Brief Introduction on the Korea-China Collaborative Research on the Wide-angle Seismic Experiment of the Yellow Sea

Small to moderate earthquakes occurred in the Yellow Sea, such as Seogyuckryulbi-do earthquake (ML 5.1, April 1, 2014) and Heuksan-do earthquake (ML 4.9, April 21, 2013). Although the earthquakes occurred in a region of apparent low seismicity, they attracted much attention for the seismic hazards and rose questions about the reevaluation the seismicity of the Yellow Sea. Although several tectonic models have been proposed from the observations in China and Korea, it is still not clear which one can answer the tectonic problem. Furthermore, the seismicity of the Yellow Sea has been rarely investigated since the region is located outside seismic networks. It is suspected that the seismicity of the region is related to basin boundary faults created by rifting and tectonic inverting. In order to evaluate earthquake hazard of the Yellow Sea, it is required to identify spatial distribution of the faults. In this study, a deep seismic profile was carried out using ocean bottom seismometers (OBS's) to investigate the crust and upper mantle structure beneath the Yellow Sea and their relationship with shallower structures. The deep seismic profile was conducted by M/V Discoverer and R/V Eardo from June 21 to July 3, 2016. The air-gun array of 6,640 cu. in. shot along the 405 km profile across the Yellow Sea, which was recorded by 31 OBS's at a 13.5 km spacing. Besides, 10 temporary land stations were also installed onshore along the profile. This Korea-China collaborative wide-angle seismic experiment was first time across the Yellow Sea. Through this study, it is expected that Korea and China would build a credible cooperation on the study of the Yellow Sea region in future, and it's helpful to verify previously proposed tectonic evolution models for northeastern Asia including the Yellow Sea.