New progress on the onshore-offshore seismic survey in East China Continental Margin

Abstract

The East China Continental Margin (ECCM) is an exemplified natural laboratory not only for studying the origin and evolution of trench-arc-basin system, but also for investigating the deformation mechanism within continent and its margins. For a better understanding on the structure and evolution of the ECCM, a NW–SE trending onshore-offshore seismic profile was recently carried out there using controlled source wide-angle and passive broadband seismic experiments in combination. This 1050-km-long seismic profile transects the East China Sea Continental Shelf Basin (CSB), Zhemin Volcanic Belt, Lower Yangtze Block, and southern North China Craton from East China Sea to continental East China. Preliminary results, such as crustal reflected and refracted phases and P-wave receiver functions, show a good quality of the seismic data and tentatively delineate some first-order characteristics of the crustal structure of the ECCM. Expectably, more detailed crustal seismic velocity and geometric structures along the profile can be constructed by a further processing of the seismic data, and enable continuous and detailed comparisons of the crustal structure and inherent nature among different blocks, combined with other existing seismic profiles in the study region. And these further studies will provide reliable constraints on some controversial geologic issues, such as the origin of CSB, the contacting boundaries and collisional processes among Cathaysian Block, Yangtze and North China cratons. Keywords: Onshore-offshore seismic survey, Controlled source wide-angle seismic experiment, Passive broadband seismic experiment, Crustal structure, East China continental margin