LATERAL INHOMOGENEITIES OF THE UPPER MANTLE BENEATH SOUTHERN SIBERIA AND EASTERN KAZAKHSTAN, FROM PP-, SS-, P- AND S-WAVE DATA

Abstract

The proposed study is based upon the joint use of pairs of seismic rays refracted and reflected from the Earth's surface (scheme RR-R). This approach makes possible studies of the upper mantle in "mute" seismic regions where there are no seismic stations and no data are available on local earthquakes. The techniques of estimation of traveltimes by the RR-R scheme allows picking anomaly-produced delays and excluding all other effects on the ray periphery outside the region under study. The obtained upper-mantle image can be efficiently used in studies of lithospheric structure. Thus, the RR-R scheme was applied to investigation of the seismic structure of the upper mantle beneath southern Siberia and eastern Kazakhstan, and, as a result, considerable lateral inhomogeneities of the lithosphere have been revealed.