Geological and Geophysical Character of the East China and Yellow Seas

The East China and Yellow seas represent one of the broadest shallow seas in the global ocean, with water depths generally less than 80 m and stretching nearly 750 km from the Shandong Peninsula to the Okinawa Trough (Fig. 1). This area is also unique in terms of the vast amount of sediment it receives from the Huanghe (Yellow River; presently discharging in the adjacent Gulf of Bohai) and the Changjigang (Yangtze River, which flows into the East China Sea). Together, this region receives about ten percent of the river-derived sediment reaching the ocean, and as such, the region has unique geological and oceanographic conditions that reflect both the present highstand of sea level as well as previous lowstands. The purpose of this report is to present and discuss the nature of the seafloor as well as the shallow structure of the surficial (Neogene) strata in the YS-ECS. The maps accompanying this report are the products of the analysis and interpretation of many types of seismic reflection data as well as many previously published papers dealing with this area. Specifically, we have utilized 3.5 kHz echo-soundings, various types of shallow-towed boomer profiles, sparker, air-gun and water-gun data as well as multichannel deep seismic data obtained by the former Gulf Oil Company. Moreover, we have integrated seismic refraction data gathered in the 1960\u27s and 1970\u27s (Fig. 2) in an attempt to gain better knowledge about the acoustic and (thereby) geological character of the deeper Neogene strata