Use of Velocity Spectra for Stacking Receiver Functions With Application to IRIS/IDA Stations OBNINSK (OBN) and Arti (ARU), Russia.

摘要

To improve signal to noise ratio (SNR), it is typical to stack receiver functions calculated from events at similar distances and back azimuths. We have adapted the velocity spectrum stacking (VSS) technique from reflection seismology to stack data with different ray parameters and improve the SNR. The VSS technique exploits differences in the shapes of the moveout curves of converted phases and reverberations to separate phases and infer velocity structure. By applying conventional receiver function techniques to the IRIS/IDA seismographic station at Obninsk, Russia we infer a 2 km thick slow velocity surface layer and a 47 km depth to Moho with relatively uncomplicated crustal structure. By comparing VSS computed for OBN and Arti (ARU), Russia with PREM synthetics we have identified Ps phases from the 400 and 670 km discontinuities. We find mantle structure characterized by higher S velocities and deeper discontinuities than PREM. We find no evidence of a 2 10 km discontinuity beneath either station. VSS comparisons between OBN and ARU imply that the 670 km discontinuity is about 2 km shallower beneath ARU than OBN.... Seismology, Russia, Mantle structure, Crustal structure.