利用中国、韩国和ISC台站的地震走时数据反演了黄海地区的地壳P波速度结构,对比重力异常和断裂体系、Pn波速度及其各向异性,分析了不同地球物理异常的相互关系以及黄海东部和西部的结构差异,为厘定黄海东部断裂暨中朝-扬子块体的拼合边界提供了新的信息.反演结果表明,北黄海和南黄海西部具有沉积盆地的地壳结构特征,P波速度明显偏低且深度较大,说明盆地内部沉积层较厚、沉降幅度较大,以北黄海、南黄海海州湾和苏北-南黄盆地最为突出.南黄海中部、胶东半岛、辽东半岛和朝鲜半岛显示出构造隆起区的地壳速度特征,其中南黄海中部的高速异常具有北东方向的伸展痕迹,与胶东地区的区域构造走向趋于一致,但是与朝鲜半岛的高速异常并不相连,其间存在明显的分界.据此推测南黄海与朝鲜半岛之间可能存在一个近南北方向的深断裂——黄海东部断裂,至于该断裂是否可以作为中朝-扬子块体在海区的拼合边界,尚需获取黄海东部及朝鲜半岛更详细的相关资料提供依据.
P wave velocity structure in the crust of the Yellow Sea region was inverted by using P wave arrival data from the earthquakes recorded by Chinese, Korea and ISC stations. Taken together with gravity anomaly and fault system, Pn velocity and anisotropy, we analyzed the relation of various geophysical anomalies and the tectonic difference in the western and eastern Yellow Sea. This work provided further information for locating the eastern Yellow Sea fault zone and the collision boundary between the Sino Korea and Yangtze blocks. The crust of the northern Yellow Sea and western South Yellow Sea shows a character of sedimentary basin, and their low P-wave velocities suggest thick deposits and large-scale depressions, particularly in the northern Yellow Sea, Haizhou Bay and southern South Yellow Sea basin. In contrast, the high velocity in the crust of the central South Yellow Sea, Jiaodong peninsula, Liaodong peninsula and Korea peninsula show a character of tectonically uplifted areas. The NE-oriented high-velocity anomalies in the central South Yellow Sea are correspondent to tectonic strikes in the Jiaodongpeninsula, but they are not connected with those in Korea peninsula, obviously separated by a gap. We infer that there may be a NS-oriented deep fault zone (the eastern Yellow Sea fault zone) between the southern Yellow Sea and Korea peninsula, but still need more data from the eastern Yellow Sea and Korea peninsula to confirm its relation with the collision boundary between the Sino-Korea and Yangtze block.