[S21-2] Seismic images of the upper mantle

[S21-2-02] Tearing of Indian mantle lithosphere from high-resolution seismic images: Implications for lithosphere deformation coupling in southern Tibet

Jiangtao Li¹, ^○Xiaodong Song^{1, 2} (1.University of Illinois at Urbana-Champaign, Champaign, U.S.A, 2.Wuhan University, Wuhan, China)

What happens to the Indian mantle lithosphere (IML) during the Indian-Eurasian collision and what role it has played on the plateau growth are fundamental questions that remain unanswered. Here, we show clear images of the IML from high-resolution P and S tomography, which suggest that the subducted IML is torn into at least 4 pieces with different angles and northern limits, shallower and further in the west and east sides while steeper in the middle. Deep earthquakes in the lower crust and mantle are located almost exclusively in the high-velocity (and presumably strong) part of the Indian lithosphere. The tearing of the IML provides a unified mechanism for late Miocene and Quaternary rifting, current crustal deformation, and deep earthquakes in southern and central Tibetan Plateau and suggests that the deformation of the crust and the mantle lithosphere is strongly coupled.