Crustal structure of Mt. Baek-du (Changbai) volcanic region inferred from ambient seismic noise and receiver functions

Mt. Baek-du (Changbai) is a volcano located on the border of North Korea and China. This volcano has been quiet for a fairly long time. However, many geological evidences and historical records indicate that it was active and has a possibility to become active again. In this study, we estimate the crustal structure beneath Mt. Baek-du and surrounding regions using broadband data obtained from the 1998-1999 PASSCAL experiment. Three-dimensional models of vertically (VSV) and horizontally (VSH) polarized shear wave velocities are estimated by ambient noise tomography for Rayleigh and Love waves, respectively. The VSV model shows a prominent low velocity anomaly in the crust beneath the Mt. Baek-du and the anomaly can be interpreted as a magma structure. To study the detailed structure of the anomaly and complement a poor depth resolution of noise tomography, the receiver functions will be used for further analysis. In the same region with low velocity anomaly, strong radial anisotropy (>10%) is observed. Although the cause of strong radial anisotropy is not fully understood yet, it may be related to the complex magma process somehow in this region.