Marine geophysical surveys have been performed over the southeastern Yellow Sea, an area composing part of the great North China-Korean platform. A veneer of Plio-Pleistocene sediments covers a broad area of shallow basement called the "Huksan platform." Bordering this positive structural trend, which extends west and southwest of the Korean peninsula, an arcuate series of sedimentary basins is revealed by subcrop patterns below a regional unconformity.

Three exploratory wells that are of significance to a better understanding of the stratigraphy west of Korea have been drilled on the north edge of the study area. Sediments there were deposited in continental environments. High-matrix carbonate in the clastic rocks throughout the section may account for the high interval velocities observed. Although no hydrocarbons were ground in rocks penetrated by the wells, additional drilling on the perimeter of the Huksan platform is required before this large area can be fully evaluated.