Subsurface imaging is key to understanding the origin of intraplate volcanos. The Changbaishan volcano, located about 2000 km away from the western Pacific subduction zone, has several debated origins. To investigate this, we compared regional seismic tomography with the electrical resistivity results and performed high-resolution 1D and quasi-2D velocity-depth profiles. We show that the upper mantle is characterized by two anomalies exhibiting distinct features which cannot be explained by the same mechanism. We document a localized low-velocity anomaly atop the 410-km discontinuity, where the P-wave velocity is reduced more than that of the S-wave (i.e., low Vp/Vs). We propose that this anomaly is caused by the reduction of the effective moduli during the phase transformation of olivine. The other anomaly, located between 300 km and 370 km depth, reveals a significant reduction of the S-wave velocity (i.e., high Vp/Vs), associated with a reduction of the electrical resistivity, altogether consistent with partial melting.