The Study on the fluctuation of Moho in Yellow Sea and its adjacent area
WANG Hong-xia 1, 2, GUO Yu-gui 3 (1.Qingdao Institute of Marine Geology, Qingdao 266071, China; 2.Ocean University of China, Qingdao 266003, China; 3.Qingdao Municipal Seismological Bureau, Qingdao 266071, China)
With a view to the dynamic mechanism about the formation of earth crust, the authors collect the data of regional geology, geological structure and geophysics. Based on the digitalization, unifying transformation and processing of coordinate, gravity formula, projection and scale of gravity data, the girding is further processed. To separate the regional anomaly from local anomaly for the study of infrastructure, the Trend Analysis Method is used to carry out the calculation of Three-Dimension Multinomial Iteration Matching to the Bouguer gravity anomaly data (Δg) after the preprocessing. The analysis results about the regional Bouguer gravity anomaly such as the second, five and ten trend analyses is obtained. Afterwards using Secondary Grade Proximate Formula Iteration, the three-dimension calculation processing to the five trend analysis results of Bouguer gravity anomaly is carried on. The isoline map of Moho in Yellow Sea and its adjacent area is gotten. The fluctuation feature of Moho is analyzed in the paper. Based on the analysis to the bathymetric map of Moho, the four first grade mantle upheaval-depression units as well as twelve secondary mantle upheaval-depression (salient, sag, slope, convex flat, convex saddle, concave flat) are defined in the paper. The fluctuation of Moho has a better mirror appearance alike corresponding relationship with the nowaday geomorphic shape. The relationship between the deep fractures and fluctuation of Moho is probed into. This provides the evidence for the study on the geodynamics of evolution of infrastructure and active fractures.