Seismic Evidence for Lithospheric Modification Associated With Intracontinental Volcanism in Northeastern China

david, fred, r.;

Using data predominantly from the NECESS Array, but also incorporating surface wave data from surrounding networks, we present the results of a Bayesian Monte Carlo inversion of receiver functions, Rayleigh wave ellipticity (H/V ratio) and Rayleigh wave group and phase speeds from 8 to 80 s period for the 3-D shear velocity structure of the crust and uppermost mantle beneath Northeast China. We define the final model as the mean and standard deviation of the posterior distribution at each location on a 0.5◦×0.5◦ grid from the surface to 150 km depth. The primary scientific motivation is to investigate the expression of intracontinental volcanism across the region. The model lithosphere displays prominent features (middle and lower crustal velocity, Moho depth, lithospheric thickness) across the study area that coincide with the location of volcanoes, which are predominantly situated in two distinct volcanic regions, which we call the ‘Northeast China Lineated Quaternary Volcanic Zone’, found near the eastern margin of the Songliao Basin and extending to Changbaishan Volcano, and the ‘Northern and Southern Greater Xing’an Range Pleistocene Volcanic Zones’. There is a strong similarity between the lateral distribution of depth-integrated mantle velocity anomaliesinour model with the teleseismic body wave model of Tang et al., although the vertical distribution of anomalies differ