CRUSTAL DYNAMICS IN TURKEY FROM WEGENER MEDLAS SATELLITE LASER RANGING DATA

Satellite laser ranging (SLR) data collected at sites around the world between 1984 and 1990 by the WEGENER/MEDLAS Group (Working Group of E uropean Geoscientists for the Establishment of Networks for Earthquake Research/MEDiterranean Laser Ranging) have been processed to give six annual long arc solutions for the global set of stations and six annu al pseudo-short arc (PSA) network solutions for the European and Medit erranean stations. The first two WEGENER/MEDLAS measurement campaigns involving the mobile SLR stations in Turkey (Diyarbakir, Yigilca, Mele ngiclik and Yozgat) took place in 1987 and 1989. In the first step of this study a global reference frame was defined using most of the fixe d SLR stations. The PSA technique was then applied to a network includ ing both mobile and fixed SLR stations in Europe and the eastern Medit erranean, and station velocities were calculated in the global referen ce frame. The fixed European stations which do not have significant mo tions within the global reference frame were chosen to define a fixed European reference frame. Finally, the station velocities were calcula ted in this fixed European reference frame. The PSA technique shows th at horizontal velocities of stations in Turkey range from 1 to 4 cm/yr relative to this frame. The motions of stations in Yigilca, Melengicl ik and Yozgat are in a north to north-westerly direction. However, the station in Diyarbakir appears to have a motion in an easterly directi on.