zhangjiakou-Penglai fault zone, where the key seismic fortification for the engineering is.

Bohai strait  /  trans-sea channel  /  geological conditions