the lithosphere-asthenosphere boundary in the north-west of iran from s receiver function

recently, the s receiver function method has been successfully developed to identify upper mantle interfaces. s receiver functions have the advantage of being free of s-wave multiple reflections and can be more suitable than p receiver function for studying mantle lithosphere. however, because of specific ray geometry of the s-to-p converted waves, the s receiver function method has some technical difficulties and limitations. we selected data from teleseismic events (mb>5.7, epicentral distance between 60?- 85?) recorded since 1996 to present at 8 three component short period stations from the tabriz telemetry network. clear negative signals from the lithosphere-asthenosphere boundary (lab) are observed. the average lab depth is approximately 85 km and varies from 77 to 103 km underneath the nw of iran.