[S21-P] Poster

[S21-P-03] Seismic constraints on thinning of continental lithosphere beneath the Korean Peninsula: A possible link to oceanic slab subductions and mantle transition zone heterogeneities

^○Seongryong Kim¹, Benoit Tauzin², Hrvoje Tkalcic³, Junkee Rhie¹ (1.Seoul National University, Seoul, Republic of Korea, 2.Universite de Lyon, Universite Lyon 1 and Ecole Normale Superieure de Lyon, Villeur, 3.The Australian National University, Canberra, Australia)

High-resolution structures of the entire lithosphere and the upper part of asthenosphere are investigated beneath northeast Asia using independent seismic data and methods. First, three-dimensional shear-wave velocity structures are estimated from transdimensional Bayesian inversions using ambient noise data. Second, a stacking analysis of multi-mode receiver function waveforms are performed to detect spatial variations of seismic interfaces, including Moho and lithosphere-asthenosphere boundary (LAB). The imaged structures from two analyses are compared to confirm highly reliable features. We observe a dipping trend of the LAB to the center of the southern Korean Peninsula (KP) from the continental margin. In addition, more heterogeneous undulation of the lithosphere thickness is shown beneath the northern KP and northeastern China, where rifted basins and intraplate volcanoes are located. We interpret the observations as a thinning of the lithosphere by interactions with extended sub-lithospheric low velocity structures from back-arc regions of Pacific and Philippine-Sea plate subductions (Kim et al., 2016). We further explore a possible relationship of the lithospheric structure to newly observed heterogeneous structures in the upper mantle transition zone (Tauzin et al., unpublished manuscript).