High-resolution teleseismic body-wave tomography beneath SE Romania — I. Implications for three-dimensional versus one-dimensional crustal correction strategies with a new crustal velocity model

The CALIXTO (Carpathian Arc Lithosphere X-Tomography) experiment offers a dense, high-quality data set to study the lithospheric/asthenospheric system underneath SE Romania, an earthquake-prone region in SE Europe. To increase the image resolution of structures in the uppermost mantle, the application of crustal traveltime corrections by a priori information before the teleseismic traveltime inversion has become a well-accepted procedure. For such a correction we present a regional 3-D crustal seismic velocity model that serves as the basis for a high-resolution teleseismic tomography (forthcoming paper by Martin et al.). Our 3-D crustal model is based on recent research in the region. We collect new results from two long-range seismic refraction lines, 3-D refraction tomography and teleseismic Ps conversions. Adding previously published models of the sediment distribution, Conrad and Moho depths, as well as crustal seismic P-wave velocities, we compile a 3-D crustal model for SE Romania. This 3-D model does not contain shallow small-scale heterogeneities (