Complex structure of mantle discontinuities at the tip of the subducting slab beneath northeast China: a preliminary investigation of broadband receiver functions

Abstract

Broadband seismic waveform data recorded at stations in the western Pacific region are analysed to investigate mantle discontinuities. By using teleseismic deep events, we observe unambiguous P-to-S conversion waves associated with the mid-mantle discontinuities in many of the individual seismograms. Beneath the station in northeast China (MDJ) where the subducted Pacific plate appears to stagnate along the '660-km' discontinuity, the discontinuity response function has more complicated features than those of other stations. The preliminary results indicate no depression of the '660-km' discontinuity at the tip of the subducting slab beneath MDJ; instead a multiple-discontinuity structure down to a depth of 780 km is observed.