We present the results of an analysis of teleseismic mantle and body wave data observed on digital very broad band stations for the Loma Prieta earthquake of 10/18/1989. Both datasets yield consistent mechanisms with first motion and geodetic measurements. An interesting result of the mantle wave analysis is the realization of a special relation of the geographical position of this event, its source mechanism and the upper mantle degree 2 heterogeneity. Bodywave modelling indicates that the mechanism may be a double shock and could correspond to partitioning of the fault into thrust and strike slip motion. The available teleseismic data in the appropriate distance range are unfortunately not sufficient to lead, to firm conclusions on this point, which should be tested by local observations. ¿ American Geophysical Union 1990