SEISMOLOGICAL EVIDENCE FOR A VERY SHARP SORGENFREI-TORNQUIST ZONE IN SOUTHERN SWEDEN

A passive seismological experiment across the northern boundary of the Tornquist Fan was carried out from December 1994 until April 1995 alo ng a 100 km long profile in Denmark and Sweden. Observed PS converted seismic waves indicate an abrupt increase in Moho depth of 4-5 km with in 5 km horizontal distance at about 50 km to the northeast of the cir cle divide resund. This is a much sharper jump than that inferred from the wide-angle data of EUGENO-S line 1. Preliminary analysis of seism ic shear wave anisotropy indicates asthenospheric mantle flow parallel to the Sorgenfrei-Tornquist Zone. These parallel directions are alrea dy observed between the Elbe Line and the Sorgenfrei-Tornquist Zone wh ile further south in central Europe the flow directions follow the tre nd of the Alpine belt.