SHEAR-WAVE SPLITTING IN THE RECORDS OF THE GERMAN REGIONAL SEISMIC NETWORK

Estimates of the parameters of shear-wave splitting in the records of SKS and SKKS of the new German Regional Seismograph Network (GRSN) for one-layer model show large azimuthal variations at some stations of t he network. It is found that the variations are compatible with the pr esence of two anisotropic mantle layers in the region of the South Ger man Triangle (SGT); the fast direction in the upper layer is between N -S and NE-SW, close to the previously reported estimates of the fast d irection in the subcrustal lithosphere of the SGT. The fast direction in the lower, presumably asthenospheric layer is close to E-W. The est imates of the effective fast direction for one-layer model at the stat ions of the GRSN confirm the previously noted tendency of the fast dir ection of mantle anisotropy in Central Europe to change from 50-degree s - 70-degrees in the western part of the region to 100-degrees - 120- degrees in the eastern part. A correlation of this change with a bendi ng of the present-day direction of maximum horizontal stress in the cr ust suggests that anisotropy in the asthenosphere of Central Europe ca n be related to the Alpine orogeny.