2-D and 3-D velocity patterns in southeastern Europe, Asia Minor and the eastern Mediterranean from seismological data

Abstract

Summary 2-D group velocity and 3-D P-wave velocity patterns have been obtained from analyses of the group velocity dispersion of Rayleigh waves in south-eastern Europe and Asia Minor and of the P-wave travel-time residuals along ray-paths with a penetration depth of 100–300 km in southeastern Europe, Asia Minor and the eastern Mediterranean. The inversion procedure used is based on Backus–Gilbert formalism for linear inversion of travel-time data extended to 2-D and 3-D inhomogeneous media. Group velocity distributions have been obtained for periods T= 10, 20, 30 s and are in a very good agreement with the well-known characteristics of the crust and upper mantle structure. They can be used for the construction of models of the crust in south-eastern Europe and Asia Minor. The P-wave velocity patterns obtained for the depth interval 50–300 km are discussed in terms of geophysical (regional isostatic anomaly, heat flow) data for the region. It is proposed that the correlation found to exist between the different mapped geophysical parameters can be explained by compositional changes in the low-velocity layer (the increase of the iron content in minerals).