Evaluation of synthetic crustal geoid for the territory of Poland

The wide angle reflection and refraction seismic experiments performed in Poland in last decade gave us the number of 2D and 3D models of crustal velocities. Precise models of the crust and upper mantle from experiments POLONAISE'97, CELEBRATION 2000 and SUDETES2003 as well as previous profiles LT and TTZ were interpolated into a 3D P-wave velocity model for the whole Poland. The model, parametrized in geographical coordinates system was converted to density model using different equations connecting seismic velocities to densities for crustal rocks (5.57.9 km/s). The density model was used to calculate synthetic geoid elevation for the territory of Poland and to estimate influence of separate layers (topography, sediments, crust and mantle) on the gravity. For calculation we developed a code based on mass point calculation scheme in ellipsoidal reference system. The synthetic geoid undulations were compared to an existing gravimetric quasi-geoid solution. The results show that after eliminating influence of topography, sediments and the crystalline rocks down to the Moho boundary we still observe residual that can be only explained by influence of inhomogeneities in the upper mantle connected both with the variation in temperature and rock composition.