Post-critical SsPmp and its applications to Virtual Deep Seismic Sounding (VDSS) – 2: 1-D imaging of the crust/mantle and joint constraints with receiver functions

Virtual Deep Seismic Sounding (VDSS) has recently emerged as a novel method to image the crust-mantle-boundary (CMB) and potentially other lithospheric boundaries. In Liu et al., 2018 (“Part 1”), we showed that the arrival time and waveform of post-critical SsPmp, the post-critical reflection phase at the CMB used in VDSS, is sensitive to multiple attributes of the crust and upper mantle. Here, we present a synthesis on the methodology of deriving Moho depth, crustal average Vp and uppermost mantle Vp from single-station observations of postcritical SsPmp under an 1D assumption. We first verify our methods on synthetic examples and then substantiate it with a case study using data collected by the Yellowknife and POLARIS array in SW Slave Province, which shows good agreement between crustal and upper-mantle properties derived with VDSS and the ones given by previous studies using active source experiments and conventional P receiver functions (PRF). Moreover, we show that PRF-VDSS joint analysis is capable of placing tighter constraint on average crustal composition, which cannot be achieved with either method alone. We demonstrate with our PRF-VDSS joint analysis that the SW Slave Province, Canada has an intermediate crust composition, which likely indicates a Neoarchean age