Case study of high-resolution seismic surveys to investigate changes in seafloor topography in the East Sea of Korea

Multi-beam echo sounder (MBES), chirp sub-bottom profiler (SBP), high-resolution multi-channel seismic (HRS), and commercial marine seismic (MCS) surveys were performed to investigate changes in seafloor topography caused by faults in Hupo Basin, East Sea of Korea. A bathymetric map generated from MBES data revealed changes in seafloor topography and fault orientation direction. Chirp SBP data showed an offset in the seafloor topography. However, because of the limited penetration depth (based on sediment type), it was not possible to determine whether the sub-bottom and the underlying sedimentary layers exhibited similar changes. HRS data obtained using a 2,000 J-powered sparker and 16-channel streamer with a 6.25-m group interval did not detect any evidence of changes in seafloor topography because of the same limitations that affected the chirp SBP data. In contrast, other HRS data recorded by a mini-generator-injector (GI) gun with volumes of 30/30 cubic inches and an 8-channel streamer with a 6.25-m group interval revealed deeper reflection events, which provided information about causes of the observed changes. MSC data acquired by a 1,035-cubic inch air-gun array and 32-channel streamer with a 6.25-m group interval showed sufficient penetration depth, but the long wavelength led to low vertical resolution. Overall, the HRS data acquired with the mini-GI gun provided optimal seismic data concerning the survey site.