The effect of temperature anomalies on the thickness of upper mantle transition zone in northwest of Zagros using teleseismic waves

We have computed P receiver functions to investigate the upper mantle discontinuity beneath northewest of Zagros in Iran. We have selected data from teleseismic events (Mb ≥ 5.5, 30 ˚> > 95˚) that have been recorded since 2004 to 2016 at three-component short period and broadband stations from Kermanshah and Khoramabad telemetry seismic network and threecomponent broadband stations in Sanandaj area. The P to S converted phases from 410 and 660 km discontinuities are observed. The results show that the thickness of the upper mantle transition zone in the study area is not the same as that in the entire region, and it is shown a little deviation rather than IASP91 model and appears to be depressed under the Urumieh-Dokhtar zone having northwest-southeast direction. The maximum temperature anomaly is equal to 180˚C and 450˚C for 410 and 660 km discontinuities, respectively.