Crustal structure in eastern Kazakh, U.S.S.R. from teleseismic receiver functions

Abstract

Broadband receiver functions determined from teleseismic P‐waveforms recorded at two seismic stations in eastern Kazakh, U.S.S.R., are inverted for the vertical velocity structure beneath the stations. The detailed broadband receiver functions are obtained by stacking source‐equalized radial components of teleseismic P‐waveforms. A time‐domain inversion of the radial receiver function is used to determine the structure assuming a crustal model parameterized by flat‐lying, homogeneous layers. The general features of the inversion results are: a complex shallow crust, velocities less than 6 km/s in the upper crust, a high velocity (6.9‐7.5 km/s) lower crust, and a Moho that varies between 47 and 57 km depth. These results compare favorably with a composite velocity model from Deep Seismic Sounding data, but show lower velocities in the upper crust, and higher velocities in the lower crust. The results indicate that the crust in this region is relatively uniform, however the nature and depth of the Moho changes significantly across the region. The receiver function inversion structure for the Kazakh sites is similar to a published receiver function structure for a site on the Canadian Shield.